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Old 10-28-2004, 01:18 AM
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supercharger

Hey guys, I don't think you'd know me but I'm a super mod over on protegeclub.com and I'm currently finishing the first ever mass produced supercharger for the 2.0L protege. I also have a best friend who just bought an 8 and wants me to look into supercharging it. I decided to look around and came across this thread after he mentioned it to me. Here's my thoughts:

1. Centrifugal superchargers don't ALWAYS make peaky power. A vortech, Paxton, etc will make peaky power due to their design but a Procharger, Powerdyne, etc will make huge low-end power. It has to do with the internal gearing of the blower. I know for a fact my Powerdyne BD-600 has an internal step-up of 3.05:1. For every one rotation of the blower pulley you've spun the impellor 3.05 times. That may not sound like much but when you use the same compressor wheel of a T04E .84ar trim it makes aHUGE difference!! Don't count this kit out just because it uses a centrfugal blower.

2. No excess intake temps!! I can't stress this enough. Roots blowers, twin screw blowers, positive displacement pumps add a TON of heat to the intake charge. This usually requires intercooling or water injection. In my kit I don't think combustion chamber temps will ever be a problem even at maz boost but if it is I plan on using water injection to control detonation. I suggest you guys do the same WAY before buying an FMIC. Water injection is much cheaper and much more effective (5X's more effective) than a standard air-to-air intercooler. If you MUST use a roots blower on your car back it up with an auxillary water injection kit. The heat those things put out is going to cost you a motor!

3. There is not a lot of room in the engine bay but with some simple relocation you could have plenty of room to mount a blower, intake plumbing, charge piping, water injection and a custom crank drive pulley. All this can be done while still maintaing your strut bar and stock hood. I saw the pics of the pettit blower and it looked like there were some clearance issues. I'm going to spend some more time this weekend under the hood of the 8 to see what I can come up with but I'm about 90% we're going to relocate his battery to the trunk to see just how much free space can be saved with a $50 mod.


p.s. not to toot my own horn but within a matter of weeks I'll have the only supercharged Protege5 in the world and the only daily-driven supercharged Protege in North America.
Old 10-28-2004, 01:23 AM
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I disagree with you about so many things you said that I don't even know where to start. Thanks for wanting to boost the RX-8 performance though.
Old 10-28-2004, 01:30 AM
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what exactly do you disagree with? That twinscrew blowers produce more heat than centrifugal (namely powerdyne and procharger)?? That water injection isn't more efficent than air-to-air intercooling?? I have no problems sharing with you where I'm getting my info.

p.s. Please vote Kerry '04! thanks.
Old 10-28-2004, 01:39 AM
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Another thing I HIGHLY disagree with. Kerry has his head up Edward's *** for the warmth you know.

Vote Bush or Die.
Old 10-28-2004, 01:42 AM
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so you're not going to back up your argument with fact? You're going to resort to presidential bashing? Typical republican, distracting the populous from the issue at hand.
Old 10-28-2004, 01:58 AM
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Turbo Matty P,

Just curious where you got your ATI Procharger information as the last time Sport Compact Car dynoed the ATI procharger (on a 350Z) the hp/tq curve looked nearly identical to the Vortech unit, and the cars essentially accelerated to the same times. The Vortech unit uses an air to water "aftercooler," while the ATI uses a 3 core air to air intercooler. I haven't seen to many import cars using the Powerdyne system, mostly Mustangs around here.
Old 10-28-2004, 02:15 AM
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I specifically contacted ATI myself when I was sourcing blowers for my kit. I spoke in great detail with ATI about their units. Price was really the only reason I abandoned their product. They make a great blower but when a head unit costs $2100 (jobber cost) I decided I would look elsewhere. I settled on the powerdyne due to it's internaly step-up (i believe is higher than the ATI's), lack of internal oiling, lack of routine maintaince, cost, etc..

Even in the ATI kits they recommend intercooling due to the added heat (no matter how slight). This typically causes lag-type boost on low boost kits. I'm not a fan of air-to-water cooling unless you're capable of running ice water every few minutes. Air-to-air cooling is plenty efficient for daily driven street cars.

I can't speak about the power curves of the 350Z kits because I haven't looked at them. What I have seen is the power curves of almost every powerdyne kit (very similar to ATI's procharger). The curve is basically a nominal increase across the entire powerband. Sure it doesn't make as much power at 3K rpms as it does at 7k rpms but it's still making power and more importantly...torque. I think what you'll feel will be much more like having a larger displacement motor under the hood as opposed to the jet-liner pull of a turbo.

No'one ever expects a supercharger to compete with a turbo when it comes to peak power levels but no'one can deny how great they are for daily driven street cars. I've had both. I much rather prefer my supercharged cars (2000 Contour SVT & 2003 Protege5) as daily drivers and my turbo cars as race cars.
Old 10-28-2004, 02:17 AM
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p.s. There are no Powerdyne import kits yet. They were working on a civic kit but hit a snag when it came to ECU tuning. They asked if I woud finish the kit for them and I turned it down to work on a new blower for the Mazda 3 2.3L. I will be designing an all new Scion 1.5L kit for powerdyne after Jan. 05. Powerdyne's sales manager told me his guys dont like the importsd and prefer to blow V8's!! I thought that was pretty funny!
Old 10-28-2004, 02:34 AM
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rotarygod I know your exact feelings. I respect your restraint. This guy is so deep in his and his vendors BS that fly fishing gear couldn't keep us out of it. On the other hand he may just be illinformed and needs an education. However his attitued matches his political leanings and probably is hopeless.

Funny how the same guy falls for a story both technicly and politicly.

So i will have to go with your enlightend direction and go to sleep.

Last edited by Richard Paul; 10-28-2004 at 02:54 AM.
Old 10-28-2004, 02:39 AM
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Not sure what you just said. You said that you are not a fan of water to air IC'ing, but then in the post above you will not be doing air to air, but water injection. Is air to water IC'ing different to water injection to you ? Are you talking about having a front mount air to air & spraying water in front of it ala the EVO ?

Also in describing the various Centrifugal SC'ers, that is how they are described, as almost larger versions of the current engines. For example the HKS Rotrex SC for the 350 Z has +10% hp increase at 3000 rpm, +25% at 4500 RPM, +40% at 6000 RPM (with a slightly better torque curve). You are right that the centrifugal unit provides nominal hp at lower revs. I think the reason why RX8 drivers like the Twin Screw design is that it supplies more than a nominal hp gain at lower RPMs. It might give only 50 whp, but will give about 85% of that from 3000 RPM all the way to 100% at 9000 RPM. This car needs the hp/torque at low RPMs more than say a 350Z or a Mustang that has a flat torque curve.

I agree that turbo kits have lag vs. some of the SC configurations, but usually they produce more high end (& sometimes mid range) hp than SC's. That is what is appealing to many people, that and the fact that is can be boosted through the electronics.
Old 10-28-2004, 02:39 AM
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you guys can make psuedo-bashes on me all you like but neither of you have yet to disprove any of the comments I've made. If my "facts" are so incorrect maybe you should explain where you think I got misled so we could talk about this maturely.

On a side note: I simply asked (in a VERY polite manner) for you to vote for Kerry. I did not bash anyone on insinuate anything about anyone's homelife or upbringing. If you'd like to start some mudslinging I can surely accomodate you but I prefer to keep threads like this civil and informational. Maybe you should take a lesson from me.
Old 10-28-2004, 02:40 AM
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Originally Posted by Turbo Matty P
so you're not going to back up your argument with fact? You're going to resort to presidential bashing? Typical republican, distracting the populous from the issue at hand.
When you stated Vote for Kerry, you were political bashing as far as I'm concerned.

I'd get into such a long argument on the best types of supercharging and why certain types work better than others and how numbers don't always tell you the whole story and of how water injection is only good as a supplemental system rather than a primary system and how it is only really applicable for street use and how it will run out of water while you are under boost when you need ti the most, and a whole list of other things. I don't feel like arguing about all of those things right now. If I did, you wouldn't ever agree anyways so I'll just let you do what you do and I'll criticize what I criticize. It's far more fun that way.

Vote Bush or Die! That's going to go next to my avatar now.
Old 10-28-2004, 02:42 AM
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I actually meant everything originally in good humor. Your response changed my attitude.

I'm going to let Richard argue facts with you. Look him up on here and see what his credibilities are. You're in for a shock.
Old 10-28-2004, 02:49 AM
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Originally Posted by Fanman
Not sure what you just said. You said that you are not a fan of water to air IC'ing, but then in the post above you will not be doing air to air, but water injection. Is air to water IC'ing different to water injection to you ? Are you talking about having a front mount air to air & spraying water in front of it ala the EVO ?

Also in describing the various Centrifugal SC'ers, that is how they are described, as almost larger versions of the current engines. For example the HKS Rotrex SC for the 350 Z has +10% hp increase at 3000 rpm, +25% at 4500 RPM, +40% at 6000 RPM (with a slightly better torque curve). You are right that the centrifugal unit provides nominal hp at lower revs. I think the reason why RX8 drivers like the Twin Screw design is that it supplies more than a nominal hp gain at lower RPMs. It might give only 50 whp, but will give about 85% of that from 3000 RPM all the way to 100% at 9000 RPM. This car needs the hp/torque at low RPMs more than say a 350Z or a Mustang that has a flat torque curve.

I agree that turbo kits have lag vs. some of the SC configurations, but usually they produce more high end (& sometimes mid range) hp than SC's. That is what is appealing to many people, that and the fact that is can be boosted through the electronics.
Thank you for your civil and mature response to this thread. Apparently it's a lot to ask for here....

Water injection is the spraying of a fine mist of water into your intake tract to help lower combustion temps and prevent pre-ignition. I'm not real knowledgable on rotary engines but on a piston engine water injection on FI motors is a HUGE improvement. It's, very simply stated, a way to help dissipate more heat from the combustion chamber. When water evaporates it removes 5X's the heat that gasoline does when it evaporates. The way boosted motors work is that when boost increases fuel is dumped in the combuston chamber to help remove the heat added by the charge air. Excess fuel (outside of optimal AFR's) is dumped in to help remove the heat. With a small mist of water that excess fuel is not needed and you're allowed to tune your motr leaner for more power even under boost.

That is a very simple explanition of how water injection works. If you'd like more info check out Aqua Mist I believe their website is www.aquamist.uk . Their kits retail for $300-400.


I understand why a wenkel engine would benefit from the boost pattern of a roots blower but I would assume that the added heat to the intake charge would almost make it not worthwhile. If I understand the rotary engines correctly heat is the biggest problem with blowing motors. Also, when used in racing the high rpm limits of the 1.3L would benefit more from a centrifugal blower since it would spend 90% of it's time high in the powerband. I know why a roots blower is more usefull for low rpms but isn't most of your 'spirited driving" done above 4K rpms??
Old 10-28-2004, 02:57 AM
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Originally Posted by rotarygod
When you stated Vote for Kerry, you were political bashing as far as I'm concerned.

.


then you sir are an idiot. If you can't differentiate between a polite request and bashing you have no business reading.

Yes, you can run out of water while under boost with a water injection system. I've used a 1 gallon container in my car and after 3 days of hard driving it was a little less than half full. This included about 20 passes on the 1/8th mile track. If you can't stop and check your fluid level once every 2-3 days then you have bigger problems.

I just addressed the differences between the two types of blowers. I think if you read my post it'll make more sense as to why I don't think the centrifugal blowers are a bad idea.

I'm not "stuck up my suppliers butt". I did my homework and chose the company I thought had the best product. I don't see where you get these baseless accusations from. They are just lame and don't prove anything.

I came on here to share info and learn new things. If you have something to share that is on topic and fact-based I'd love to hear it. If the only thing you can do is throw jabs at me for my political choice then maybe YOU should leave the thread to people who are interested in growing it.
Old 10-28-2004, 03:13 AM
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You know what? I was a little harsh on this guy, I'm sorry he seems calm and did not inflame the thing. So I edited out a little (very little). I still need to react to your kerry comment.

As to Rg's idea of me carrying the ball on this, I only type with one finger. This is a major chore. Matty, IMHO I think you are just starting out in this field and should try and do some book work. First some basic mech engineering would be a big help. Don't go thinking that hot rod DIY type books are correct. They usually are not. They were written by english majors. Not to knock that but they get information from lots of sorces and try to lay it out in print.

You will find reliable information in university level texts. Not bedtime reading but much more reliable. Then read Ricardo and Taylor. Most important Ricardo. He laid out all the rules and backs it up with lab work done on a government scale.

Sorry I can't give a short lesson on supercharging but it is a large body of info and like rotarygod said I 'd never convince you.

Notice my signature about "being written".
Old 10-28-2004, 03:31 AM
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Originally Posted by Richard Paul
You will find reliable information in university level texts. Not bedtime reading but much more reliable. Then read Ricardo and Taylor. Most important Ricardo. He laid out all the rules and backs it up with lab work done on a government scale.
.

I understand what you're getting at. I also understand basic physics and how they are applied in an automotive setting. I'm not calling myself an expert but i'm not an idiot either. I have built many custom forced induction systems and learned many lessons along the way. I've also read a few books, Maximum Boost and Supercharged for 2. Corky Bell is considered an expert in the field and while his books do tend to talk down to a more common level he does address almost every aspect of boosting.

I'm sure when building a LeMans car I'd need much more accurate measurements and clearances and what not. For street cars though the "ghetto-blower" route that everyone seems to be taking works pretty well. Remember, I'm not out to take the world by storm but if I can safely add 50-80whp across the rev range with a powerdyne and water injection I don't see why I should be looked down upon. In all honesty there is not a whole lot of difference in the way I'm designing my supercharger kits and the way any other shop like Sunflower mazda is doing theirs. I've worked in a custom shop before and I bet I'm doing exactly the same type of work on my supercharger kit that Sunflower is having done. It's all pretty much done the same way with the exception of tuners such as Racing Beat, SVT, etc....they have much more access to materials and equipment!!

Do my earlier points about the centrifugal blower being better for the rx8's powerband not hold true? Isn't most "spirited driving" in the 8 done above 4K rpms?? Isn't that about where a roots blower would start huffing straight heat into the motor?? Tell me what I'm missing. I'm quoting general supercharger theory.
Old 10-28-2004, 02:24 PM
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Typical Democrat, stumping for votes in the wrong forum.

jds

Originally Posted by Turbo Matty P
so you're not going to back up your argument with fact? You're going to resort to presidential bashing? Typical republican, distracting the populous from the issue at hand.
Old 10-28-2004, 02:47 PM
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Turbo Matty P, I see you and rotarygod have had somewhat of an altercation. All politics aside, rotarygod is one of the most informed members on this board, and always backs up his info with very, very long write-ups(all factual to my knowledge) and not too long ago he wrote a thread about different kinds of superchargers and each designs advantages. From what I remember they were pretty different than what you've been claiming. Now I've seen tons of dynos of twin screw s/c systems, centrifugal, and roots blowers, and the twin screw is the most efficient. I have never seen a dyno for the axial though but have heard many times about the way the curve works. To my understanding, with a twin screw you get full boost all the way through the rpm range. The centrifugal is exponential(wrong word maybe?) and increases with rpms which is really most suited for the racing world. I'm not going to knock your success, because if you get it to work like you have before, the more power to you. I'm just trying to ease the tension in here and let you know RG is not some random idiot(at least most of the time), but he is very knowledgable about these types of things. PM him or read his threads, I'm sure he'll be glad to answer, and he is pretty civil too, one of the nicer guys on here. He won't simply ignore you because of a petty little argument. I believe it's best to have constructive criticism especially when you're building something so expensive. Get lots of other peoples input. Sorry about the long write-up. Later.
Old 10-28-2004, 03:11 PM
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i agree , i was totally turbo and sc illiterate when i came on this forum but thanks to RG and Richard Paul i feel i have a more informed outlook now/ i don't claim to understand all they talk about(who does?) but their info has been very informative, even to somebody like me that readily admits that i dont know squat. So thanks RG and RP
Old 10-28-2004, 03:40 PM
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Matty P seems like a nice guy, so I'm gunna type a little. That kerry thing still bothers me but maybe we can help him. Matty that is, not kerry.

Where do I start? I guess with the fact that I may be a little bias since I make the axial flow supercharger. But I will still tell you the truth as best I can. I have worked with all except the screw. By that I mean I have built engines and run them on the street and raced them with just about every type out there. I am so old that I helped invent cast iron.

I ran my first Paxton when I was 16 on a Studebaker. That was a car for those who do not know of them. Then on a '60 chevy. In fact I hung out with Andy's son Vince (VJ). We terrorized the LA streets. Why we were never killed I do not know.

So I know cent blowers. I even ran the Factory number 4 Hawk in '64. I had the thing set up with two AFB's and a special Paxton. I drove it to school and to bonniville and the lakes. Once I drove right from school to the lake bed uncorked it and ran 150.5 then drove home. Not fast by todays standards but this was a Studebaker engine in a totaly stock body in 1965. the same car with lower gears ran 112 at the drags. Not impressed wit a high 13 et? Well the tires were only 6 inches wide and not to sticky. That's all we had to run with in that class.

So how about roots blowers? Not going to ramble on but just say I ran some big block engines with roots blowers at the drags, Bonniville and on the water.
I built turbos until I figured out there was to much heat and went looking for the Axial Flow.

So let's start with the curves. It doesn't matter which of the centrifugals you choose they all have the same shape curve, expotential. The internal gearing doesn't matter. They just have to make up the difference with the pulleys. In fact I beleive the numbers you quoted for your choice is less yhen the Paxton. Remember they are all knock offs of the Paxton. I'm not saying which one is better, I do not know. Paxton was due for an update many years ago.

So your thoughts on the gearing is null. Now your heat statment are valid. The roots is very poor after about 4 psi. However the cent isn't that great if you compare it to my blower. We will go there later. Let's go to the water injection. What you are doing here is putting the fire out. Yes it bringss down the temp but what makes the piston go down? The heat. People think there is an explosion in there, not true. It is a smooth burn, hopefully.

What they use in the Merlin is water/alcohol. This makes up some of the loss because it burns, but with less BTU's. Still the introduction of this outside liquid is a bandaid. To go into a project planing on using it is not the right way. I think you are reading the press release of the vendor.

The intercooler has it's own drawbacks and it is a topic all by itself. Let's agree that every degree that goes into the engine carries all the way through. Now every part inside has a thermal limit. Weakest point usually is the piston. Working air raises the temp. Intercoolers do not add more air. If X comes out of the blower that's what you get. By mass. The temp goes down the pressure goes down and vs/vs. The mass is the same. It is just that iff it is hot you can't use it because something fails.

There are trade offs for everything. It takes pressure to push air through the cooler. It adds plenum volume. It adds bulk, weight and cost. It gets in the way of everything. Idealy you would design around it. Also how well it works depends on the delta of the temps. So you don't get all that much if you are running street type pressures. Then there is what speed are you going. This is the airflow.

So two of you componants are really bandaids for a poor design. Well that is a little harsh, lets say an ideal design would not need them. Same for spraying the intercooler. All these things were developed for a reason and have there place. I'm not trying to knock them. I just don't see starting out designing them into the system from the start on a street engine.

OK turbos are different, there you are going to have heat up the ying yang. So intercoolers are always in the picture. That's my main problem with them. That and pluging up the exhaust. Yet I still would like a Bentley Continental.

What do we know? Roots run at 50% or less
Cents run about 65% Axial Flow at 85%. (had to get that in)
The screw runs almost as good as the cents.
I have laid out all the math for this at the begining of my thread (axial flow supercharger) also in there you will find some great plots by "Turbine" that show the difference of efficency output. That will give you an idea of temp from different compressors in actual degrees. Plus you will find the rotary's actual airflow compliments of Hymee.

You will find the formulas for just about everything you need. Now let me tell you that it will still only be a ballpark number. Only the dyno tells the truth. There are just to many factors.

Now why doesn't the cent fit the rotary well? Because it has the same sort of output. Nothing at the bottom. Now my blower splits the difference byhaving a strieght line not a curve. the roots has a flat line. These are all in theory because manufacturing clearances and minor design differences. That assumes each is designed right to start with. You can have a poor design in any one of these.

So there are trade offs for everything. Sadly your choice has to many if you consider the size and bulk of the head units. Add in some intercooling ducts and you have a nighmare of packaging. It can be done for sure, yet it's getting harder all the time.

About the only thing you have going for you is that at some point in the curve the power to drive a roots plus it's heat(there conected) will kill the power coming out the flywheel.

I've gotten myself confused now that I talked to much. I can't even remember all the points I have pouched and not. But I;m too lazy to go back and read it all. Therefore I may have forgotten something but I;m sure someone will ask.

Richard

Last edited by Richard Paul; 10-28-2004 at 04:03 PM.
Old 10-28-2004, 04:16 PM
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I'm sure you have a nice blower coming out. I've heard good things about the axial blowers although nothing technical.

I understand the draw of a blower that builds power down low on the Renesis but this contradicts what spirited driving would demand. I read the reviews of the pettit blower and they mentioned how between shifts rpm's never dropped down belwo 5k rpms'' (guessing there). I think I remember specificaly hearing something about the supercharger only being usefull from a dead stop with no drag launches.

I'm not here to dish on anyone's product by any means. I'm here to learn about what other people are doing to see what works. I'm pointing out what I've learned from my own experience, other peoples testing and what I've read. I'm not trying to be argumenative I'm inquisitive. I need some sort of proof to disprove what I've been taught or learned on my own. I'm more than willing to admit I don't know everything and I'm always up for hearing both sides.

Can someone explain why a blower that makes sub4K rpm power is going to be beneficial to a high revving motor such as the renesis?? Won't you be out of the benefits of a roots blower between shifts?? Once you get that roots blower spinning you're going to start pumping straight heat into the motor. It seems that anything above 5K rpms would be worthless.

I don't know anythign about the axial blowers thats why I havent mentioned them. What does a rotrex.axial blower cost (just the head unit). I'd like to work with one to see what I think. If they are as great as you say I may switch brands. Like I said.l I did my homework and chose who I thought was the best.
Old 10-28-2004, 04:52 PM
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Matty: When I said I disagreed with alot of what you wrote, I didn't mean that I disagreed with everything. Well, I disagree with your politics but there are enough of those threads here and they are all mean. Sorry we got off on a rocky start. I am happy you want to boost the power of the engine but I don't agree with the method that you have chosen. Is a centrifugal fairly efficient? Yup. A twin screw is pretty damn close to it in the efficiency department though. I won't argue about the roots. I don't like them. They are antiquated. Since this is your preferred method, you will probably not agree with me. Will you enhance the performance of the car? Yes. Can you do better? Yes. Here are my concerns. They aren't criticisms so put the hostilities behind you.

If we compare a properly sized twin screw to a properly sized centrifugal supercharger on the same engine and run the exact same amount of boost, the twin screw is going to be faster. At least where it counts it will. If you have a centrifugal (Paxton, Powerdyne, Vortec, or otherwise) setup for 8 psi, that is only at about 8500 rpm in the case of the RX-8. Below this it makes far less. How much boost is it making at 4000 rpm? Maybe 3 psi or so? The twin screw set at 8 psi will overcome any leakage and be at full boost by 4000 rpm or sooner. The twin screw will also hold this up to redline. It's efficiency is very close to a centrifugal supercharger but maybe slightly less. So lets account for this very slight efficiency advantage for the centrifugal. This means that at 8 psi the centrifugal is producing more power. Let's be optomistic and say that the centrifugal needs 7 psi to equal the twin screw at 8 psi. What rpm is the centrifugal at 7 psi? 7500 rpm or more? So this means that up to roughly 7500 rpm or so the twin screw is faster. Above this the centrifugal is faster. I'll bet the horsepower gain isn't much above though. The twin screw can go through the rev range faster than the centrifugal since it makes far more average power. I think I'd rather be faster where my car stay at 99% of the time. If this were a dragster with an auto transmission that was set up to run at a very narrow powerband say 1000 rpm wide, then the centrifugal might be worthwhile. They are not the best choice for power for street use. The twin screw also has much better off idle response. Remember low end boost adds up to low end torque. Torque = fun.

For the fun of it let's compare the axial flow supercharger to the centrifugal. It is a compromise between the boost curve of the centrifugal and the positive displacement. It has a big advantage in efficiency over all others though. Since your centrifugal is geared at 3 to 1, your boost stays fairly low for a while in the rpm range and then starts to take off on the top end. The axial is a nice steady boost. Twice the rpm is twice the boost where for you 3 times the rpm is twice the boost. This translates to a supercharger that still has more low end power than a centrifugal. Now we don't have as much boost as a twin screw down low but we have more efficiency. If our twin screw at 8 psi is making the same amount of power as the axial at 5 psi, it isn't going to take long for the axial to overcome it. The axial will make more power everywhere over the centrifugal and probably more than the twin screw after about 4000 rpm. I can live with that. That is certainly more reasonable than playing near the rev limiter to get the best gain. The axial also makes less heat. At the same boost levels, not only is it making more power, but it has less charge heating. Where you would need intercooling, the axial might not. I'm not saying that it can't help but there are a host of other issues which Richard has already stated that I won't get back into. It's a neat little device.

Water injection does have it's place on cars. Race cars that run the 1/8 or 1/4 mile. It isn't practical on the street or on a road course. Alot of people complain about having to add oil to the car between oil changes since the rotary burns some in the combustion chamber. They aren't going to be receptive to having to add a gallon of water every 3 days so they can keep making power. If you have to refill a tank every few days in order to make power you should use the option called nitrous. Same inconvenience. Nitrous has the advantage of price though.

I also don't consider water injection to be something that should be relied on like an intercooler. It is a supplement. It is added benefit. If it runs out at full boost, you shouldn't worry since you should need it to run full power. The problem is that so many people tune their cars to the edge and then use water injection to get it a little past it. When they run out of water they detonate. You'll run out at full throttle. That's almost as bad as hitting fuel cutoff at redline under full boost. Bad news. It's use should be to enhance the intercooler rather than replace it. Since you are fond of Corky Bell (Richard knows him personally btw!), Corky writes that water injection should be avoided. He was actually pretty vague about it though. He isn't against it. He is against using it instead of intercooling. He doesn't like it when people rely on it. He has no problems with it being used as a supplement. As I understand it, you want to use water injection instead of an intercooler. I will stronly have to disagree with this except for drag use only.

A centrifugal supercharger is probably the easiest to integrate onto the car. You don't have to change anything else. You just add to it. A twin screw would require all new intake manifolds. From a simplicity standpoint I can see why you want to do it. From a performance aspect I can't. Water injection is also much easier than integrating an intercooler. Again from a simplicity standpoint I can see why you want to do it. From a performance aspect I can't. You have coincidentally chose the easiest way to integrate a supercharger into the car. It requires the least amount of effort and fabrication. Don't get me wrong, I'm not saying it is easy. I'd just rather see more performance enhancements where the car needs it. That is in the low to midrange and not only the top end.
Old 10-28-2004, 05:14 PM
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good info and much better than your previous post of "everything you say is wrong".

You misunderstood what I meant about water injection. If you go back and read my post I mentioned that the particular blower I was using on my protege kit will not be intercooled. The reason why is that it will not add the same amount of heat to the intake charge as other blowers do. Also, intercooling on a low boost supercharger can cause severe driveability issues such as lag, stumbling and hesitation. My kit should make between 6-8psi and produce right at 200whp with no intercooling or water injection. What I said earlier was that SHOULD I max out my blower at 12psi I would prefer to add water injection over intercooling. I have already made a FMIC for my car and it was part of my initial plan when I was working on a procharger kit. I have no problems making FMIC's or customizing anything for that matter. You seen to want to say that I'm taking the easy route on everything. I resent that. I'm more than capable of doing anything required of me other than creating my own cast manifolds out of aluminum.

On another note If you want to compare efficiency between eaton blowers and centrifugal blowers I have a few numbers for you:

Saturn Ion Redline--2.0L 4cyl Eaton M62 @ 14psi = 200bhp or 179whp

Mazda Protege5--2.0L 4cyl Powerdyne BD-600 @ 6psi = 180-200whp

again my numbers are not proven yet but they will be within a few more weeks. I just wanted to point out that it requires more than double the boost level of the eaton to keep up with a centrifugal blower. Both cars redline at the same 6500rpm. Also, the Eaton blower on the Ion IS intercooled...mine is not.
I don't know anythign about the axial blowers so I can't even begin to speculate about how it would stack up.
Old 10-28-2004, 05:24 PM
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Originally Posted by Turbo Matty P
good info and much better than your previous post of "everything you say is wrong".

You misunderstood what I meant about water injection. If you go back and read my post I mentioned that the particular blower I was using on my protege kit will not be intercooled. The reason why is that it will not add the same amount of heat to the intake charge as other blowers do. Also, intercooling on a low boost supercharger can cause severe driveability issues such as lag, stumbling and hesitation. My kit should make between 6-8psi and produce right at 200whp with no intercooling or water injection. What I said earlier was that SHOULD I max out my blower at 12psi I would prefer to add water injection over intercooling. I have already made a FMIC for my car and it was part of my initial plan when I was working on a procharger kit. I have no problems making FMIC's or customizing anything for that matter. You seen to want to say that I'm taking the easy route on everything. I resent that. I'm more than capable of doing anything required of me other than creating my own cast manifolds out of aluminum.

On another note If you want to compare efficiency between eaton blowers and centrifugal blowers I have a few numbers for you:

Saturn Ion Redline--2.0L 4cyl Eaton M62 @ 14psi = 200bhp or 179whp

Mazda Protege5--2.0L 4cyl Powerdyne BD-600 @ 6psi = 180-200whp

again my numbers are not proven yet but they will be within a few more weeks. I just wanted to point out that it requires more than double the boost level of the eaton to keep up with a centrifugal blower. Both cars redline at the same 6500rpm. Also, the Eaton blower on the Ion IS intercooled...mine is not.
I don't know anythign about the axial blowers so I can't even begin to speculate about how it would stack up.

The big question is where does your car make that power? Right near the redline? I'd also like to add that I have seen dynos of that redline ion with the whp about the claimed 205. I think i saw a dyno showing about 211 or so? Either way, dynos don't really mean anything, if your peak hp is at or right near the redline, but the rest of the powerband is really lacking, then it's just not worth it. The car with the best average horsepower will win every race. (Stolen from RotaryGod)

Last edited by Aoshi Shinomori; 10-28-2004 at 05:55 PM.


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