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Renny a weak engine???

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Old 09-12-2007, 11:34 AM
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Renny a weak engine???

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?
Old 09-12-2007, 11:36 AM
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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.
Old 09-12-2007, 11:40 AM
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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.
Old 09-12-2007, 11:45 AM
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the Renisis has NO problems handling boost as long as it's tuned properly. It is NOT weaker then the rest.
Old 09-12-2007, 12:13 PM
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Seven days without hearing one's Renesis makes one weak.
Old 09-12-2007, 12:50 PM
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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
Old 09-12-2007, 12:57 PM
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How many times does this question have to be asked?
Old 09-12-2007, 01:04 PM
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Originally Posted by mysql101
Also, comparing a 2 rotor engine to a 20B is stupid when asking why one makes more power than the other


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??

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

Last edited by Rocketman1976; 09-12-2007 at 01:07 PM.
Old 09-12-2007, 01:07 PM
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Originally Posted by Rocketman1976


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??

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
Old 09-12-2007, 01:10 PM
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Originally Posted by mac11
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?

Last edited by Rocketman1976; 09-12-2007 at 01:32 PM.
Old 09-12-2007, 02:39 PM
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Originally Posted by mysql101
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.
Old 09-12-2007, 02:44 PM
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Originally Posted by Forced__Induction
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.
Old 09-12-2007, 03:01 PM
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Before calling the renesis a weak engine, you should research the difference between whp and bhp...

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"
Old 09-12-2007, 03:08 PM
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Originally Posted by CnnmnSchnpps
Before calling the renesis a weak engine, you should research the difference between whp and bhp...

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.
Old 09-12-2007, 03:21 PM
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Originally Posted by Forced__Induction
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.
Old 09-12-2007, 03:34 PM
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Originally Posted by CnnmnSchnpps
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.
Old 09-12-2007, 06:05 PM
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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.
Old 09-12-2007, 06:25 PM
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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.

Last edited by Rocketman1976; 09-12-2007 at 06:37 PM.
Old 09-12-2007, 07:24 PM
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Originally Posted by CnnmnSchnpps
Before calling the renesis a weak engine, you should research the difference between whp and bhp...

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).

Last edited by sosonic; 09-12-2007 at 07:34 PM.
Old 09-12-2007, 08:28 PM
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Originally Posted by sosonic
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.
Old 09-12-2007, 09:37 PM
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no biggie, if you nearby, I'll street tune your Int-X for a reasonable fee ;-)
Old 09-13-2007, 12:16 AM
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Originally Posted by Rocketman1976
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.
Old 09-13-2007, 11:19 AM
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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.
Old 09-14-2007, 01:51 AM
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kind of sad that what has to be done what way?
Old 09-14-2007, 09:27 AM
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Originally Posted by Forced__Induction
kind of sad that what has to be done what way?
the fixes were done by the users not the company.


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