Man.. Havent seen you on in a while. Werent you the guy that had a whole list of mods in the very begining that went on for ever?

I would be surprised if you dont have the GReddy turbo kit on order.. :)

Yeah -- that's me -- I check in every day. No kit on order yet -- I have been patiently waiting for RP's AFSC -- though I must admit it is getting tough with SSR/SFR turbo coming soon. I am going to try to check on that one next week when I am down in AZ. As a former Aero Eng. student (CU-Boulder) I have always has an affinity for RP's solution. I also think an SC will be a better fit for my driving needs. I want to have a kit installed by the time it warms up here in the frozen tundra. I have been ready to write a check for a long time -- just nobody has been ready to send anything for it yet :mad:

Oh well -- I have been entertaining myself by collecting a few Panerai watches :o

My 8 seems happy all snuggled under the covers watching it snow outside. If she wasn't all detailed out I would take her out for some fun since I do have winter rims/tires on her.

Come on RP -- get busy :D

That, a shift kit and anything else I invent by then.

I guess I meant to ask whether or not the AF supercharger can be used to extend the rev limit on the engine?

Does the 2nd paragraph of your answer mean that the unit is designed only for the stock rev range, and that airflow will stall or fail in some way for engine speeds above the stock limit?


I don't think I understand your question. There is enough air to keep going but what would that have to do with the fuel extending itself further. Also I don't think that the fuel cut off is gradual. If it was so then you would have a fatal lean condition. The fuel cut off is used as a rev limiter. At least that is how and why it works on other engines.

Realize that the SC is an airpump as is the engine but the limit to the axial flow is tip speed (among certain other things) so overdrive ratio has to be built to put it's redline with that of the engine. If more air is needed then a longer blade must be designed into the blower. This is not done by the end user.

Some people have claimed that for a bigger engine you just add stages. In fact more stages could do one, the other, or both add more air or add more pressure. depends on which end of the compressor you add them. Added to the front, more air and more pressure. Added to the rear, more compression.

What it means is that you "gear" the supercharger to the top speed of the engine. If you run out of airflow you resize the blower. Simply put, you estimate the airflow of the engine at antisapated redline then get a supercharger that will flow so many times that amount to where you want to flow. Now knowing what the engine flows and what you want it to flow you know the pressure ratio required. Just divide the stock flow by the wanted flow and you have not really a pressure ratio but a density ratio.

Sorry to technical. Pretend there are no losses. Go back to what I said only lets say it gives you the Pr. Example: stock it flows 400 CFM and you want it to flow 600CFM then you would have a 1.5 Pr. Or 7.5 psi in boost. I have a hard time stating it this way because of the real world losses but I said pretend for clearity.

Now you look for a compressor that is running in it's higher efficency range at that point. Then you gear the two pumps to meet at the desired point. This holds true for all compressors even turbos.

I feel I havn't answered your question, have I? Let me go someplace else, do you mean can the engine be coaxed higher with an air pump helping. To a small extent only. The engine which is an air pump just runs into it's own wall of inefficency about the same rpm with or without SC.

This rpm limit can be extended by all the standard hop up things that have been around forever. these extend the rpm and then you rework you original calculations to find the right compressor. Sometimes as with turbos you'll not find the exact compressor you want. It's never perfect so you settle for a point a little down on efficency level.

After you absorb all of this you'll want to know that it must be adjusted for "losses".
This gets a little more involved but I have given the math for it in the begining of the thread.

You dont want to rev much higher since the engine becomes unstable at 14 k

RP -- in all seriousness -- how long would you really need the 8 for to complete your testing??

I'll PM you my cell number, we can talk. I'm tied up for the next hour +, after that if it is convenent for you or late morning my time.

With all this discussion of engine speed and turbine gearing and yahda yahda yahda, I get the sinking feeling that this will be another FI kit that will not be produced for the automatic owners (sounds like an entirely different compressor would be needed). Tell me I'm wrong, please.

With all this discussion of engine speed and turbine gearing and yahda yahda yahda, I get the sinking feeling that this will be another FI kit that will not be produced for the automatic owners (sounds like an entirely different compressor would be needed). Tell me I'm wrong, please.

Considering the auto tranny can't handle much more power, I wouldn't count on much... otherwise Mazda wouldn't have put the low power engine in to start with.

Considering the auto tranny can't handle much more power, I wouldn't count on much... otherwise Mazda wouldn't have put the low power engine in to start with.
Is there a chance you are confused? I thought what Mazda didn't have was an AT tranny that could handle the 9K redline...And if anything, I would think that the AT would be a bit more sturdy than the Aisin 6MT.

Your wrong. Because I'm the compressor manufacture I can make it do what I want. First things first though, lets get the manual working. Honestly the only way we will do the auto is if it is not to far off of the 6 spd. If it requires new castings and such chances are we will not do it. But if it just takes some ratio change and an intake adapter then it might pay. It's just like anything else, the buck rules. Sorry I can't change that.

Is there a chance you are confused? I thought what Mazda didn't have was an AT tranny that could handle the 9K redline...And if anything, I would think that the AT would be a bit more sturdy than the Aisin 6MT.

Exactly, which is why the AT has lower power. While I don't feel the Aisin is the strongest tranny I've ever driven, I would put it's strength up against the 4AT any day. If the torque converter can't handle more than 7500rpm, I wouldn't trust it to high boost either.

There is a train of thought that says the auto box might be "stronger" because it sits behind an engine that puts out more torque (i.e. force). The higher revs is another issue.

Cheers,
Hymee.

Richard there has been a lot of talk on this thread about everything from Superchargers to pulse jet engines.
I was wondering if you could give an update on how the axial supercharger project is coming along and what problems you are still encountering with the unit in the car.
Sorry if this sounds pushy but the thread is starting to sound like a haynes manual for jet propulsion.
:)

I can't always tell everything we are doing. If I dare to tell you that our latest design is going on the dyno this week. I'm sure we are close as far as compressor section is concerned and I'll know soon enough. But the actual layout of the unit is still not firm. With this unit I can redesign it so the inlet and outlet change ends. It is a major redesign as every part changes.

So, to answer your guestion we are about to fit it to the car within the next couple of months. How many detors will be required no one can say.

I hope you post the dyno charts. I believe in you Richard Paul.

I'm sure this will all turn out great.

any new updates??

Buuuuuuuuuuuuuuuuuuuuuuuump.

Interesting supercharger...

I'm going to give you guys an update in about a week. It was going to be this week but got tied up finalizing and starting to ship the shifters.

Richard there has been a lot of talk on this thread about everything from Superchargers to pulse jet engines.
I was wondering if you could give an update on how the axial supercharger project is coming along and what problems you are still encountering with the unit in the car.
Sorry if this sounds pushy but the thread is starting to sound like a haynes manual for jet propulsion.
:)

Bloody hell, Richard.......Mr G McPhee is upset that this thread strays off track occasionally. What are the odds this dude is of British descent??? :)

Big knackers, too. Two posts and he's laying down the law....

Well........let's cut him some slack, maybe he needs some head too. :rolleyes: :rolleyes:

Richard, My turbo thread is catching up to this one ;)

Well Jon, you already have the speed record. Guess I'll just be gracious when it happens. Couldn't go to a nicer guy.

Well Jon, you already have the speed record. Guess I'll just be gracious when it happens. Couldn't go to a nicer guy.


Lol.. first time I read that I could have sworn I saw " RICER guy ".. heh.. so much for my good eyesight. Oh boy, I should delete all my posts on this thread just so I catch up faster ;) just kidding. Thanks again Richard for letting me help you out with that shifter :) I love it.

Ahh - I see - Jon had a clever plan to delay the AFS project by getting RAP to do the short-shift instead!!! :rolleyes:

Cheers,
Hymee.

Probably in kahoots with you. Youcatthrowingbastard ;)

And Hymee, lets not joke about it, he has helped all those potential SC customers to run and buy turbos. He may be the enemy. :rolleyes:

Probably in kahoots with you. Youcatthrowingbastard ;)

And Hymee, lets not joke about it, he has helped all those potential SC customers to run and buy turbos. He may be the enemy. :rolleyes:

Eeek!! Maybe I should just go and hide under a rock for a while until this blows over ;)

I'm still interested in the supercharger :(

Same here

I'm still interested in it as well, but I cant say that I haven't been tempted lately by all the turbo talk. Maybe, Richard, if you posted some information about what to expect out of the AFSC it would help convince people to wait for it instead of running out in droves to buy the turbo.

Weren't you going to strap this puppy on a dyno a week or two ago. You sneeky guy you can't hide from us.

Well, I'd really like to predict what is going to happen but I don't speculate on those things. Even using all the math available to me it isn't a positive until you run it.

I can predict that it will out perform the turbo's in drivablity. It will be easier to install and run cooler. It will not need the intercooler. Also it should not require you to drive around the patterns of the blower curves.

When installed correctly you shouldn't even know it is there.
I can't get this done faster just because people are running out and buying turbos.

It will get done and done right. That's my only statement. We will have some more running time soon but whether or not that info can be released remains to be seen. As I don't own the test engine and am doing it with another company it is up to them if the info can be made public. Sorry but I have to respect their wishes.

you said it wont need a intercooler? But can you put one anyway? Also dumb ? but can you put BOV on this one?

Well, I'd really like to predict what is going to happen but I don't speculate on those things. Even using all the math available to me it isn't a positive until you run it.

I can predict that it will out perform the turbo's in drivablity. It will be easier to install and run cooler. It will not need the intercooler. Also it should not require you to drive around the patterns of the blower curves.

When installed correctly you shouldn't even know it is there.
I can't get this done faster just because people are running out and buying turbos.

It will get done and done right. That's my only statement. We will have some more running time soon but whether or not that info can be released remains to be seen. As I don't own the test engine and am doing it with another company it is up to them if the info can be made public. Sorry but I have to respect their wishes.
No big deal Richard, there are quite a few loyals here and we respect your need for the privacy. We will try to be as patient as we can waiting for such an awesome project to develop. Keep up the good work, and thanks again for doing this. :)

Sure you can put an intercooler on if you want but there will be minimal gain. IC's do have drawbacks you know. This reminds me of the turbo craze in the '80's. The turbo was to be the end all of creation. Hence everything in the world has "turbo" written on it to this day.
Yet we have learned better haven't we. How many turbo cars are the OE making vs SC cars.

IC take resistance to go through them. in certain conditions they can actually add heat. They are hard to fit into the car, the cost alot of money and they are one more thing to worry about. You have all that extra tubing to fill and drain. It makes the car harder to work on and they add weight.

If you can keep the intake air within a usable temp go without the IC. The only time you have to have it is when you reach the thermal limit of the engine internals.
IC by themselves do not add more air to the engine. What comes out of the compressor by mass is all that you get no matter what the temp or pressure.


I've written on this elseware as has rotarygod, you might try searching for it. I can't remember the thread.



Edit)

Forgot about the BOV. This is not a requirment nor can you use it if you want to. That is only used to keep the turbo spinning so there will be less lag. There is no lag with the AFSC. Since the axial flow will be a draw through the duct between the blower and manifold will be at manifold pressure. You wouldn't want to use a BOV connected to the intake manifold would you??

You should take preorders with customers paying like 1/2 full price, and take the money and buy your own 8 to work on.

Just Kidding, thanks for all your hard work and I look forward to this whenever it comes about. The part about being more drivable really interests me so I'll probably wait.

The turbo results are looking impressive with a gain of 50hp at 3k rpms. Can you refresh us on what psi and how many stages your kit(s) will be selling for?

I can't tell you what the price is going to be as I have no idea what we will have in the electronics. We also haven't decided if we will make a new intake manifold from aluminum.
Currently I believe we shall be using four stages and 7 psi. maybe 8. Just depends on how much heat and how much fuel we get.

It looks like the stock fuel pump and nozzles will work. That's something on the plus side.

Even though I have been tempted by the Greddy demons locally, I am still holding out for this myself.

Jon, your only 5 posts behind. That's why I'm telling you this on my thread. I'm sure you'll still see it. I'mm also going to pm or e mail you about something.

Only 3 now...


...err 4 :D

Richard, a hypothetical question: But just assuming you wanted to produce 15 psi of boost and you'd use 8 stages. Now could you instead of using an intercooler, pump cold water through the housing? Compared to other superchargers the axial flow supercharger has more surface area and also the stators are not moving and should therefore be coolable as well. In addition the pressurized air would slightly be cooled after each stage and therefore reduce the total compression work for the same amount of massflow.
Is this feasible or have you actually tried it or are you doing this anyway (I didn't read the entire thread)? Or is the surface area still not large enough to justify an integrated watercooling?

Well first of all we get 18 psi from 7 stages. Now of course you can get some cooling from water around the housing but it wouldn't be enough. Think of the surface area of all those fins in an intercooler. How would you get the water? It would have to be very cold to do any good. In an off shore boat this might be of some use. However lets look at the practical considerations, like how would I make the housing? It has to seal on the ends and if made in two halves each other. I can't see an easy way to even fit it with the draw rods in the way. That would keep you from sealing on the volutes.

Intercoolers are easier and cheaper. Even in the offshore use the absolut best place in the world for intercoolin. You have an unlimited supply of cold water. Even a small cooler placed under water can reject a lot of heat. They do this for the oil anyway. A very small hull shaped housing is put on the trim plates, pumping oil through this removes all the heat needed. The engine should be done with a liquid to liquid cooling system but sometimes they just use sea water to cool the engines which is wrong.

Richard,

My neighbour is a ship/boat builder. He build a large wave piercing cat for this guy 2 years ago. It could go from Aus to US without refuelling. It had a pair of refurbished Gardeners. You could hand crank them if needed.

The point I am getting to is to confirm one of the things you said. The coolant of this boat was circulated through "flutes" in the hull - just looked like the normal pattern you see on the bottom of a aluminium dingy - and that was enough for the heat exhanger. Also they didn't have to worry about a sea-chest, and it getting clogged with injested sea-weed etc. But my buddy said he wouldn't do that again...

http://www.hymee.com/images/GA.jpg

Cheers,
Hymee.

Richard,

My neighbour is a ship/boat builder. He build a large wave piercing cat for this guy 2 years ago. It could go from Aus to US without refuelling. It had a pair of refurbished Gardeners. You could hand crank them if needed.

The point I am getting to is to confirm one of the things you said. The coolant of this boat was circulated through "flutes" in the hull - just looked like the normal pattern you see on the bottom of a aluminium dingy - and that was enough for the heat exhanger. Also they didn't have to worry about a sea-chest, and it getting clogged with injested sea-weed etc. But my buddy said he wouldn't do that again...

http://www.hymee.com/images/GA.jpg
http://www.hymee.com/images/Aug20 the bow.jpg
http://www.hymee.com/images/Aug22 My Gardener3.jpg
http://www.hymee.com/images/jan31 profile.jpg

(BTW - you brought up boats :) :D :p )

Cheers,
Hymee.

Holy shit, that thing is magnifacent. I've never seen anything like it. How can it plane on those thin hulls? Or does it? What is the fabric over the frame? Pattern making? It looks all aluminum except the center hull looks steel?
The engines are in the outer hulls and the fuel also, are there passage ways in and out from the main hull?

I know you didn't build it and I'm asking a lot of questions but that thing is so interesting.

And I'm impressed with you knowing what a "seachest" is. You must have spent some time on a large boat or been in the navy.

Edit) Forget it I can see now that it is ali.

Shame on you Hymee, FOR TAKING THIS THREAD (OF ALL THREADS) so spectacularly off topic..... :eek: :D

It's OK Steve, Philodox is only 4 posts behind. I know he's gonna pass me but make hin sweat it for as long as we can.

It's not to far off topic, I build my big blower for offshore boats. Not that big but they are boats.

YOU SUX Hymee!!! I though rp posted pics thanks for teh large let down. although thats a kicken boat.

Back to 4.

Richard, what does an axial blower sound like on full song? The reason I ask is that I was just listening to the audio of Jon's turbo on his video post. The whistle was a little weird. To the untrained ear of a rotary newbie like me it sounded weird anyway, I've not spent anytime around RX-7 turbos. Sounded far different to a piston engine turbo.

Don't suppose you have any audio you can post?

You may have answered this question before, but I missed it in the 1050 odd post history!

Gomez.

Don't have any audio. Right now it's hard to predict what it will sound like since we have gears in the new one. The first and second designs were to noisy. We don't want to hear the gears over the blower now do we. There is another generation in the test unit now and we shall see. Also the test cell isn't the engine compartment and sound has funny ways of combining with other harmonics to sound different in different enviorments.

This month has slipped by unnoticed so I guess it will be next month when we start in car trial fitting. I really thought we would get it this month. but alas.

Don't worry...If you hurry up and get one installed this thread will be HUGE....:p

Richard, I know you've said that an intercooler will be unnecessary, but let's say you bring your car to the track with this unit installed. Will you have to wait a while between runs in order to let everything cool down? It was terrible with my brother's MKIV Gti pre intercooler, just wondering what differences may be expected. Thanks.

OMG, We're tied, I had to bump my own thread. ;)

OMG, We're tied, I had to bump my own thread. ;)

It's okay Richard.. I like ties.. so here's one for you ;)

richard in a month i wont be needing my car for awhile- its yours for the testing if you can figure out a way to get it from portland to you:)

well i suppose i should consult the wife about that but im sure i can talk her into it:)

Hey Richard, you wouldn't happen to have any pictures of other applications you have made the afsc for? Like the porsche or vette? (I think you mentioned them but I could be mistaken)

here

[IMG]http://www.almar.easynet.be/Latham.JPG

oops that is bigger than i thought sorry

Zoom 44, What did I build that blower for? Looks like a Chevy lower pulley and bracket and idler. But it only has 8 stages, was it a 90 degree V6?
I only remember making one of those and I though it was 7 stages.
If it's the one I remember it went to Katec in MI. for a bowtie six going into a Toyota. For a man in Texas.
Chevy was in on those tests also.

sorry i cheated and did a google search for Latham Superchargers. that pic has a caption that reads:

An American in Brussels ... The only Latham -axial flow supercharger- in Europe is the pride and joy of my superchargers collection.

and can be found on this page http://www.almar.easynet.be/home.htm about 2/3 of the way down.

Sure is a thing of beauty. Looks sexier than a turbo imoh.

hopefully. This mod will only cost as much as wawa junior sub 4.99

As I don't own the test engine and am doing it with another company it is up to them if the info can be made public. Sorry but I have to respect their wishes.


i realize you cant say who but how about a hint?
and i meant it earlier- if you need a car figure out a way to get mine from portland to you and its yours for the testing- ill square it with the wife later:)

and Magix - dont go talking about wawa man - youre making me hungry and the closest wawa is 3000+ miles from here;)

i realize you cant say who but how about a hint?
and i meant it earlier- if you need a car figure out a way to get mine from portland to you and its yours for the testing- ill square it with the wife later:)

and Magix - dont go talking about wawa man - youre making me hungry and the closest wawa is 3000+ miles from here;)

Hmm.. Wawa.. there's one about 1/4 mile away from me ;) those fake cappucino's they serve are pretty good

Hmm.. Wawa.. there's one about 1/4 mile away from me ;) those fake cappucino's they serve are pretty good
When I lived in Jersey I used to go to Wawa's and 7-11's all the time. Don't have like any in NY. On occasion with my brothers we'll stop in at a Wawa on our way to Englishtown for some drag runs. Unfortunately I have no car so I'm forced to watch, but when I get my car and hook up my AFSC :p They'll be seeing my tail lights.

aoshi, to answer your q about heat and intercoolers. I believe that without knowing but betting is that your brothers car has a turbo. That is wwhy everything in the car is hot after a run. If you don't make much heat you don't need to spend time getting rid of it.

When a yturbo is running hard evrything is red hot. That heat has to go someplace. It's going into the water and out the radiator into the air. When you come in after a run it needs more time to get out because it is not moving.

The added radiator helps this condition,

when at home we give directions like this "well you go down such and such road to the intersection with the old WaWa make a left and go a little ways until you get to the Super WaWA ....." etc i always know where i am in relation to the nearest wawa. never know when you are going to want a meatball shortie at 3am :D

so richard-
what DID you build that AFSC in the pics above for anyway?

44 Wanna hint? OK, they do rotary stuff.

I'll talk to you privatly about it the other thing.


I don't know, it has to be a 90 degree chevy V 6. I just can't remember it.

well the SC is in europe now:D

That SC shown is much bigger then the one I'm developing now.
They had a 5.950 rotor dia the new one has 4.4. The stages were 1.0 inch wide the new one is .700 inches. The old one weighed 26 lbs the new one 11.5 lbs.
The old one had intake in the front and radial discharge in rear. New one has axial rear inlet and radial front discharge. But this can be designed reverse. The big one had investment cast rotors and stators. the new one is cut from solid bar stock.

The new one has an internal planetary gearset. The old one had all the overdrive in the belt drive. Old one redlined at 33,000 new one 45,000.

You don't have a car for testing? All of these people in SoCal and nobody has stepped up to offer a tester? Or have I just read things wrong? Do you have a tester with the mystery company? I'd do it if there would be some sort of coverage in case something goes wrong etc.

aoshi, to answer your q about heat and intercoolers. I believe that without knowing but betting is that your brothers car has a turbo. That is wwhy everything in the car is hot after a run. If you don't make much heat you don't need to spend time getting rid of it.

When a yturbo is running hard evrything is red hot. That heat has to go someplace. It's going into the water and out the radiator into the air. When you come in after a run it needs more time to get out because it is not moving.

The added radiator helps this condition,
Yes he has a 2003 Volkswagen GTI. Plus he's got a new turbo in there, when he gets the power on the ground, it's a damned quick car. Back on topic. So superchargers create less heat? Or your supercharger creates less heat? Thanks.

You don't have a car for testing? All of these people in SoCal and nobody has stepped up to offer a tester? Or have I just read things wrong? Do you have a tester with the mystery company? I'd do it if there would be some sort of coverage in case something goes wrong etc.

Ditto. Esp, if it could be installed and tuned on the weekends so I could watch / help.

The savvy mechanics/technicians I've met usually charge a premium if you want to help (get in their way).... :p

Superchargers don't have turbine heat. I know it is normal to believe that turbos are driven by "free" power wasted out the exhaust. This is of course untrue. If you took and put an orfice in the exhaustpipe would it take away power? Why do you pay all that money to get bigger exhaust. Why don't you get smaller exhaust pipes if it doesn't hurt power.

So when you restrict the exhaust the heat backs up and has to go someplace.
You have to have the heat to turn the turbine to turn the compressor.
I'm not anti turbo, I just don't believe that an aftermarket kit can reach the level whereby it is acceptable, at least to me. There have to be so many things taken into consideration that it can only be done at the design stage of the car.

I want a turbo car myself, a Bentley Continental should be in my garage.
That's a twin turbo that can run all day because it was engineered by the factory engineers who insist on perfect. That car was tested in Alaska and the Sahara.
No aftermarket turbo system can take everything effected into account.

Superchargers are only a little better, but they don't have the exhaust problem. Then if you take the supercharger with the lowest heat rise you have the best chance of building a succesfull instillation. The heat rise of a roots blower is totally unacceptable for anything over 4 psi. Maybe 5 but no more. the power and heat that effect these units over those numbers fail to make any extra power.

From there we go up into acceptable ranges with the other SC's. Then there is a large leep to the efficency of the axial flow. There is a trade off for everything and for the axial flow it's that it doesn't produce it's peak pressure through out the range. Not all as bad as it sounds though. because it uses less power to drive and makes less heat it will start to overcome a blower making more pressure at a point lower in the rpm range the you would think.

All this is theory, but it is based on real life experience and good old book
learning. Not on rotary's buton many piston engines I have untold hours of dyno and race time. Not to mention street usage.

By chance anyone get Avanti magazine? I had some published material in there this issue I hadn't expected. But my point is that it brought back to me how long ago I was involved in supercharging for race and street. In there it notes that I had a '64 Studebaker Hawk with a Paxton blown two four bal carbs. 304 inch Stude engine that I drove to school every day and went to the dry lakes with it, changed tires and plugs. Ran 150.5. And that was 1965.

Old ain't I. Truth be known that was the factory number 4 car that ran unblown at Bonniville around the 10 mi course for god knows how many hours to set 53 international records. Then I took it on the NHRA trail and ran for the whole year on the national record hardly ever getting beat. I ran it again with a 259 inch shortblock under the same top end with blower and won class at Bonniville at 155 that was 1966. I think that is when it was retired to street use. By the way, I drove it to Bonniville also.

Bloody Hell, you should be in a museum you sillyoldbastard....

It's crankyoldbastard to you. :)

Get your shifter yet? :( Of course not or you would have said so.

Superchargers don't have turbine heat. I know it is normal to believe that turbos are driven by "free" power wasted out the exhaust. This is of course untrue. If you took and put an orfice in the exhaustpipe would it take away power? Why do you pay all that money to get bigger exhaust. Why don't you get smaller exhaust pipes if it doesn't hurt power.

So when you restrict the exhaust the heat backs up and has to go someplace.
You have to have the heat to turn the turbine to turn the compressor.
I'm not anti turbo, I just don't believe that an aftermarket kit can reach the level whereby it is acceptable, at least to me. There have to be so many things taken into consideration that it can only be done at the design stage of the car.

I want a turbo car myself, a Bentley Continental should be in my garage.
That's a twin turbo that can run all day because it was engineered by the factory engineers who insist on perfect. That car was tested in Alaska and the Sahara.
No aftermarket turbo system can take everything effected into account.

Superchargers are only a little better, but they don't have the exhaust problem. Then if you take the supercharger with the lowest heat rise you have the best chance of building a succesfull instillation. The heat rise of a roots blower is totally unacceptable for anything over 4 psi. Maybe 5 but no more. the power and heat that effect these units over those numbers fail to make any extra power.

From there we go up into acceptable ranges with the other SC's. Then there is a large leep to the efficency of the axial flow. There is a trade off for everything and for the axial flow it's that it doesn't produce it's peak pressure through out the range. Not all as bad as it sounds though. because it uses less power to drive and makes less heat it will start to overcome a blower making more pressure at a point lower in the rpm range the you would think.

All this is theory, but it is based on real life experience and good old book
learning. Not on rotary's buton many piston engines I have untold hours of dyno and race time. Not to mention street usage.

By chance anyone get Avanti magazine? I had some published product in there this issue I hadn't expected. But my point is that it brought back to me how long ago I was involved in supercharging for race and street. In there it notes that I had a '64 Studebaker Hawk with a Paxton blown two four bal carbs. 304 inch Stude engine that I drove to school every day and went to the dry lakes with it, changed tires and plugs. Ran 150.5. And that was 1965.

Old ain't I. Truth be known that was the factory number 4 car that ran unblown at Bonniville around the 10 mi course for god knows how many hours to set 53 international records. Then I took it on the NHRA trail and ran for the whole year on the national record hardly ever getting beat. I ran it again with a 259 inch shortblock under the same top end with blower and won class at Bonniville at 155 that was 1966. I think that is when it was retired to street use. By the way, I drove it to Bonniville also.


Guess that answers my question and a whole lot more. Thanks Richard :)

It's crankyoldbastard to you. :)

Get your shifter yet? :( Of course not or you would have said so.

You (along with the rest of the wired world) will see the pics of the install and my drive impressions as soon as the parcel hits my doorstep. I've taken another two weeks off work, so I should be able to fit it in :D . Actually, the good wife has secured 4th row tickets to the Oz Open Agassi/Federer 1/4 final tonight....so this is the beginning of a good week for me. Like most of Australia, I'm in the Agassi camp....we love to see the underdog(!) get up.

I hope to have the shifter in a day or two.

Gomez.

another Two Weeks??

What kind of car does that Aggisi guy drive that your going to see with your wife??

another Two Weeks??
That should make you feel good Richard. He's taking 2 weeks off of work solely to test your product :D

another Two Weeks??

What kind of car does that Aggisi guy drive that your going to see with your wife??

Ummm, he probably gets about in a Citation. A Cessna Citation, not a Chevy one ;) . There you go, now we're back on topic :D :D :D

What I ment was what sort of cars are those guys racing tonight. You are talking about going to the races arent you?

another
What kind of car does that Aggisi guy drive that your going to see with your wife??

Hahahaha!!! Actually I thought it might be a Learjet.

Cheers,
Hymee.

You are a silly old bastard, aren't you! On the off chance you aren't having a lend of me, I'll state what to most is the bleeding obvious.......Agassi and Federer are TENNIS players! Now you did know that didn't you! If you didn't, you need to get out more.... :)

Oh my, my I'm so blind. You probably mean some guys that hit a silly ball around. ;) And get paid for it. :D :D :D

HEY, MY SHIFTER JUST ARRIVED..... :eek: :eek:

You might try hitting a few balls with it before you put it in.

Sure got your mind off the joking around didn't it?

Hehehe,

When I had lunch with Richard, we walked into this bar in Chatsworth, and these people were all crowded around watching football. I tried to be interested and asked Richard if it was a big game, and who was playing. He replied that since it didn't have anything to do with engines, he wasn't interested :D

Cheers,
Hymee.

Hey Hymee, where did Gomez go? He sure got quiet all of a sudden.

Seriously this is kinda like watching your kids on Christmas. I can just picture him opening his package now. Any bets on how long it will take before it's installed? :eek:

Your a funny bloke, Hymee.

It probably is installed already :)

Why did it have to arrive today, bugger it?? I'm off to the tennis in an hour, the wife is demanding a small parcel of my time. Damn shifter will have to be installed tomorrow now. No sleep for Gomez tonite :) Signing off.....

Gomez.

Well he said in post 1091 that the moment it hit his doorstep we would have pictures. :)

Hymee, I would have installed it....but I want to take photos for the thread.

I wonder if it could be changed on the fly?? If his wife drove and got into high gear on the motorway Gomez could be changing the shifter quick enough so the new one is in before she needs to downshift. :D

I think it could be done.

Take a video of THAT why don't ya.

Well I guess Gomez is off to the tennis. Gomez is loosing sleep tonight. So just to relieve the stress Steve don't loose sleep over me I was having a little go at ya. :) I know who the tennis players are, I don't get wound up over it though.

But everyone knows who your guy Aggisi is.
He's in TV commercials :D :D

Cheers, Crankyoldbastard ;)

Don't know if this has been posted before ... but kind of interesting. A prelude to the AFSC and for those who are looking for sound/video clips ... maybe this is not truly representative, but perhaps you get the idea ...

http://www.rolls-royce.com/education/schools/journey/flash.html

oh thats been done before somewhere about page 27 i think...

Yeah I posted that somewhere around page 25

Gomez, you had PLENTY of time after the tennis last night, so did you get it in?
jack.
BTW off-shorers, today is Australia Day, a public holiday, so expect progress posts from Gomez.

You don't have a car for testing? All of these people in SoCal and nobody has stepped up to offer a tester? Or have I just read things wrong? Do you have a tester with the mystery company? I'd do it if there would be some sort of coverage in case something goes wrong etc.

I'm sure some people have offered... :D I wouldn't know whooo exactly.

And just for Gomez, Federer won pretty handily :D

That is why gomez hasn't called he's bumed out.

If I don't hear from thatgomezbastard soon I'm coming through the wires for him. ;)

Hymee, you know where he is?
This is payback for taking so long to get him one. How does he have that much self control?? ;)

If I don't hear from thatgomezbastard soon I'm coming through the wires for him. ;)

Hymee, you know where he is?
This is payback for taking so long to get him one. How does he have that much self control?? ;)
Maybe he's finished installing it and he's out joyriding? Or like you said, he might just be jerking your chain and making everyone wait. :mad: Just kidding Gomez, can't wait for the pictures and a thorough review. :D

He answered on the other thread. He's photoshoping right now :confused:
Been out driving. :)

Well first of all we get 18 psi from 7 stages. Now of course you can get some cooling from water around the housing but it wouldn't be enough. Think of the surface area of all those fins in an intercooler. How would you get the water? It would have to be very cold to do any good. In an off shore boat this might be of some use. However lets look at the practical considerations, like how would I make the housing? It has to seal on the ends and if made in two halves each other. I can't see an easy way to even fit it with the draw rods in the way. That would keep you from sealing on the volutes.
After seeing Hymees air-water intercooler, I thought about it again. Again as you already mentioned the surface area might be too small anyway. But let's just say it wasn't or you could increase the number of fins on the stators and you'd use seven stages.
The axial flow supercharger consists basically of several rings (well sort of according to the pictures). If each ring had a somewhat larger diameter, you could lathe half-round grooves into these rings. Into each ring you could press an aluminum tube, similar to these guys (just on a cylindrical piece instead of a plate): http://www.lytron.com/custom/custom_cp.htm
Then each tube (7 tubes total) would be connected to a manifold attached to the supercharger and the manifold is connected to a water/air heat exchanger. This could be an approach where you wouldn't have to worry about sealing or assembly issues. The waterflow would be disconnected from the supercharger.

Also if you wanted to even further cool the compressed air after the last stage you could add another stator with a lot of fins and extra wide just for the purpose of cooling the air.

This is interesting because Lytron is helping, the company I work for, build a liquid cooled heatsink for our electronics. We've been playing around with a couple of different configurations and have run a bunch of heat rise tests. The design works really well under ideal situations but we have found the stack up of tolerances might be an issue in production. If the tube is not in solid contact with the plate the efficiency drops significantly and this might be difficult to over come with the construction of Richard's supercharger.

On another note, all of the cold plate manufactures we have talked to (AAVID, Lytron, Wakefield) recommended 6063 aluminum for best results.

This is interesting because Lytron is helping, the company I work for, build a liquid cooled heatsink for our electronics. We've been playing around with a couple of different configurations and have run a bunch of heat rise tests. The design works really well under ideal situations but we have found the stack up of tolerances might be an issue in production. If the tube is not in solid contact with the plate the efficiency drops significantly and this might be difficult to over come with the construction of Richard's supercharger.
Good point. But actually the cylindrical shape of the supercharger has an advantage over the flat plate: Each tube can work like a band clamp, so when you pull the ends of the tube together it will tightly fit the ring of the supercharger.
If the manifold was split, you could use the manifold to tighten the tubes around the supercharger. Or in other words if the inlet section and the outlet section of the manifold was seperated, you could then change the distance between those 2 parts and hence put tension on the tubes. The manifold would serve 2 purposes one to distribute cooling water and one to put tension on the tubes.

Globi,

I was envisioning the tubing spiraling around the supercharger and couldn't see a good way of keeping the copper tubing tight against the housing. Your band clamp idea would probably work a lot better. :D

A round tube even tight hasn't got molecular contact. It still relies on conduction for transfer. There is a minimum amount of surface area when a round surface is touching another surface. There isn't going to be enough cooling here unless you hadsome very cold heat transfer medium.

Next, the number of fins and the amount of area of they have is part of the aerodynamic design. This is known as the solidity and is part of the equations for proper function. There is a very critical balance of many componants in an axial flow compressor. In fact it is one of the most complex of all aerodynamic designs. It has added inputs compared to say a wing.
It is known as a 3 dimentional calculation. It cascades and complicates the problems.

Globi, your going to werar me out with this. I'm glad you found a playmate for your thoughts. Speed Racer, you two keep working on it. Then build me a model and we can test it. One stage will do.

A round tube even tight hasn't got molecular contact. It still relies on conduction for transfer. There is a minimum amount of surface area when a round surface is touching another surface. There isn't going to be enough cooling here unless you hadsome very cold heat transfer medium.

Next, the number of fins and the amount of area of they have is part of the aerodynamic design. This is known as the solidity and is part of the equations for proper function. There is a very critical balance of many componants in an axial flow compressor. In fact it is one of the most complex of all aerodynamic designs. It has added inputs compared to say a wing.
It is known as a 3 dimentional calculation. It cascades and complicates the problems.

Globi, your going to werar me out with this. I'm glad you found a playmate for your thoughts. Speed Racer, you two keep working on it. Then build me a model and we can test it. One stage will do.

Richard, I'm sorry, wearing you out wasn't certainly my intention. I just thought it might be food for thought.

But just to clarify: The round tube would fit into a round groove, so you'd have a surface area of half a tube. The heat transfer from solid to solid is of course much better than from solid to air. So I wouldn't be too worried about this part. We actually use similar aluminum coldplates and they seem to be pretty effective and there's a very uniform temperature distribution eventhough there's a large gap inbetween tubes.

But of course I don't know much about aerodynamic design of axial compressors. I don't even know how hot the housing of that compressor gets. Only a significantly hot housing would justify watercooling. Besides as Hymee did you could always attach an air/water intercooler after the supercharger and still build the whole thing relatively small without increasing the length of the intake tubes. Oh well...

Regarding making a model: I have access to ProE. So I guess I could design the housing and manifold part, but have not much of a clue how to design the fins. ;)

I thought it was determined that the intercooler just wasn't necessary? I think Richard said that the drawbacks of an intercooloer would override and good that it did. Unless this is some sort of new fangled intercooler design, it's all over my head anyway. Keep informing, me likey learny :D

I thought it was determined that the intercooler just wasn't necessary? I think Richard said that the drawbacks of an intercooloer would override and good that it did. Unless this is some sort of new fangled intercooler design, it's all over my head anyway. Keep informing, me likey learny
I was asking him, what if he had more stages and needed an intercooler and what if he wanted to built that all integrated instead of having a seperate unit. Currently he doesn't need an intercooler so it was a hypothetical question.

I couldn't teach you how to do the blades. It's that hard.

But here's a though for you. How about if I made the stator thicker and drilled holes in the direction of flow Axially. Line the holes up when assembling it and somehow feed them from a groove at each end. No extra parts this way. No manifolds to tighten. Best of all you'd have molecular contact.

I actually built a blower that way but used the holes for the draw rods. There were even holes in the rotors for the same reason. But this was not cost effective even for prototyping, as this was.

Like the last words Sundance said to Butch "You just keep thinking." ;)

I was asking him, what if he had more stages and needed an intercooler and what if he wanted to built that all integrated instead of having a seperate unit. Currently he doesn't need an intercooler so it was a hypothetical question.
Ohhh, sorry man. I guess I got confused. It really sounds like a cool idea(at least what I've gathered of it) Thanks for the quick response, I'll read more carefully next time :p

But here's a though for you. How about if I made the stator thicker and drilled holes in the direction of flow Axially. Line the holes up when assembling it and somehow feed them from a groove at each end. No extra parts this way. No manifolds to tighten. Best of all you'd have molecular contact.

I actually built a blower that way but used the holes for the draw rods. There were even holes in the rotors for the same reason. But this was not cost effective even for prototyping, as this was.

I see, well but you still need to seal these holes from stator to stator, but I guess a simple O-ring can do that job...and it would look nicer too (I mean nicer than the tube-idea). I'm surprised that it wasn't cost effective but I believe it.

At Richards request, I'm posting this pic.. He wanted you to take a look at it Omicron

cant see enough of the plane but something about the line of wing leading edge and the angle of the fuselage from cockpit aft makes me think A-10. anyone know the gunghobastard strapped to where a bomb should be?

Agreed, looks like an A-10 Thunderbolt II aka the Warthog. The plane that is, not the guy (although he does remind me of a warthog in profile...). :)

cant see enough of the plane but something about the line of wing leading edge and the angle of the fuselage from cockpit aft makes me think A-10.

I think you're correct

picture is huge, so here's a link to it...
A-10 (http://www.mabarn.ang.af.mil/A10_8X10.jpg)

The low swept wing and the weapons plyons are the give away. I'm not sure what an M-16 would add to the GAU-8 in the nose (30 mm rounds @ 3900 rounds/min). See http://www.af.mil/factsheets/factsheet.asp?fsID=70 for more tidbits.

Interesting fact: The A-10 uses two turbo fan engines. Rather unique for a combat aircraft. The turbofan is an axial flow supercharger shafted to a low pressure turbine with a combustion chamber in between. Whew, finally back on topic...

Interesting fact: The A-10 uses two turbo fan engines. Rather unique for a combat aircraft. The turbofan is an axial flow supercharger shafted to a low pressure turbine with a combustion chamber in between. Whew, finally back on topic...

Hhaha, as soon as I saw Philodox's plane I laughed and thought to myself "It's on topic at least"......Boats are off topic :D

Yea, that's what I thought(A 10) But the heading said A 160. I know we don't use three digit references except the F 117 (I don't know why that is excepted) Maybe it is a subheading, or a misteak. They use letters for subheadings.

Must be a misteak. It came from my kid, He reads this thread. David, what the hell is a A160.

Interesting fact: The A-10 uses two turbo fan engines. Rather unique for a combat aircraft. The turbofan is an axial flow supercharger shafted to a low pressure turbine with a combustion chamber in between. Whew, finally back on topic...



I think this was one of the first to use such an engine. Or was it just a strange place to use one. can't remember which. Got that from Turbine_pwr. If anyone cares we can ask him.

Gomez, boats run turbines too. :rolleyes:
Thats all they have in modern ships.
Nuc/subs have turbines.

I know, but this is an aeroplane thread Richard. Don't go stuffing it up and upsetting the off topic nazi's by going and bringing boats into it......

You haven't got time for this anyway. Back to work.

So Richard, you may have beaten me to the punch, but I was thinking, that instead of using a tube, why not drill a tube into the inside of the stator, or basically hollow it out in the middle somewhere, and run the water through that. The stator stage itself becomes the tubing.

I'm not sure if something like this could even be machined, but if it were possible this seems to be the best cooling solution, internally.

RP,

The TF-34 engine is used in the A-10. As you pointed out it's a high bypass turbofan. It has a fan that is connected to a low pressure turbine. But it also has an axial flow high pressure spool that is driven by a high pressure turbine. The combustor is between the hp compressor and the hp turbine. Most of the airflow that goes through the fan... bypasses the core engine and just exits out the nozzle. However, in the process, energy is transfered to that air which results in the generation of thrust. The primary purpose for such an engine is that it yields better fuel consumption than a turbojet because of improvements in propulsive efficiency.

The first use of a high bypass turbi fan was in the C-5A... this then translated into the following commercial aircraft. Today almost all new commercial and business aircraft use high bypass turbofans (benefits - better fuel consumption and reduced noise).

Relative to the cooling discussion: Most gas turbine engines now use turbines that are operating at inlet temperatures that are in some cases above the melting temperature of the metals. To keep these metals cool and allow them to survive... they have very sophisticated cooling schemes and use TBC coatings (thermal barrier coatings). The crazy thing is that we typically use compressor exit air as the coolant (it's typically 800-1400F). However, if you're trying to cool a blade that is seeing 2200-3200F gas temperatures 800-1400F seems cool. Thes blades are typically cast. Newer more sophistcated designs are directionally solidifed or single crystal casting and they have multi-pass internal passages with trip strips and turbulators to increase local heat transfer. This is very cool stuff that operates in very hot temps. Bottomline: Cooled internal passages in stationary and rotating bladerows have been done and can be effective. However, the process ain't cheap. The use of water as a coolant would improve cooling effectiveness and reduce the impact of the fact that you have very limited surface area to transfer heat. However, I'm guessing that it would be difficult to get significant temperature benefits.

However, if you were able to remove as much temperature as each stage addes... you would have created a stepwise equivalent to an isothermal compressor which has dramatic reductions in power required to compress air. I will leave it up to the interested reader to look up isohermal compression in their old thermo text and identify the equations to calculate the work required to deliver 7-10 psi of boost for a RX-8 sized AFSC.

Regards

Good to hear from you John. Did you ever get my message about Professor Easwaren. Speaking of coatings. There is a thread with your name in the title somewhere. Anywat I'll go again, but let me opost this so you don't go way

Dr Jay Easwaren was my materials Prof at Western Mich U. He was also my sons. Yes, he was ours, we owned him. Before I get the wise remarks.

Today He owns a company in AZ that overhauls APU's. Since he must have something to do with you company I thought you may know of him. He also has a company in Indy that makes turbine blades.
On his rebuilds he puts some of his coatings on the hot section.

He was a whizz with coatings. I had to machine a lot of things for him over the years. If you met him you'd remember, he is the Walt Disney absent minded professor. All genuis, nuts everywhere else. I once asked him why he wasn't wearing any socks? He said "the stranger I dress the more the kids think I know."

The reason I started to think about him was that someone asked about coatings inside the ren exhaust ports.

Check for that thread and a PM I also sent in this regard.

Richard, here's a few pics of the internal cooling passages Turbine Pwr is talking about.

This blade is out of a CFM 56-3 I think...B737 Classic.

Interesting fact: The A-10 uses two turbo fan engines. Rather unique for a combat aircraft. The turbofan is an axial flow supercharger shafted to a low pressure turbine with a combustion chamber in between. Whew, finally back on topic...
Gotta love the aircraft thread!

The A-10 is interesting because it uses a relatively high-bypass ratio turbofan. It is not unique for being a turbofan though. All modern combat aircraft since the mid-1970's have used turbo fan engines. Most of them are low-bypass ratio turbofans, but they are turbofans none the less. You name them - F14, F15, F16, F18, F117, F111. You have to go back to the 1960's to find turbojets.

What's also intersting about the A-10 engine (TF-34) is that the same engine is used in the US Navy S-3 Viking. (pic below)

Wildcard,

I need a little edumacation...

I guess the high bypass can easily be distingiushed from the low bypass, by the "big" fan on the front.

So, I understood that turbofan engines make a good percentage of thrust from the fan itself, sorta like a big, hitech multiblade prop. Is that correct? And do the lower bypass engines, such as in your daily driver, produce a much higher percentage of their thrust from the exhaust?

Interesting stuff this :)

I saw some pretty good pics of a Warthog that had been shot up pretty bad in the gulf a few years ago. I guess it was Desert Storm. But it made it home OK.

Cheers,
Hymee.

Wildcard,

I need a little edumacation...

I guess the high bypass can easily be distingiushed from the low bypass, by the "big" fan on the front.

So, I understood that turbofan engines make a good percentage of thrust from the fan itself, sorta like a big, hitech multiblade prop. Is that correct? And do the lower bypass engines, such as in your daily driver, produce a much higher percentage of their thrust from the exhaust?

Interesting stuff this :)

I saw some pretty good pics of a Warthog that had been shot up pretty bad in the gulf a few years ago. I guess it was Desert Storm. But it made it home OK.

Cheers,
Hymee.

The A-10 sure can take a beating. The A-10 I saw from Desert Storm had holes all over. It still flew, but missed the runway a tad when he landed. The pilot then excused his bad landing.
If shrapnel enters the engine, the engine is designed to "spit" it out and restart.

They built the gun (GAU-8A) and then the plane around it.

So Richard, you may have beaten me to the punch, but I was thinking, that instead of using a tube, why not drill a tube into the inside of the stator, or basically hollow it out in the middle somewhere, and run the water through that. The stator stage itself becomes the tubing.
I'm not sure if something like this could even be machined, but if it were possible this seems to be the best cooling solution, internally.
The problem with machining is that there's always a tool involved that's connected to some machine. So no hollowing it out there unless you have a really really microtiny machine or a trained ant with a micro-chisel.

But you could possibly do some lasersintering if you don't mind paying a fortune:
http://www.warwick.ac.uk/atc/rpt/Techniques/sintering.htm

However, if you were able to remove as much temperature as each stage addes... you would have created a stepwise equivalent to an isothermal compressor which has dramatic reductions in power required to compress air. I will leave it up to the interested reader to look up isohermal compression in their old thermo text and identify the equations to calculate the work required to deliver 7-10 psi of boost for a RX-8 sized AFSC.
I guess that's what I was also getting at with that whole cooling thing. More efficient isothermal vs. adiabatic compression. Wouldn't it be nice to have an electrically powered (regenerative braking) water cooled axial flow supercharger on a miller cycle gasoline engine? :)

But Richard made it clear that watercooling is too costly besides the added complexity. After all most people want more power and not more mileage otherwise they probably would have gotten a Prius in the first place.

Yeah finally got to the end of this thread. :)
Just wondering when I get my BEng in Jet Propulsion :rolleyes: through the post.
After reading all this I have slightly lost track of the power gains expected from this supercharger project.
Surley we should roughly know what ball park the supercharger will be playing in.
25hp, 50 hp, 100 hp, 125hp, 150hp.
Please say if you think I am turning cynical. But I am ready for FI in the 8 and a lot of companies have my interest in there turbo kits. I really dont want to go down the turbo road. Supercharging the beast looks like the best option.
Have any of you turbo junkies actually ran your 8 with a straight through exhaust system? I mean with the cat out!!! It totally stinks of oil.
And I dont want to be passing these oil filled gases through something that runs as hot as the turbo.
I know it is probably totally safe to do this, just not my cup of tea.
And I know RP doesn't want to say what the supercharger is going to do, I'm not asking for exact figures just the ball park this supercharger will be playing in or round about.
I am hoping for around the 100hp.
But bearing in mind I am from across the vast big pond, the last product I bought from you mericans/canadians did not work for my UK spec 8 you could say that I am slightly sceptical.

Yeah finally got to the end of this thread. :)
Just wondering when I get my BEng in Jet Propulsion :rolleyes: through the post.
After reading all this I have slightly lost track of the power gains expected from this supercharger project.
Surley we should roughly know what ball park the supercharger will be playing in.
25hp, 50 hp, 100 hp, 125hp, 150hp.
Please say if you think I am turning cynical. But I am ready for FI in the 8 and a lot of companies have my interest in there turbo kits. I really dont want to go down the turbo road. Supercharging the beast looks like the best option.
Have any of you turbo junkies actually ran your 8 with a straight through exhaust system? I mean with the cat out!!! It totally stinks of oil.
And I dont want to be passing these oil filled gases through something that runs as hot as the turbo.
I know it is probably totally safe to do this, just not my cup of tea.
And I know RP doesn't want to say what the supercharger is going to do, I'm not asking for exact figures just the ball park this supercharger will be playing in or round about.
I am hoping for around the 100hp.
But bearing in mind I am from across the vast big pond, the last product I bought from you mericans/canadians did not work for my UK spec 8 you could say that I am slightly sceptical.
I wouldn't be worried about this kit not working on your car. Unlike many other forced induction kits, this kit is built for the RX8 alone. It's not a generic blower. Richard is taking every measure to make sure this is perfect for our car. I don't know where exactly you are from, but I don't think anything could be too different so that this blower wouldn't fit correctly. It's pretty damned small. Hope that helped.

... If you met him you'd remember, he is the Walt Disney absent minded professor. All genuis, nuts everywhere else...

That is kinda funny you saying that ;)

Hey - I might be able to catch up again in April. I guess it is my turn to get lunch this time!

Cheers,
Hymee.

Don't forget the drinks mate. :D

Is that how you spell "mate", doesn't look right.

Actually, yougotitrightyabastard.

Cheers,
Hymee.

It's Crankyoldbastard, how many times must I tell you.

okyougotitrightagainyacrankyoldbastard

:eek:
There has still been no reply to the question of approximate gains this axial supercharger will give.
Roughly please
50hp, 100hp, 150hp???????
:D

The target is a max of 300 fwhp. How close it gets to this goal has yet to be seen.

:eek:
There has still been no reply to the question of approximate gains this axial supercharger will give.
Roughly please
50hp, 100hp, 150hp???????
:D

Ok, I have said on this thread and others that I don't like to predict HP gaines by boost pressure. I can figure Density ratio which I like bbetter but there are still variables. Judging from what has just transpired with philodox car and the Greedy turbo I have a clue.

Jon is running about what I think is reasonable for the stock fuel system ans compression ratio. However I think I can produce that boost using less power from the engine and it should have more mass. It should be cooler at least not hotter. That is without an IC. I also think it will run better with a drawthrough system.

So what do I think? About 80-85 HP increase. There is more to be had but it costs more and is more work to install. Also if you start getting into higher pressure You'll need better fuel or less compression.

In the end there will be a wall at 300 crank hp. from there it's going to cost. If your the guy who is going to buy FI from whoever tells you he can give you the most power have them show you on someone elses dyno.

There are companys out there right now saying their intake or exhaust will give you 15 or more hp from each one or 30+ hp if buy all there parts. Then you have Racing Beat telling you that their exhaust may give you 3 HP. And they haven't found anyones intake that gave more then 2 with some loosing power. Who should you believe?

If they found any power they would love to sell it to you. When I sold blowers for V-8 engines I told the truth about what the engines made and lost sales o companys that claimed more. But when the magazines tested them my blower more then doubled the increase of the best of the others. Everyone using the same boost.

That's it for tonight

So what do I think? About 80-85 HP increase.

No!! Did Richard just do the unexpected? He just speculated on the horsepower gains of his forced induction kit. Do we all know what this means? Richard is bound to drop off the face of the planet for the next year! Why? Because every other vendor on this forum that has claimed figures has done so. Usuallly within 24hours! I want to be the first to call dibs on Richards workshop! :p

Here's an air density calculator, if one wants to see how much air density and therefore power output can actually change depending on temperature, pressure and humidity of the surrounding air.
http://wahiduddin.net/calc/density_altitude.htm (scroll down to the purple thingy)

So a power claim or a dynosheet is really only useful if these 3 parameters are also stated.

For a Dyno to be standards compliant (i.e SAE), it is supposed to apply a correction to the measured figues using the current atmoshperic conditions. The corrections are designed to standardize the figures to a standard temp, pressure, humidity.

That said, it seems you still make more corrected power on an ideal (cool, dry) day.

Cheers,
Hymee.

I don't know about some of these chassis dyno's but modern engine dyno's take this information into the correction factor. On my Superflow it colected the borometric pressure and temp by itself. The vapor pressur is put into it by the operator after using a sling psycometer. I don't know how it's spelled.

This is a wet bulb dry bulb instriment. Did yoou guys see the operator swing an instriment around in the air and put some input into the dyno? If not then the dyno didn't know all it needed to know for corrected read outs.
There are units that can read this by themselves though so you can't be sure.

The point is that this is an input and you don't have to use it yourself. The dyno does it for you befor it gives you the numbers. Without this being used in the calculation there would be no reason to even compare power readings like you guys are doing. Don't even post them, they're worthless except to see on the same day if the weather doesn't change to see between runs if you have made any more power. you may as well read out in any sort of numbers. Like one dyno could read out in four digits while another in two. I have 2754 units of power in my car. You have 110 on the same car but a different type dyno.

Dynos have to be able to compare with each other, that is why they calabrate them. It's a simple thing to do. Just hang a known weight at a known distance from center and read lbs of torque. Then you know if it is right. You check it with several different weights to check the range.

I think it was Engle that had a dyno built using one of those big scales that they used to have to weigh yourself on in public places by putting in a dime. Except this one was so old it took pennys. "Ready to make a run, someone go put a penny in the scale" True story from the late '50's early '60's. (No I was in high school then.) They probably stole the scale from a bus station. :rolleyes:

Now they just use a strain gauge. Cheap and accurate. The dyno probaly can print out in Std or SAE though. Since Std reads higher everyone uses that.
The car companys use SAE. Which brings us o another point. Mazda is claiming Their rating in SAE and no one else can even get it to read their numbers using Std! Whats up with that??

So, the HP reading depends on many parameters like the accuracy of the strain gauge, the accuracy of the pressure, temperature and humidity reading and when they were last calibrated. Then the actual HP production of the engine depends on the temperature of the intake, water and oil temperature and probably even more.
I wonder what the total margin of error is? Can you even reproducibly measure power within 5% taking all correction factors into account, assuming one dyno is for instance in Denver and the other one in San Diego?

You bet, probably within 1%

Yes the power output depends on the temps in the engine. In fact for every10 degrees of water temp there is 1% gain. That's hotter guy's. The hotter the more power, NASCAR engines run about 220f. They can go up to 260f before they get into trouble. You get 3 degrees extra temp before boiling for every psi over atms. Meaning for a 25lbs cap the coolant say water will boil at 212+75 or 287f. Add some antifreeze and it goes up from there. But antifreeze is not as good of a coolant as water.

You can make water a better heat transfer medium by adding a "Wetting" agent. This breaks the surface tension of the water and lets it get closer to the metal surface. If I remember right it adds another mole of oxygen and therefore becomes more corrosive.

So this is why racers monitor the temps closely. It's always faair because all race cars are in the same condition at the same time. Now the team that can adjust their engine for conditions has an edge.

You bet, probably within 1%

Yes the power output depends on the temps in the engine. In fact for every10 degrees of water temp there is 1% gain. That's hotter guy's. The hotter the more power,


not this car Richard- Racing Beat's Jim Mederer has shown with his ecu test bench that if the car see's coolant temps rise above a limit set in the pcm the car starts pulling timing. the longer its stays at that higher temp or the more the temp goes up the more timing is pulled. then it starts lowering your rpm limit and other things to try to get the temp back where it wants it. that limit is well below boilover.

OK Not this car. The rotary I have come to find is already running hot. This is something I must think about. Since there is so much heat in the exhaust why is there no moore heat in the water? Or is the water doing a balls out job just trying to keep the thing from welding itself together now?

dont forget - oil is doing alot of the cooling work. hence why we in the states have 2 oil coolers stock.

Yes ant that is one of the reasons I'm trying to find my old materials professor. He has developed coatings for the hot section of APU's. I want to see if these can be applied to the exhaust ports.

not this car Richard- Racing Beats' Jim Mederer has shown with his ecu test bench that if the car see's coolant temps rise above a limit set in the pcm the car starts pulling timing. the longer its stays at that higher temp or the more the temp goes up the more timing is pulled. then it starts lowering your rpm limit and other things to try to get the temp back where it wants it. that limit is well below boilover.
But that doesn't mean that the engine couldn't produce more power if it would run hotter without affecting its timing. If the rotary engine could be built out of some exotic ceramic material it could probably run hotter and increase its power and efficiency.

For instance silicon nitride (well if it just wasn't that expensive to manufacture, there's certainly enough silicon and nitrogen around).
http://www.azom.com/details.asp?ArticleID=53

This talk about comparing different dyno's... I have a couple of views on this. First and foremost, I don't think the primary purpose of a dyno is to compare power outputs between different dynos. The primary use is to compare changes made to a daseline - readings taken from the same machine.

The dyno is but one of the tools used by the tuner. Yes - a tool. There are lots of variables. And one car will make different power on the same dyno on different days. I have seen so many dyno-war threads, it is silly.

Dyno Dynamics try to have a standard testing sequence and accredited testers for what they call the "Shoot-out" mode, to try to make for an even playing field. It has some merit, but the cinical amongst us would see it as a clever way to try to create demand for the product.

Strain gauges. That sounds a bit like something off the ark! All the modern dyno's I have experienced in Australia (chassis and engine) are electronically controlled, and use electromagnetic "brakes" to measure the power.

Cheers,
Hymee.

This talk about comparing different dyno's... I have a couple of views on this. First and foremost, I don't think the primary purpose of a dyno is to compare power outputs between different dynos. The primary use is to compare changes made to a daseline - readings taken from the same machine.

The dyno is but one of the tools used by the tuner. Yes - a tool. There are lots of variables. And one car will make different power on the same dyno on different days. I have seen so many dyno-war threads, it is silly.

Cheers,
Hymee.

some of us have been preaching that for years on this forum , thanks Hymee:)

Hymee, you have your componants confused, The braking of the dyno can be done with many types of resistance. Most engine dynos use the "water brake". Some use Eddie Current. That's a wonderfull thing as you get to sell the electricity back to the power company.

Now the strain gauge is just a link between the engine and the frame. It electronicly sends the info to the computing componant which in turn converts it into a number we use called Ft/lbs. Then utilizing this number and the one it gets from the speed sensor gives us the HP. It can compute SAE readout or Std corected. Just tell it which you want.

In the case of the Superflow it reads fuel flow and airflow by turbine. Using numbers you put in it gives A/F by weight. It uses direct not corrected HP to come up with these answers. It then gives you BSFC and BSAC. Brake specific air and fuel consumpsion.

You see that it needs you to weigh the fuel by specific gravity (a hydrometer or by weighing 100 cc's on a scale) and air by RH, temp and baro in inches of Hg.

That is the only way you can get the proper corrected figures. I can't picture the chassis dyno operators going through all those hoops. So if you (Hymee) say that you see higher numbers even after correction between cold and hot days on your dyno runs then this is the reason. ;) To do it right you need to treat it like you are conducting lab tests for atom bonbs. All the details must be factored in.

As I said the formulas have been accepted around the world by race engine builders and car factories alike. Only on the RX 8.com club forum have they been called suspect. But then there is the mom who looks at the army on parade and says "look my son is the only one in step". How can you argue with her. :rolleyes:

Now I'm very carefull not to argue with people who hold decades old practice in their hand. Why? Because there was this saying carved into the entrance of one of the many academic building from which I was evicted. "Where a little knowledge is a dangerous thing" ;)

Richard,

I'm not making an argument with you. All the "modern" engine and chassis dyno's I have seen in this land use the electro magnetic brake thingy to measure the power dissipated it. No strain gauges anywhere. And from the power the torque is derived by a simple calculation, as you know, the only other factor being the RPM.

The power measured is determined by the relationships between the resistance, voltage, current.

And the air/fuel ratios are read from a very accurate O2 meter. And the Dyno cells typically have a weather station on the wall, so the SAE correction factors can be entered fairly simply.

Perhaps I have been lucky to see modern stuff! The most common ones around here are DYNOLOG(IC) and DYNO-DYNAMICS.

http://www.dynologic.com.au/index.html

http://www.dyno.com.au/

Cheers,
Hymee.

That dyno dynamics engine dyno looks nice.

But, But, But Hymee, what do they use for load mesurment a "load cell"
That is the same sort of device as a strain gauge. not using the electricity developed by the electro magnetic brake. The load cell can work with a 5 volt input same as strain gauge input.

Some load cells are buttons, some are s shaped thingies.
They can be made to take enormous amount of weight.

So how much are these things compared to the Superflow??

Nighty night, Thecrankyoldbastard :cool:


Edit) oh yea, they take baro and RH and temp automaticly.

BUT, they say they correct to SAE. Now if that's the case what do the systems used over here cor to. anyone know??

I remember a few months back someone posted a little table showing simple boost curves of different supercharger setups. It looked something like this.
Rpm Boost Pressure
Centrifugal
Positive displacement
axial flow


The numbers were filled in obviously. I was wondering if someone could post that again, I can't remember exactly how it went, but I think the centrifugal was exponential in nature, the PD was full boost from 0 rpm but I dont remember how the axial flow went. Thanks to whoever posted this before and to whoever can help answer my question.

(it may have been me)

This is the way it works...

Centrifugal - boost is roughly proportional to the square of impeller speed. 2 x RPM = 4 x boost.
This means, that for a blower designed to give 12 PSI boost at 9000 engine RPM, it will give 3PSI at 4500 RPM.

Axial Flow - Roughly linearly proportional to blower speed. 2 x RPM = 2 x Boost.
That means at the same design of 12PSI boost at 9000RPM, we get 6 PSI boost at 4500 RPM. So at 4500 RPM, you got twice as much boost as the centrifugal.

Positive Displacement - roughly constant boost at all blower speeds. 2 x RPM = same boost :( . Also mean 1/2 RPM = same boost :)
That means for the same design parameters of 12PSI at 9000RPM, you will get 12PSI at 4500 RPM. And 12 PSI at 2000, 4000, 6000, 8000. So at 4500 RPM you got twice the boost of the Axial flow, as 4 times the boost of the centrifugal.

The advantages of the Centrifugal are compactness. It is also what a turbo uses for it's compressor - the difference being the shaft speed (hence boost) is more or less based on engine demand (exhaust pressure), not engine RPM. You can also get higher boost pressures, so you can get more max HP. But you have to wait for it!

The advantages of the axial flow is it is fairly compact, and apparently takes less HP to spin, and puts less heat into the charge. Hence you get more useable power. Richard showed me some graphs on the axial flow for the heat it puts into the charge. And also how it made more power than other other systems for the same PSI.

I have charts showing lab tests for the HP required to drive a twin-screw, and also how much heat it adds. You cant get away from adding heat to air when you compress it. It is just a matter of physics, no matter how efficiently you do it. After all, that is how a diesel works, right? It compresses the air so much it gets hot enough to ignite the fuel.

Bring on forced induction!!!

Cheers,
Hymee.

You've got the explanations for PD and axial confused with each other.

(it may have been me)

This is the way it works...

Centrifugal - boost is roughly proportional to the square of impeller speed. 2 x RPM = 4 x boost.
This means, that for a blower designed to give 12 PSI boost at 9000 engine RPM, it will give 3PSI at 4500 RPM.

PD - roughly constant boost at all blower speeds. 2 x RPM = 2 x Boost.
That means at the same design of 12PSI boost at 9000RPM, we get 6 PSI boost at 4500 RPM. So at 4500 RPM, you got twice as much boost as the centrifugal.

Axial Flow - Roughly linearly proportional to blower speed. 2 x RPM = same boost :( . Also mean 1/2 RPM = same boost :)
That means for the same design parameters of 12PSI at 9000RPM, you will get 12PSI at 4500 RPM. And 12 PSI at 2000, 4000, 6000, 8000. So at 4500 RPM you got twice the boost of the Axial flow, as 4 times the boost of the centrifugal.

The advantages of the Centrifugal are compactness. It is also what a turbo uses for it's compressor - the difference being the shaft speed (hence boost) is more or less based on engine demand (exhaust pressure), not engine RPM. You can also get higher boost pressures, so you can get more max HP. But you have to wait for it!

The advantages of the axial flow is it is fairly compact, and apparently takes less HP to spin, and puts less heat into the charge. Hence you get more useable power. Richard showed me some graphs on the axial flow for the heat it puts into the charge. And also how it made more power than other other systems for the same PSI.

I have charts showing lab tests for the HP required to drive a twin-screw, and also how much heat it adds. You cant get away from adding heat to air when you compress it. It is just a matter of physics, no matter how efficiently you do it. After all, that is how a diesel works, right? It compresses the air so much it gets hot enough to ignite the fuel.

Bring on forced induction!!!

Cheers,
Hymee.


Thanks a lot Hymee :) I think I got it now, thanks for replying so quickly.

You've got the explanations for PD and axial confused with each other.
Holy fat fingers batman, how did I manage that? I'll fix it!!!

Thanks a lot Hymee :) I think I got it now, thanks for replying so quickly.

Sorry if my little mistake confuses it even more!! But what you said the first time in your question is correct. I just tried to expand.

Centrifugal = "exponential" boost
Axial Flow = "linear" boost
Positive Displacement = "constant" boost

Thanks again RG for pointing out my error. I should have checked it properly!

Cheers,
Hymee.

Sorry if my little mistake confuses it even more!! But what you said the first time in your question is correct. I just tried to expand.

Centrifugal = "exponential" boost
Axial Flow = "linear" boost
Positive Displacement = "constant" boost

Thanks again RG for pointing out my error. I should have checked it properly!

Cheers,
Hymee.
Oh, OK. Sounds good, everyone's human so you're forgiven Hymee. :D

Okay another daft question from a really keen scotsman.
Firstly the 3 posts that I have posted so far dont actually seem that enthusastic about this project.
I would just like to say that RP and everyone else involved with this project has done an excellent job so far in designing this supercharger.
I am eagerly awaiting the finished product.
Only one thing, when thinking about the engine management system for this project please forget about the canzoomer module.
I am sure 99% of canzoomer customers across there are delighted with his work and the power increase that they got. As for myself the unit dropped my total horsepower by 20hp running with 0 map. From this conclusion my self and two tuning garages decided that is was unsuitable for the UK Spec RX8.
The UK spec runs with the larger spark plugs as standard equipment.
As for RP's comment about better fuel for more power, could you please explain a bit more what you mean by "better fuel". I make the stuff across here for a very small company called BP.
Our standard fuel is RON95 with the better fuel being of Ron 97-98.
I know from previous trips to the states that you guys can run from about, please correct me if I am wrong, 86 - 95.
So in theory for the better petrol I can be running about 101 octane level across here. Never tried it yet with the RX8 but the old nissan almera loves the 101 octane blend. By the way to get the 101 I have added octane boost which is about 107 octane, 2 bottles off.
Now that that is out of the way, will porting the rotary engine in association with the supercharger make a difference, or will the supercharger design already be at the limit. Is this supercharger going to be slightly over designed for future expansion is probably the question that I am trying to ask here.
:cool:

This question may have been answered before in this thread, but honestly I have forgotten 2/3'ds of it already.

But by "linear" boost increase, does the boost above atmospheric start at 0 at 0 rpm, or at idle, or somewhere higher in the rev range?

Also, how does linear vs constant boost translate to driving characteristics of the engine?

Also, how does linear vs constant boost translate to driving characteristics of the engine?
A constant boost compressor will give you more low end torque and less high end torque (or in other words less power) assuming both compressors deliver the same amount of pressure at maximum power (well, if the constant boost compressor is indeed less efficient.)

An ideal engine has a constant torque level over a very large speed band. I guess you could call that in general most user friendly, however it might also be a matter of taste, some poeple might prefer peaky engines because it gives them more satisfaction for whatever reason. A compressor with a constant boost is more likely to deliver constant torque.

I didn't know BP was a "very small" company. Or were you kiding?
What I had said was the lower the grade fuel you can run without getting into detonation the more power you will make. The more MPG also. The reason is that "octane" is a messure of resistance to detonation. This will slow the burn down. The additive takes space away from real energy producing fuel. I doubt you can get anything running 101 fuel. For that matter you could try NASCAR fuel at 104 and make less power yet.
So a detonation resistant design chamber can run cheaper gasoline. Or it can have higher compression ratio or more boost. This is the condition we have with a good four valve head. IE: Cosworth. Which is the grandaddy of all the chambers we have out there now. They are all evolutions if not direct copys of the Cosy.

How the rotary relates to this I have yet to learn. Maybe RG can comment on that.


Now porting will help with a blower possably more then without. That assumes it was done properly. Next we should understand that manifold pressure is resistance to flow. Therefore a ported engine may show lower man press but will make more power. That is your goal, more flow throgh the engine. NOT more pressure.

The AFS will start making pressure at off idle if the throttle is open. Thing is it shouldn't be. In the Rx 8 case it will not be because it is fly by wire and you can have your foot to the wood and it will only open the amount programed into it.

If it were a perfect world the torque curve would be like an electric motor, full torque it idle. I don't think you could use a powerplant like that with the sort of chassis we use. At least with the sort of driving style we are used to.

Yes the supercharger will have excess capacity. I would be the best engineer in town if I could design a blower to be just perfectly matched to peak at the same time as the engine. THe only insurance you have of not running out is to design it over. Remember what I just said, if you get more flow the pressure will go down. Don't equate this with a lack of capacity.

Hope that helps, Richard

Or were you kiding?

Is the Pope a Catholic?

Yes, But is he Polish? :confused:

RP,

I did reply to your post about the Materials Prof. I don't know him. Nor, have I heard of him. However, this is a bit out of my experience level. My focus has been in the performance world not so much in the materials world. Although I have run across some interesting tid bits from time to time.


Wildcard,
You are absolutely correct about the turbofans. The F111 was the first turbofan engine placed in a fighter application. In fact, there was tremendous discussion about not letting this airplane fly in Vietnam because they didn't want the potential for the technology to fall into others hands. All US fighter engines since have been turbofans (albeit some have been called leaky turbojets because of their low bypass ratios 0.1 - 0.4). Most commerical gas turbine engines used low bypass ratio turbofans prior to the TF39 used on the C5A. They had bypass ratios in the 1.5 to 2.5 range. The TF-39 had a bypass ratio of approx 8 but today most of the high bypass ratio engines have ratios in the 5-6 range.

Hymee,
As to the question about the thrust production of high bypass versus low bypass ratio engines. Here's one way to think about this. Both engines could be considered to have a fan exhaust stream and a core exhaust stream. These may exhaust through one nozzle or they may exhaust through seperate nozzles.

In general:
The high bypass turbofan with a bypass ratio of 5-6 has 5-6 times as much air going through the fan exhaust stream as through the core exhaust stream. The exit velocities are not the same because the core exhaust is much hotter than the fan exhaust. However, the fan stream generates the predominate thrust because of the fact that it has 5-6 times the flow as the core stream. Gas velocity differences do not come close to making up the difference.

As the bypass ratio comes down, in general, the averaged exit velocity increases (core and fan stream) so the specific thrust increases (thrust/lb of airflow). However, this happens at the expense of more fuel consumption. In this case, more of the thrust comes from the core stream and less comes from the bypass stream. I think this is what you were trying to say earlier.


globi
We've played in the silicon nitride world for some time now. These would be great materials if they weren't so brittle. They have very little fracture toughness so when you hit them with even small impulse loads they fracture. The key will be finding proper matrix materials to act has binders to allow these materials to work. This is going to happen in our lifetime. I'm just not sure when. When it does, there are going to be performance improvements for everyone. It's may provide some revolutionary changes.

Jon, how do you know I was speculating? ;)

And It's been a few days and I'm still here. :p

Thank you turbine_pwr, your answers are as always very informative and authoritive. :cool:

For those interested. The A160 is an unmaned helo. Still in development I have the website, I'll get it up later. (Did I just say that?) I'll post it later. That's better.

A Boeing project.

More efficient and 'simpler' jet propulsion?
http://www.crd.ge.com/01_coretech/pulseDetonationPropulsion.shtml
http://www.grc.nasa.gov/WWW/AERO/base/pdet.htm

Apparently Richard is having a problem getting it up. :eek:

A160 link from Google:

http://www.globalsecurity.org/intell/systems/a160.htm

Apparently Richard is having a problem getting it up. :eek:
I don't think Richard will appreciate that comment too much :p

Silly question.. Is it possible to start out with like 20 psi and gradually drop the boost up til redline?

High boost at lower rpms needs less fuel and generate less heat than the same boost at higher rpm. Hence you could get some insane lowend gains without compromising the engine at higher rpms..

Theoretically that is possible. The hard part is going to be finding a turbo that has it's efficiency range based on this and also finding one that will spool up to these numbers at a low rpm but still not be a restriction to power at high rpms. The idea is sound but the actual ability to pull it off in practice may be limited.

Theoretically that is possible. The hard part is going to be finding a turbo that has it's efficiency range based on this and also finding one that will spool up to these numbers at a low rpm but still not be a restriction to power at high rpms. The idea is sound but the actual ability to pull it off in practice may be limited.

I was more thinking about SC. Not that I know a lot about sc, but from what I gather you should be able to have full boost at a lower rpm.

I was more thinking about SC. Not that I know a lot about sc, but from what I gather you should be able to have full boost at a lower rpm.
These SC's will do exactly that:
http://www.boosthead.com/home.php
:)

These SC's will do exactly that:
http://www.boosthead.com/home.php
:)

For 15 seconds.. hehe

For 15 seconds.. hehe
Well to be fair: 15 seconds every 10 minutes. (Still better than driving around with an empty N2O bottle in the trunk).
Here's the diagram you've been looking for:
http://www.boosthead.com/installation_docs/doc20.gif

Wouldn’t it be possible to make some sort of reverse gearing where the higher the rpm the slower the sc spins? It will of course have more parasitic loss at lower rpms, but the characteristics of such a sc would rock insanely. Wonder if the drive chain would be able to handle the “abuse” of massive boost at low rpm, but that is another story.

Anyone have a compression map for the axial flow sc? At what rpm is it possible to gain 20+ lbs/min?

You might want to be looking for a Twin Screw SC if you are going to try this. They can produce max boost at idle and then you could just tune it down as the revs increase. A Roots SC can do that too, but I doubt you would be in the efficiency range of a Roots if you were going to try this.

This hps curve would give me wet dreams. In fact, it allready does.

(red = new, black = stock rx8)

You might want to be looking for a Twin Screw SC if you are going to try this. They can produce max boost at idle and then you could just tune it down as the revs increase. A Roots SC can do that too, but I doubt you would be in the efficiency range of a Roots if you were going to try this.

How can you "tune it" down?

twospoons, doesn't a Ford Mustang or a VW Golf TDI have sort of that red curve?

Mustang is somewhat similar, but it doesn't go as fast up and stops at 5.5k :)
VW tdi looks like a heart beat. Very narrow powerband and dies horribly.

Somebody might want to double check this.

Horsepower needs to rise as rpm's rise in order to keep acceleration linear. The goal should be a flat torque curve.

VW tdi looks like a heart beat. Very narrow powerband and dies horribly.

Somebody might want to double check this.

Yeah but a chip (such as Upsolute) can really help that engine out.

How can you "tune it" down?

My guess would be to possibly get a sort of boost controller or get a weird gearing setting. It just seems that the best solution for something you want to produce max boost at low rpm is that you would be least overspending if the boost level didn't naturally increase.

What you want is a "Motor" vs an "engine". They for the most part give max torque at stall speed. Like electric, hydrulic, vacuum etc.
I don't think this is compatable with chassis dynamics as we know them. Or driving in a high performance manor with said chassis.

Granted no one has had to think of new chassis designs to work with this type power curve. Still hp has to have the componant of speed an distance added to torque. But ploting that curve should give a linear line. I have never tried it. You guys need the mental masterbation more then I. :rolleyes:

So that's why we turn to the forum instead of women *smacks forehead* ;)

I don't know if I want to touch that. :eek:

I do know that as much as I love the forum, Women are better and I love them expotentionaly more.:D Even if they are more trouble. :rolleyes:

So what kind of chassis do you think handles this motor? Because I have one :)
Wouldn't you love to have that kind of power curve in an RX8? Just cut everything off at 10k RPM.

looks like we better get an electric motor in there!

Ajax, I don't know how you came up with those plots but a good test is that torque and hp must cross at 5252 rpm.

Note that those plots are for a .07hp motor!
Power curve is in watts and peaks at about 55 watts (746 watts per hp if you want to do the math, anybody).
The motor in question seems to be running on one volt (40 watts at 40 amps, from the curves).

Horsepower needs to rise as rpm's rise in order to keep acceleration linear. The goal should be a flat torque curve.

F=ma. If force is the same, acceleration is the same. Hence a flat hps curve will lead to a linear increase in velocity. (If you take air drag out of the equation)

I don't know if I want to touch that. :eek:

I do know that as much as I love the forum, Women are better and I love them expotentionaly more.:D Even if they are more trouble. :rolleyes:

Don't worry about it. Women are better.

I bet 44 will be disappointed by that comment though :(

HEY!! :( :D i can ban you ya know hehehej/kj/k:)

So what kind of chassis do you think handles this motor? Because I have one :)
Wouldn't you love to have that kind of power curve in an RX8? Just cut everything off at 10k RPM.

or run at a constant 13KRPM with a CVT :) I'd run one in an rx8 .... but it'd have a lexan bodyshell ;)

Just hit me, I'm a little slow. Lexan body, DAH! Great hint. Slotcar. :D
I knew there was something strange when ajax wanted a .07hp motor.

F=ma. If force is the same, acceleration is the same. Hence a flat hps curve will lead to a linear increase in velocity. (If you take air drag out of the equation)
torque is a force, not horsepower.

it's one of the mods i have in one of my 4 1:10 RC cars.

I think that's the plot for my 8x4 (8 turns 4 winds).. One of the 2 fastest I own.. It will literally tear the tires off the rims if you drive it on pavement.

EDIT: Oh yea, it's running a slipping diff. The whole car is titanium linkages and carbon fiber chassis. Probably weighs about 5lbs with a battery. 0-60 in 1 second :b

Why on that scale would you use titanium? Aluminum is lighter and will be strong enough. It is easier to work with and cheaper.

Why on that scale would you use titanium? Aluminum is lighter and will be strong enough. It is easier to work with and cheaper.
Titanium for linkages is pretty much imperative when you drive offroad. The shock you take on an impact is incredible. Aluminum linkages would bend under the force, whereas titanium just takes a beating and doesnt think twice about it.

We don't use anything aluminum that is exposed to stress. My tranny screws are aluminum and some of the standard mount screws are. That's it. Everything else is stronger material.

I don't have any on road vehicles. If I did, I would totally agree with you that aluminum would be the way to go for most of the parts. I dont actually aluminum screws because they wear too much when you do a rebuild. The heads strip far too easily and I like to tear down and rebuild a tranny in a matter of a few seconds.

As far as titanium goes though, I have titanium linkages and kingpins on almost every offroad RC I own. Some of them have more TI than that. Yea, it is expensive, but it's easily justifiable vs the standard parts.

Ajax, just curious since I've never heard of carbon fibered RC cars. Is there a website?

Alot of R/C car chassis are made out of carbon fiber. When I did it as a kid they were graphite chassis but close enough.

Alot of R/C car chassis are made out of carbon fiber. When I did it as a kid they were graphite chassis but close enough.
Graphite is and was very popular but no longer for offroad. I had graphite shock towers for a while and i snapped them after 1 race. They were just too brittle.

As far as websites go, both pro teams losi and associated use carbon fiber for the chassis.

Losi: http://www.teamlosi.com
Associated: http://www.rc10.com

Back on topic you guys. It's Airplanes remember? ;) ;) :cool:

Everything flies Richard. Some of them need to be going faster than others to do it.

I know that, I once flew a Formula Atlantic car in Newfoundland, right into a traffic light at about 140 mph. When your driving and you realize that the steering , the brakes, and throttle have no effect on the cars direction, your flying. :eek:
And it's probably going to hurt. :(

How about really getting on topic and talking about RP building an Axial Flow for the 8?

:eek:

yeah really...my RP shifter has me all excited about the AFB!

I know that, I once flew a Formula Atlantic car in Newfoundland, right into a traffic light at about 140 mph. When your driving and you realize that the steering , the brakes, and throttle have no effect on the cars direction, your flying. :eek:
And it's probably going to hurt. :(
140mph :eek: How bad was the medical bill? Glad you made it, otherwise no blower for me :p

Scocialized medical care in Canada, all I paid for were the crutches. :rolleyes:

When your driving and you realize that the steering , the brakes, and throttle have no effect on the cars direction, your flying

The reminds me of a great quote I read once - sorry I don't know who to attribute it to...

A wheel that is not rolling has no directional integrity

Cheers,
Hymee.

Now I can start posting again - after saving something good up for my 3000th ;)

epitrochoid:

Just a note for purities sake: Torque is a moment not a force. It is a force acting on some moment arm. Could be a small force with a big arm or a big force with a small arm.


In the electric motor arena - the government is looking at electric drive systems for a number of new ground vehicles. These systems produce a tremendous amount of low end torque. However, since batteries can not be used for long term propulsive effort, there is still a requirement for a diesel, gas turbine, otto cycle system, rotary or some other type of prime mover that will then drive generators. These systems are not too far removed from the trains dragging stuff around the world.

Hymee,
Congratulations: 3000th post. Seems like it belonged in one of your own threads though. Sigh

Holy posts Batmanbastard, I never noticed your contribution has been going on that long. :D If you had a dime(US) for every post, you could buy yourself a shifter. ;)

Hymee,
Congratulations: 3000th post. Seems like it belonged in one of your own threads though. Sigh

Thanks. It does have it's very own thread! go have a look at this: http://www.rx8club.com/showthread.php?t=51828 :)

Cheers,
Hymee.

epitrochoid:

Just a note for purities sake: Torque is a moment not a force. It is a force acting on some moment arm. Could be a small force with a big arm or a big force with a small arm.

right but, a moment is more of a "force" than horsepower, and since all the "arms" in our car are more or less a constant (spare gearing), all that changes is the force.

flat tq = linear acceleration

Turbine_pwr, That is the system the navy uses on ocean going tugs. THey have, at least on the one I saw, four big engines driving generators. Under low load, like not towing, they just run one engine. The big deal is that they have very fine adjustment of whatever power they need. This ship had one huge prop that turned slow. At least that is what was explained to me.

Thinking about it now I realize that they probably had cavitation if they applied to much power or tried to get to many rpm wwith a smaller prop.

One huge prop turning slowly will grab the water better. So to get it to turn while towing a destroyer they need the power. They can get the best RPM at all times if they can vary the power without raising the shaft speed because they had to raise engine speed that is conected to the shaft.

Richard,

Good points. But don't forget the gas turbine powered ships either. We have a number of engines that are providing motive power for various shipboard applications. One of the more recent was the TF50A engine in the LCAC. Kind of a neat vehicle.

http://www.fas.org/man/dod-101/sys/ship/lcac.htm

Note those HP numbers

Hymee
Nice post. When are we going to be able to buy the "sCANalyse Live" system? and dare I ask... am I going to have to sell one of my kids to buy it? By the way... I'd consider letting you have one cheap, two cheaper, and if you're willing to take all three I might even be willing to pay. Note: They are at very productive ages 19, 20, 21.

For those growsing about the weather. I do live in sunny Az. As usual, it's been sunny and in the sixties for the last few weeks. Albeit, we've had a wet winter. I think something like 2-3 inches of rain in the last 3 months. We're still bailing

ep
I'll let you slide on the torque thing. Just didn't want anyone getting the wrong impression (wry smile).

By the way... just to have some fun. Back a couple weeks ago, there was an interesting discussion about the speed of sound. Some bad stuff was passed along during this discussion.

1. Speed of sound = SQRT( gamma * R * gc * Temp) where gamma is the ratio of specific heats Cp/Cv, R - the specific gas constant, gc - getting the correct units for us old hat fuddy duddies, and Temp is just that (Temp in absolute units) - in short hand this is Richards 49 *SQRT (T ).

However, assuming we are using an ideal gas (yes air qualifies) . Then P = rho * R * T.

In which case
2. Speed of sound = SQRT( gamma *P / rho ), Which shows that the speed of sound is also a function of the pressure and density of the fluid your working with. This of course is why when you breath Helium (not recommended for long term longevity) and talk, you end up with a squeeky voice. Helium is a small molecule (ie low density fluid) and the speed of sound changes accordingly... (the Micky Mouse Voice)

Sorry to be such a anal retentive bastard but I don't want anyone to fail thermo, heat transfer, or fluids because of our contributions. Snicker... Snicker

Which shows that the speed of sound is also a function of the pressure and density of the fluid your working with.
You've got me thinking about how this pertains to the Renesis or any other engine for that matter. In the Renesis, part of the S-DAIS intake sysem is the VDI system. This is a valve that opens at a higher rpm to retune the intake manifold to a higher point so that the powerband stays stronger for longer. It relies on the pressure wave of the intake port on one rotor closing and it's interaction back through the manifold to the other rotor where it's effect is seen as a positive pressure wave that helps ram more air into the port right before it closes. The longer the runners, the lower the benefit in rpm. This wave travels through the intake manifold at the speed of sound. The question as it pertains to your statement is will this effect be changed with the addition of forced induction? Might it be necessary to change this valves opening point to a different rpm because the effect is no longer where it would be on a naturally aspirated engine? Your statement confirms something I have always thought about but now I'd like to know if the intake tuning sees this change.

Resonant intake tuning is useful in a NA engine for the very reasons you stated (slight pressure increase at the intake port). However, it is usually not included in a blown engine -- the friction losses in the runners are more than the tuning gives, and even without them the gain would be miniscule compared to the mechanical boost that is being applied. So blower kits usually toss the tuned intake tubes out with the trash.

Note: I had a '59 Plymouth Sport Fury with a 383 cu in B block that had the long cross-ram manifolds on it for a while. No, that wasn't the way Chrysler Corp. made it!

Richard,

Great to see you’re still making these jewels. Seems like I had a fancy four-color brochure offering your Latham kits for Camaro/Corvette around mid-80s? Does that sound right? Or maybe it was a magazine article. Anyway, I remembered them from the sixties and was impressed at your efforts and by your product… figured I’d have one on something some day. Then I didn’t hear anything about Latham SCs… but always thought about them whenever I thought about forced induction.

I saw a rat rod a couple of years ago in traffic near Indianapolis Raceway Park… it had a flathead Ford engine with a Latham blower, so I tried to get turned around to chase him down and see if he knew anything about the current availability; got hung on stoplight and lost him… I was very disappointed.

Just for the heck of it I googled Latham yesterday, and read this thread straight through except for a couple hours of sleep. Impressed all over again. Good luck with this latest iteration. :)

Found another axial flow Latham picture on the internet.

I’m still confused about the axial flow compared to positive displacement sc. Hymee stated:

“Axial flow – linear. 2x rpm = 2xboost”
“Positive Displacement – constant. 2x rpm = same boost. ½ rpm = same boost”.

Then RG said;

“You've got the explanations for PD and axial confused with each other.”

Then Hymee corrected himself, but just reiterated what he stated earlier:

Centrifugal = "exponential" boost
Axial Flow = "linear" boost
Positive Displacement = "constant" boost


So, which is it?

Is the axial flow sc PSI a function of the rpm or is it constant regardless of rpm?

*ponder*

I think you're confused because Hymee went back and edited his post for correctness? It looked right by the first time I saw it too...

jds

I think you're confused because Hymee went back and edited his post for correctness? It looked right by the first time I saw it too...

jds

I think I'm just confused :P.. That makes sense yes. Thanks.

Before Hymee corrected his post, it said that centrifugal was a linear and axial was an exponential. That's backwards. Now it reads correctly.

I noticed that some cars with SC installed from factory have the ability to disengage the SC when cruising. How hard would it be to implement something like that with a bolt on kit?

“The Eaton superchager in a Mercedes-Benz application showing the magnetic clutch used to disengage it for cruising efficiency.”

I noticed that some cars with SC installed from factory have the ability to disengage the SC when cruising. How hard would it be to implement something like that with a bolt on kit?

“The Eaton superchager in a Mercedes-Benz application showing the magnetic clutch used to disengage it for cruising efficiency.”

With the Eaton (or any other positive displacement SC) stopping the rotor means stopping air flow completely. Mercedes must, therfore, bypass the blower completely with the induction system when the clutch is disengaged. Virtually all the other Eaton installations simply recirculate SC outlet air back to the SC inlet when boost is not called for... in some of them this passage is built right into the blower itself. When recirculating, the blower uses virtually no power. Not sure why Mercedes added the complexity.

As for a clutch on the axial flow... I don't think it's pumping as hard at low RPMs as a roots is, so there would be far less benefit to disengaging it... and I'm not sure how well, if at all, air can flow through the axial flow if it's not spinning.

Speaking of recirculation, can you just oversize a non-PD supercharger so it has, say, 8psi at 3000(engine)RPM, and then variably bleed air (pressure) from its outlet back to its inlet (ECU controlled, of course) to keep the manifold pressure from going any higher as RPM goes higher? The same bleed circuit could be used to "unload" the power consumption during crusing, as the Eatons do.

Can this type of recirculation be used with an axial flow SC?

you could, but you'd still be stealing power from the crank to drive the blower thus creating a huge ineffeciency

you could, but you'd still be stealing power from the crank to drive the blower thus creating a huge ineffeciency

I don't think so... Eaton claims 0.3 hp is used to turn their (~Roots) SC when it's recirculating... a screw type (Lysholm, Autorotor, Whipple), on the other hand has actual internal compression, so it would still be doing work. The axial, since it isn't doing internal compression, would not use much, if any, power.

Let's see if I can get all this answered. With the AFS if you remove the belt it will spin quite happily along as you drive. In fact it will take several seconds to stop after you shut it off. The axial DOES have internal compression. The thing is that when used as a draw through it uses almost no power when the throttle is not open. If the air is thin it doesn't compress anything so uses no power.

Recirculation is not all that good as you return heated air to the intake. Now I know someone is going to tell me that the air will expand in the intake and the heat will go away. Well this might sound good but you can't change conditions without paying for it, some energy is lost.

Why does Mercedes add complexity?? Because they are German. That's why they lost the war, they built everything so complex, heavy duty and rebuildable when it should have been built as a throw away.

I don't think so... Eaton claims 0.3 hp is used to turn their (~Roots) SC when it's recirculating... a screw type (Lysholm, Autorotor, Whipple), on the other hand has actual internal compression, so it would still be doing work. The axial, since it isn't doing internal compression, would not use much, if any, power.

The axial does have internal compression through each of its stages.

Internal compression makes for higher adiabatic efficiency. That is why a twin-screw is more efficient than a roots.

Cheers,
Hymee.