I am having a hard time understanding this. There are alot of people getting huge HP out of the 20B, and the 13BREW, but why not the renesis? why is this engin so much weaker than all the rest?

You can boost both of those engines up above 20+ PSI if you desire.

Look at the power that both of those motors make, naturally aspirated, unported compared to the renesis. The renesis makes more hp/L than either so when the time comes that you can put as much boost through the renesis you will see a lot of power.

Higher static compression, PCM issues, Lack of time for R&D (newer car). Lack of motivation to blow engines..... fuel system, IGNITION system is a big one, etc...


Take your pick.

the Renisis has NO problems handling boost as long as it's tuned properly. It is NOT weaker then the rest.

Seven days without hearing one's Renesis makes one weak.

It's similar to the rest, but you have to keep in mind it's newer, the ignition system is currently what's holding us back, and the fact that it has higher compression rotors. Those things aside, the renesis is as strong, if not stronger than the previous engines.

Also, comparing a 2 rotor engine to a 20B is stupid when asking why one makes more power than the other :)

:banghead: :spank: :cussing: :boxing_sm :bottom: :greenchai :Kill2: :pfanndina :tank: :ar: :ak47: :whipping: :rl: :bash: :dark: :dienewbie

How many times does this question have to be asked?

Also, comparing a 2 rotor engine to a 20B is stupid when asking why one makes more power than the other :) :lol2: :lol2:

To add to the above 20b is same motor just bigger version, thats like taking a Dodge hemi v8 and asking why the Vipers v10 is more powerfull??:rolleyes:

It's just newer and give it time once (like stated a few posts above) time for R & D has gone by and ignition systems are developed we will be making 400-500 rwhp with the Reny

:lol2: :lol2:

To add to the above 20b is same motor just bigger version, thats like taking a Dodge hemi v8 and asking why the Vipers v10 is more powerfull??:rolleyes:

It's just newer and give it time once (like stated a few posts above) time for R & D has gone by and ignition systems are developed we will be making 400-500 rwhp with the Reny

only the v10 in the viper is not based on a "hemi" architecture

only the v10 in the viper is not based on a "hemi" architecture

I know its been around longer than the new hemi and the v10 isn't hemispherical combustion chambers. Just saying N/A v10 vs N/A v8 why faster? Not a good question.

Why you gotta get all specific on me?

It's similar to the rest, but you have to keep in mind it's newer, the ignition system is currently what's holding us back, and the fact that it has higher compression rotors. Those things aside, the renesis is as strong, if not stronger than the previous engines.

Also, comparing a 2 rotor engine to a 20B is stupid when asking why one makes more power than the other :)

Im not asking why the 20b makes more power, im referring to what it can handle as far as boost and tuning. I am aware that the renesis is a great improvement over the 13rew. it makes just about as much power as the rx7, only NA. im just trying to find something reliable. (turbo, s/c) it seems like there are alot of people having problems, and the improvements arent even that good. 280hp over 235 stock doesnt seem worth the money to me. Maybe im wrong though.

Iim just trying to find something reliable. (turbo, s/c) it seems like there are alot of people having problems, and the improvements arent even that good. 280hp over 235 stock doesnt seem worth the money to me. Maybe im wrong though.

You are wrong. For $3,000, you can go from the stock 170-190 up to 270-290. So roughly 100 whp increase.

Stock gets about 140 tq, you'll be in the 220 tq range with the greddy.

Before calling the renesis a weak engine, you should research the difference between whp and bhp... :lol2:

Most peoples' problems are due to low quality installs, pre-existing conditions exacerbated by the additional load, or bad tuning...

mysql: there's no way you can get a a full system for $3k ;-) An install with that kind of budget will end up as another example of "the weak renesis"

Before calling the renesis a weak engine, you should research the difference between whp and bhp... :lol2:

Most peoples' problems are due to low quality installs, pre-existing conditions exacerbated by the additional load, or bad tuning...

mysql: there's no way you can get a a full system for $3k ;-) An install with that kind of budget will end up as another example of "the weak renesis"

Installing a turbo for this application is basically bolt on at this point. There are no head gaskets to add to lower compression or anything like that. The most challenging thing is tapping the oil pan for the oil return line.

Now tuning is something entirely different.

Im not asking why the 20b makes more power, im referring to what it can handle as far as boost and tuning. I am aware that the renesis is a great improvement over the 13rew. it makes just about as much power as the rx7, only NA. im just trying to find something reliable. (turbo, s/c) it seems like there are alot of people having problems, and the improvements arent even that good. 280hp over 235 stock doesnt seem worth the money to me. Maybe im wrong though.

No turbo on here gives only 30-40 horse your comparing two different measurements.

I guess you don't understand the diff between Rear wheel horse power and rated horse power at the flywheel. You lose between 12-18% hp from your motor through the transmission and to the back wheels. the 238 is rated at the motor, at the rear wheels the car puts down 170-180 hp, the Greddy kit makes you have 260-290 hp at the rear wheels, this number when you add the transmission loss equals 320+ hp at the flywheel, stock 238 flywheel, greddy 320+ flywheel and as he said above torque is 135 at the wheels stock and 210+ with greddy at the wheels which = stock 159 flywheel torque and greddy 250 flywheel.

By the way, with the fuel map in stock setup your RX-8 makes more like 210-220 flywheel horse power. After a good tune or and full exhaust you get 238 horse.

mysql: there's no way you can get a a full system for $3k ;-) An install with that kind of budget will end up as another example of "the weak renesis"

Maybe not new, but a used greddy will go for around $2,000, complete with BOV and boost controller. So pay another $1,000 for the install and you're set.

You don't have to tap the oil pan either. The greddy kit screws into the oil drain hole. So when you do oil changes, you have to unscrew the turbo oil return line - oil pours out, then screw it back in. you can also get the greddy oil pan - there's two drain holes there. So one for the turbo return, and one to actually drain oil.

lower compression --> more boost --> more power.. generally speaking.

even with an ignition upgrade and all supporting mods, 400whp will be a hard mark to hit with rene. single turbo fd can do it quite easily.

don't let the fact that we're close to 400whp now fool you. it won't be an easy achievement with pump gas.

Is it true that the compression ratio of the renny can't really be compared to the compression of a piston engine with the same exact same ratio as the renny? Some one on Rotarytuner.com mentioned that.

Before calling the renesis a weak engine, you should research the difference between whp and bhp... :lol2:

Most peoples' problems are due to low quality installs, pre-existing conditions exacerbated by the additional load, or bad tuning...

mysql: there's no way you can get a a full system for $3k ;-) An install with that kind of budget will end up as another example of "the weak renesis"

Word, I don't know why people keep acting like all you will spend is $3k in the Greddy turbo. Yeah, its the top for HP per dollar right now, but you are going to spend more than $3k. Its just slightly.... ah... unethical to hide other costs. Its better to give people a better picture on cost for a new kit. Tuning, install, EMU, etc... will be factors too... Also, people may want to consider upgrading that turbo with the Mazsport upgrade (though I would like to see a dyno of it).

Word, I don't know why people keep acting like all you will spend is $3k in the Greddy turbo. Yeah, its the top for HP per dollar right now, but you are going to spend more than $3k. Its just slightly.... ah... unethical to hide other costs. Its better to give people a better picture on cost for a new kit. Tuning, install, EMU, etc... will be factors too...

Hardly unethical. Your cost will be based on what you want, and how much work you can do yourself. With a used kit, you can definitely get it 100% with just 3k including install. Add 200-400 if you need some tuning for the fuel management.

If you go new, it's about 3.3k for the kit, 200 for bov, 1k for install, 100 for new hoses, $5 for oil pill, 400 for dyno and street tuning.


Of course, there's a ton of extra crap you can buy, but to get the reported ~100 whp gains, that's a complete list.

no biggie, if you nearby, I'll street tune your Int-X for a reasonable fee ;-)

No turbo on here gives only 30-40 horse your comparing two different measurements.

I guess you don't understand the diff between Rear wheel horse power and rated horse power at the flywheel. You lose between 12-18% hp from your motor through the transmission and to the back wheels. the 238 is rated at the motor, at the rear wheels the car puts down 170-180 hp, the Greddy kit makes you have 260-290 hp at the rear wheels, this number when you add the transmission loss equals 320+ hp at the flywheel, stock 238 flywheel, greddy 320+ flywheel and as he said above torque is 135 at the wheels stock and 210+ with greddy at the wheels which = stock 159 flywheel torque and greddy 250 flywheel.

By the way, with the fuel map in stock setup your RX-8 makes more like 210-220 flywheel horse power. After a good tune or and full exhaust you get 238 horse.

I know the differences between brake HP and wheel HP. i just never really thought about it when looking at the stats. And what about all the problems people seem to be having with the greddy kit, are most of them sorted out?

Another beef i have is with greddy itself. Ive heard quite a few stories posted about greddy not having any customer service whatsoever. all they want you to do is deal with the retailer. what kind of company does that? to me only a poorly run overly-capitalist aftermarket company.

And for the record..................................IM NOT CALLING THE RENESIS A WEAK ENGINE!!!!!!!!!!!!!!!!!!!!! i was asking a question, not making a statement. Ive got mine on a Zex wet nitrous system right now, and its handling it pretty good. Im extremely happt with it.

Its kind of sad that it has to be done this way the pretty much all the issues with the greddy kit have been addressed, its just been by people around here that wanted it to work properly. There is a thread floating around somewhere with "Greddy fixes" or something along those lines.

kind of sad that what has to be done what way?

kind of sad that what has to be done what way?

the fixes were done by the users not the company.

+1 on the problem being the high compression ratio. There are reasons why cars that are FI from the factory have lower compression ratios!

want.........FI

want.........FI

do it.

561-844-2258

727-530-9960

what are these numbers?

petit and mazsport.

I've seen this mentioned before and have to ask how dose the ignition hold the power back. How does the FI cause the current spark to be insufficient?

It's similar to the rest, but you have to keep in mind it's newer, the ignition system is currently what's holding us back, and the fact that it has higher compression rotors. Those things aside, the renesis is as strong, if not stronger than the previous engines.

Also, comparing a 2 rotor engine to a 20B is stupid when asking why one makes more power than the other :)

I've seen this mentioned before and have to ask how dose the ignition hold the power back. How does the FI cause the current spark to be insufficient?

check the dyno comparison thread. You'll notice all the high end kits max out around 330 whp. The stock ignition system can't handle anything higher.

Mazsport appears to have an upgrade solution around the corner. If they post some dyno charts of their kit above 330 whp, their ignition upgrade will become one of the bigger TODO items for anyone FI.

check the dyno comparison thread. You'll notice all the high end kits max out around 330 whp. The stock ignition system can't handle anything higher.

Mazsport appears to have an upgrade solution around the corner. If they post some dyno charts of their kit above 330 whp, their ignition upgrade will become one of the bigger TODO items for anyone FI.

Hey, there's a go-fast advantage to living here in Sunny California after all: with our faux 91 octane (really more like 89), we'll never get past 330 wheel without race gas anyway so no need for the ignition upgrade

Hey, there's a go-fast advantage to living here in Sunny California after all: with our faux 91 octane (really more like 89), we'll never get past 330 wheel without race gas anyway so no need for the ignition upgrade

wow. That's awesome. I'm envious.

Mazsport appears to have an upgrade solution around the corner.

this is another beef i have about these aftermarket companies. every good product for the RX8 seems to be "around the corner". ignition, around the corner. cobb programmer, around the corner. supercharger kits, around the corner for like 2 years (and yes i know its available now). flawless greddy turbo kit, AROUND THE FREAKIN CORNER!!!!! No offense intended to you mysql101.

Another question i have is this. I have heard that all the turbos that are available in kits for the 8 right now cannot provide sufficient airflow to feed the renny at high rpms. this in turn gives plenty of increase over stock in the lower revs, but not much up high. is this true?

this is another beef i have about these aftermarket companies. every good product for the RX8 seems to be "around the corner".

I don't think mazsport has made any such announcement. But we know they're working on it :)



Another question i have is this. I have heard that all the turbos that are available in kits for the 8 right now cannot provide sufficient airflow to feed the renny at high rpms. this in turn gives plenty of increase over stock in the lower revs, but not much up high. is this true?

Not true.

The greddy is the smallest turbo for the RX-8. I think it's the only undersized turbo too. Now, before we jump on greddy's back for supplying us with a small turbo, keep in mind the greddy kit is setup for 6 psi. It does 6 psi all the way to redline too. So it's actually perfectly sized for the application.

What we end up doing is raising the boost. It can't flow enough air to maintain 12 psi at redline, thus the boost decreases....

here's a really nice greddy dyno sheet that shows PSI (on the bottom):

http://www.rx8club.com/attachment.php?attachmentid=107423&d=1189649274

He's making almost 300 whp, and 250 lb-ft of torque. Even when the boost dies down, he's making 270 whp range. Compare that to a stock RX-8 that puts down 180 whp and 140 lb-ft torque. Doesn't sound so bad, does it? :)

no, not that you put it that way. it always kinda pissed me off, thinking that the turbo/sc kits didnt provide much improvement for the money and risk. but i never really thought about it in terms of whp and bhp. i dont know why it didnt hit me before. this is really beginning to sway my decision to wait for the turbo. im looking for a good ecu right now. lotsa people seem to like the e-manage ultimate, i might do some research in that forum. is there any other turbo kits worth taking a look at? im not too keen on a supercharger, but is there a "better" turbo kit out there than the greddyi should be looking at?

Having seen (and heard!) the Pettit SC in person, I would advise you to not discount it out-of-hand. At least watch a vid, but the best is to hear it in person. Incredible!

As far as turbo kits go, it seems that the Greddy is the cheapest, but also the lowest power gain. Mazsport offers some great kits. Check out the thread in the Major HP forum with price comparisons and dyno graphs.

Also, if you are interested primarily in drag racing, nitrous is a good option. Gives you great WOT performance, and doesn't kick in during daily driving. A 55 wet shot does not require an ECU and Zex sells a system for about 600 bucks with almost everything you need. If you want to go down this path search for posts by "Charles R. Hill".

Happy hunting!

mysql, is that dyno posted an rx8 with a greddy kit? 293whp compaired to 325whp. 30whp difference doesnt warrant a doubling in price. if the greddy kit can put down close to 300whp for its cost, that sounds pretty attractive. i thought it did something like 250-260whp.

yeah, that's the greddy. it does do about 240-250 at the stock settings (6 psi). But if you buy a $200-300 boost controller, you can adjust the boost. The graph above is at 10 psi. You should expect somewhere around 270 whp with it.

Some of the kits are pushing very close to 400whp, but yes the law of diminishing returns applies. Also, it seems that some of the kits are still priced as if they're the only thing on the market.

You gotta decide if money or power is more important, then pick a hard number in that category and choose a kit accordingly. Don't forget that there will be hidden costs (labor, extra parts, "extra" things like gauges, etc.)

Also, if you aren't dying to go FI this very instant, things will probably go down in price in the next year or two as the market matures a little. A used kit might also be a good deal.

Also, if you are interested primarily in drag racing, nitrous is a good option. Gives you great WOT performance, and doesn't kick in during daily driving. A 55 wet shot does not require an ECU and Zex sells a system for about 600 bucks with almost everything you need. If you want to go down this path search for posts by "Charles R. Hill".

Happy hunting!

i have the zex wet kit on my 8 right now and i love it. but i want FI BAD!!!!

Right now, the best bang for the buck is the greddy kit. Everything else costs twice as much, and some kits that cost twice as much make even less hp and torque than the greddy.

I would far rather pay twice as much to get a product that is equal in performance if it comes from a company that actually does research and supports their product, not to mention actually wants their customers opinions and suggestions, instead of a bullshit company that doesnt care about any problems that are showing up, and doesnt want to have anything to do with the end user beyond the $$$.


and as far as the labor costs CnnmnSchnpps, i made my mid up a while ago that i wouldnt do anyhting to a vehicle that i cant do myself (with the exception of sterio equipment). I am very proficient with tools and am right at home under a car on jack-stands. the nitrous kit was a breeze to install. it took me a while, (8-10 hrs) but i dont kike to rush things. I would absolutely love the chance to install a turbo kit.

Yeah, installing it yourself is definitely the way to go... Then you know where to start debugging when things start to go wrong. If you want to do the isntall yourself the turbo would be much easier than an S/C since there are no mechanical connections to worry about.

For the rest, you gotta do your own research... There's quite a few kits out there at this point. I read about the Mazsport kits as they were coming out and I was impressed, but there may be newer ones that might be even better... Those threads get pretty long but there's no real substitute to getting direct feedback from owners (instead of the "a guy that I know knows a guy who has a greddy kit and it blew his engine up" type of talk)

Before calling the renesis a weak engine, you should research the difference between whp and bhp... :lol2:

Most peoples' problems are due to low quality installs, pre-existing conditions exacerbated by the additional load, or bad tuning...

mysql: there's no way you can get a a full system for $3k ;-) An install with that kind of budget will end up as another example of "the weak renesis"


I bought my greddy kit for 3k and installed it myself. So I think it is very much possible. And it rean flawlessly.

renesis is still fairly new, calm down.

please. let. this. thread. die.

well, seeing that people are pushing 300+ whp with newer turbo kits with this engine, unported just FI kit, and this car has been out for only 4 years, I think we are significantly better, than the other engines

are we done yet?

I don't know, are we?