the ecu controls all..... do you not know that.... it is not different in the uk....

yes flash tuning will do what it will do. but no one is there yet..

beers

 

Wow I missed a lot.. RP I want to be hulk with a tad of shreck. ha ha. whole weekend I dreamt of that SC. I even called my G.F. SC in the middle of the action.. I had a lot of explaining to do...after she asked me [who the hell is "super charger"]

Thank you RP. I won’t hurt a fly…never been in a fight my whole life..


ohhhh Jedi54 and I will be incharge of lunch...sorry jedi54 we have to get in which ever way we can..

 

still nothing for you rx8 guys?

 

I wouldn't say this thread is nothing, nor many of the others. The RX-8 is just an exercise in patience. It took a while for RX-7 aftermarket support to get going also. People that are newer to the RX-7/rotary market are spoiled by the mass aftermarket support for the 7, that once wasn't there in the FD's initial years.

 

They do have negatives, as does a supercharger, but I don't know anyone that want to heat all the air going into their engine an extra 75 degrees. Run a renesis on a 60 degree day and run it on an 80 degree day and there is a perceptable difference.

 

His point was that if you use an intercooler that has say a 1.5 psi pressure drop but you are only running 6 psi total, that extra 1.5 psi that the blower needs to produce to overcome that loss will also create more heat (which gets cooled down by the intercooler) and that at low levels this can potentially offset or cancel the gains of having the intercooler. He knows that there is a point above which you need an intercooler. You just don't always need one depending on what you are doing. For his needs, any benefit that one may provide could be small and since the throttleplate is before the blower he didn't want to affect throttle response. Remember this isn't a kit designed to give real high numbers. It's made to a nice streetable system that provides a nice gain over stock. Much like Pettit's goal.

 

Ahh yes, but if the 80 degree day you were running at 2000 feet below sea level, which would be the faster run???
What if on the 60 degree day you had to draw your intake through a restriction such as a radiator which run would be faster then?
And what if you had been idling in traffic before the run and radiator heat had transfered to you inlet radiator? What temp would you intake air be then?

And how good does your bank account look with the $1000 deduction. Next how much fun is it working on the car with all that extra plumbing runing everywhere. What if your extra HP had to pull around all the extra weight? Which car would feel faster then?

All that isn't to say that an AC wouldn't be helpfull under some conditions. Like real race conditions with high boost. Real race being the active words.
I want to say "I've been there and done that" but I wouln't.

 

We got to that one at the same time.

 

Yes, and as you've pointed out before I type a little slower then you!

 

There is some theory that a hotter charge of air produces less condensation of the gas being introduced and thus makes the charge more efficient resulting in better gas mileage and more power for the same density of air.

John

 

Assuming there is no pre-detonation form the hotter induction temp

I could see how a hotter intake charge with the same mass flow as a cool one would effectively cause the fuel to atomize more; getting a better burn creating higher combustion pressures. Plus adding an intake charge again with the same mass as a cool one but at a higher temperature more energy is being inputted into the system through the system boundary.


Key point being that there is a point where the intake temp (regardless of the mass flow) would become a problem.

 

I would imagine that proper fuel injector operation would have more to do with adequate atomization than a 20 degree difference in ambient air temp.

CRH

 

Ok-- all in all --after much wait and 2 birthdays (not complaining here)--how close is this package to marketing? General price range? will it be a 5K package--7K package--know you cant commit to a price--and that you have all along been concerned about the cost , marketed with differant pulleys for individuals preferref boost?, include new heat range of sparkplugs in package etc.
I have to tell the wife if we are buying a family jet ski or I am getting this thing for my car. She may have to up her medication depending on the decision, or I may have to up mine depending on how much she hurts me.
olddragger

 

Approximately at what TPS% will the AFSC have sufficient mass flow in to start to making boost pressure.

 

Ok, lets just not give the impression that we are violating PV=nRT just because we are a bit more efficient which I think some people posting on the thread seem to believe. More pressure means higher temps unless you increase volume or reduce the amount of gas.

Only because colder air tends to hold slightly more moisture. In this case that wouldn't make any sense as there isn't anywhere in the intercooler for the additional mosture to magically appear after the air is cooled back down unless you install a humidifier in your intercooler. Or unless there is a lot of water in the gasoline and then better gasoline is in order.

Honestly though if this is supposed to be a reliable steetable (what's that mean anyway?) application I would think keeping the charge temps as low as you can would be the best bet. To me if anything the renesis seems to run hot already.

Not that I'm trying to argue, I'm just trying to find the best product for what I want to do with the car. I'm just not sure that this solution and pettit's provide enough. Last thing I want to do is go through all the trouble and then be underwelmed. I'm not really all that concerned with cost, if I was I would be driving a stock civic.

 

I'll save you the reading.

Price, Noone will know that until richard has a production unit done. all molding and accessories ( new sway bar, piping etc are finalized ) still need to be ironed out. Right now we have a prototype only, a new intake needs to be done, and the pulley problem needs to be fixed and ECU needs to be decided. Richard would like a flash, but we might have to end up using an interceptor or something else and that will change the price. Right now on the prototype he's using an interceptor.

Once the basics are done then we'll do tweaking. a pulley change and retune would be all that is need to increase boost. Even if richard doesn't support it, it can be done.

As far as a timeline for when it's coming. richard said it'd be close to the end of this year for earliest production... sometime in the last quarter

 

[QUOTE=Umbra] More pressure means higher temps unless you increase volume or reduce the amount of gas.

??????????? You want to explain that one to me.





Honestly though if this is supposed to be a reliable steetable (what's that mean anyway?) application I would think keeping the charge temps as low as you can would be the best bet. To me if anything the renesis seems to run hot already.





Not always true for a street car. Smokey Yunick built that homoginazation engine with super heat in the inlet tract by using the exhaust to heat it. It made more response and higher milage then anything else ever did. The onl mode where he cooled the intake back down to normal was the WOT usage.

The better you can homoginize the fuel the more even the burn. Higher pressure means less boiling of the gasoline. Higher temp mean faster boiling. There's always a trade off. Finding the balance is the goal of every power plant engineer. So what do you want to use the engine for.

If you only drove on the salt flats with WOT then you want the coolest charge you can get. In that case it is practical to cool the charge with a limited total loss medium. Like dry ice or freon. This is unusable on the street.

If you drive in traffic all day you would benifit from the opposite. You have to find a balance. BTW why do you still have the hot water flowing around your throttle body if you're so concerned with intake heat? I know you do, with out looking.

 

At what TP will it make pressure?

At the point where you ask for more power then would be available NA.

 

Who gave the impression that we are violating PV=nRT? It wasn't me. If you were trying to say there was an issue with my post, let me elaborate since it is correct. The example I used assumes 6 psi. Insert a number. Lets say that he intends to boost the engine to 6 psi. You are saying that cooler is better. If we insert an intercooler into the system and change nothing else, there will be a pressure drop. I used the number 1.5 psi. That means that the engine is only receiving 4.5 psi at the same blower speed. Ah but it's cooler air you say. In order to get that pressure drop back, we need to increase the speed of the blower. Now it needs to make 7.5 psi at the outlet to make 6 at the engine. That adds heat back into the system as the blower is working harder. Does this mean that without an intercooler it would make more horsepower than with one with the blower working harder? Not necessarily. The less boost you intend to run, the less important the intercooler becomes until you eventually get to a point where there is no point in using one and it is hurting you. As power increases, the need for an intercooler also increases. The point is that at the boost levels he intends to run, the benefit to having an intercooler is very little if at all. If it adds several hundred dollars to the kit price and you get 5 more horsepower out of it from cooler air, was it worth it? You be the judge of that. Also consider the fact that throttle response will slow down with an intercooler. As was already stated, there comes a point where you need an intercooler. With his intended use, it isn't necessary.

 

well that did not help

the reason I *** is I am looking at the Greddy E management ultimate to control the Computer when the ASFS goes on + there is the option to add supplemental injectors with that system AKA Extra injectors before the compressor and they come on during boost conditions and help cool the incoming air charge and since it is now going through the compressor was and get some extreme A/F mixing going on.

 

Forget the Emanage, we have something a whole bunch better coming your way.

But if you insist, what I said is true. When you put enough throttle in to where the engine reach the point of zero manifold that is where you can go unblown. In fact unblown you don't even get to "zero" it will always have some negative pressure. Say an inch of Hg. So if it says 0 on the gage you are actually making more power then you were NA.

Where in TP does this happen, I don't know. It happens different places at different RPM.

 

Pardon my frankness, but if you are going to use some form of management, and you want to know "what TPS boost comes on" and tuning based on that, I can't help but think things might quickly turn to tears. The fuelling and ignition requirements are not soley TPS based or RPM based. For a NA application, RPM and TPS can be used, but for FI applications manifold pressure and RPM are main drivers.

Richards answer is acutally quite right. Boost comes on when you ask for more than atmospheric - via the throttle.

Cheers,
Hymee.

 

The RX-8 has three injectors, and can handle a very wide range of fueling needs. I think even the people runnin 300 whp are using stock injectors. The three injectors are also staged, which means that at certain load and rpm levels, the next injector will start to take over the previous one. The larger injectors are farther out, which will help cool the intake charge, just like you said.

I'm not positive, but I am thinking that using an injector before the AFSC won't be possible. It's not like a postive displacement SC, and (I think) would be more like a centrifugal or turbo in that regard.

 

It's just been exactly 50 years now that axial flow supercharging has used fuel through it with great results. (see June '56 Hot Rod magazine for first test of Latham Axial Flow supercharger) All the Lathams that I built up until 1989 were with carbs before the blower.
There is also a case to be made for injecting the EFI before the blower. See my paper on Holley EFI and homoginization somewhere around page 5 of this thread.
This was a test with both port injection and before the blower compared.

Turbos and centrifugal are the same compressors. They don't do well with fuel in them because they centrifuge it out of mixture, making it worse.
Roots don't do well but are acceptable for some crude applications like drag racing. And hot rods.

Read the aforementioned paper and report back.

Page 3 post 33. wait I'll try and bring in the shortcut trick.
https://www.rx8club.com/attachment.p...chmentid=19452
Read the whole post also. Read post 34, 36, 37, 38 and their attachments. This will answer your gas law questions.

 

Try 6 injectors.