We're talking about a turbo that capability currently exceeds what we can do with the engine. So I wouldn't call 380-400 whp medium on a renesis.

Size the tool proper for the job, right?

Positive displacement superchargers are OK if you don't mind how inefficient it is or how hot the charged air will be at 9,000 rpm.

 

I have yet to see publicly 380-400whp on your setup...would love to see it, though. The upgrade over the GReddy where you're at now must be really nice, to say the least.

That's a little subjective. Won't disagree that pd SCs are more inefficient, the compressor maps prove as much. But if I were looking for 280whp like the original poster, a pd SC can get you there just like a turbo. Yeah, less torque but whoever only wants 280whp wasn't looking for absolute power anyway. Now if the desire was 380-400whp, like what you listed above, turbo is the only proven method for the engine at this point, and absolutely the most efficient way to get there. Bottom line, I see a place and range of usage for both not so much an absolute.

 

Big Fart Noise

 

I don't have those numbers. That's the numbers of what the GT3071R is capable of. So when you said it was a medium sized turbo, I simply wanted to illustrate that it can do more than we've seen on the car so far. I plan to get to 350 whp and leave it at that. The car is getting close to being "Fast enough" now



The rotary engine was supposed to be a pd sc, so I'm not dissing them

I simply think that the SC's give you less bang for the buck and that turbos have a bad reputation for being laggy when that's not the case unless you install a giant turbo for no apparent reason.

If you like SC's, go for it. But if you tell me it makes more power down low, or up high, or whatever, I have not yet seen any evidence of that for the RX-8.

 

For 280 whp, I say go for a Greddy kit with all the necessary updates. If you still want more when you get there then upgrade it to the MM GT3071 Turbo.

 

Don't think you'll ever catch me claiming that one.

 

To me, the one area where an SC has an advantage over a turbo is the fact that if you size the pulleys properly, you have no chance of overboosting on a SC.

As far as the originally poster's question: the only way I see getting 280whp NA on a streetable engine is by going to a 3-rotor engine. I recently saw in an article where Racing Beat had a high power NA engine that I think was a 2-rotor, but it was for racing only. Plus all the ports were peripherial, so it wasn't a renesis.

 

Trip: unfortunately it's impossible to get 280 without Forced Induction. Trust me, I'm trying to see how much I can squeeze out of my N/A 8 and it's not pretty.

I dyno'd at 191 hp with RB intake + exhaust. Since then I've added the mazmart water pump and high flow cat. I doubt I'm at 200 with those... (no knock on those parts, they're top notch items, just tough to squeeze hp out of the Renesis without FI)
Car definitely sounds great though.

 

well I was at 220 rwhp on a Mustang dyno, that would potentially be very close to that figure at the flywheel

EDIT: ok, he said 280 rwhp NA --->

 

I LoL'd because people ask this question every day... I mean every day

 

Despite, in itself for an OEM 13B that's DAMN impressive! Blows every other OEM 13B out of the water.

 

better add a 3rd rotor ...

 

I guess all of the turbo lag fear got to my head.

Do you think you would be able to tell the difference between getting on the gas in a supercharged RX-8 as compared to one with a GT3071R?

The turbo muffles the sound a good bit, right? Can you/Do you run a catless exhaust after the turbo?

 

We have dynos of the Pettit at 8 psi, so the closest dyno I have is mine at 9 psi - so slightly more pressure, but the difference is approx 50 rwtq on the 3071R over the Pettit for most of the RPM range. I would say the difference would be noticeable.


A turbo is like adding 2/3rds of the muffling sound of a cat. So it's quieter, but not quite stock. If you ran a cat and a turbo, it would be really quiet. Check my videos in my sig.

 

Depends on where you live.

 

no cat + turbo will sound virtually stock. I ran this way for several months. It was cool to hit the gas and go ZOOMING away but the car not make much sound. But I decided I wanted a bit more sound.

 

do you only use the stock ecu and cobb AP for tuning? or do you need some kind of MAP sensor setup?

 

AP works by itself.

If your car is stock, you plug the AP into the odb2 connector and upload the new flash to the car's computer. You're done.

If your car is turbocharged, you unplug whatever you were using before, then plug the AP into the odb2 connector and upload the new flash to the car's computer. You're done.

The only thing you should consider changing is your intake. I don't think the foam filter + maf housing that the greddy kit ships with is ideal.

 

Hey guys this may be a real dumb question so please don't cut me down I'm a newbie to FI. Wouldn't technically a supercharger kit put strain on the renesis since it has to have an extra peripherial running off the eccentric shaft, since you have added another pulley to the belt setup.

 

Strain? not really.. Draw? yes, it is parasitic. You're obviously getting more power back in return than you've leeched off the system though.

This is the same with all superchargers.

 

Pettit's system probably draws around 35hp @ 8psi, as I recall from the compressor maps.

 

Actually the Mazmart Pump is so much more efficient than Mazda's stamp and bend paddlewheel that I believe it made 4 more horsepower on the engine dyno. So you only need 5 from the high flow!

 

For all the talk of how much power the Pettit CAN make it's interesting to note we haven't seen a consumer dyno of over 260-rwhp. And there are a few that have dyno'ed with the Pettit LOWER than stock (not mentioning any names...)

 

If you do almost everything possible with NA than it appears the best you can do would be around 210WHP more or less.

To get 280WHP, then you have to go FI.

SuperCharger vs Turbo, is a plus versus minus scenario. Don't buy into the propaganda from either side or bias that some people have that distorts facts or hides all this issues with a setup.

Evaluate and choose the solution that is best for you.

 

Yep, best to do your own research and evaluate your goals. That way if you pick incorrectly, you can only blame yourself

I had considered SC for a while, but it became apparent after a while that it wasn't the right choice for me.