First of all, removing the rev limiter is not a good idea. It's there for your safety and that of your vehicle.

The primary issue with power gains on this motor is in it's N/A form there isn't much room to grow. The car isn't de-tuned to the same extent you'd find with other vehicles.

Intakes don't do anything because the whole aspect of aftermarket intakes is to fool the Mass Airflow sensor into leaning out your fuel mixture. The RX8 PCM can trim fuel delivery when the readings are out of whack which means any gains you'd see are negated.

You can remove any restrictions in the exhaust by eliminating the cat, however there's no real conclusive data to show what restrictions, if any, remain with a catless system.

Tuning will yield power gains but how much can vary between cars. Some people see a lot, some not so much.

The process of chasing 10 to 15whp is very expensive with this car. Ask me how I know.

The easiest and most straight foward means of getting more power is either going to be a nitrous setup (which isn't something that works where the RX8 plays) or a turbo setup.

Nitrous is clearly a drag racing item since it requires full throttle and high RPM's to operate within safety zones. If you autocross or road race nitrous isn't allowed.

A turbo would be another option. The greddy kit is the most affordable and there are members here with some worthwhile upgrades that make the kit a better bang for your buck. There are some parts which need upgrading so there is going to be some added cost.

Otherwise, there are other kits out there that will do what you need including supercharger kits which have been used with success.

All things being equal, the RX8 would produce more power by expanding the RPM rev limit. With the reduction in VE, however, the amount of produced power will decline past 8,800 RPM's. About the only benefit of running the gears out is it puts you right back into the strong power band of the car.

You'll spend a lot of money for a modest power increase. It's pretty much all or nothing.

 

Banner, most of the vendors offering tunes are talking about leaning out a bit & adding a few HUNDRED rpms, not a few thousand.

If you are worried about hp gain, a cat back exhaust, and/or high flow cat/test pipe will not get you the added hp that you are looking for. Sorry to burst your bubble. Better off spending the money on a nice nitrous kit.

 

No way I'm putting nitrous kit on this car, to be honest I don't think the engine would hold up to it. (I've run it on other cars before). Plus Nitrous is a serious ticket here in California if they catch you with it. Then there is the added hassle of bottle warmers, openers, and purgers, and if you're not careful you can blow your engine when you start it.

And then it's only good at WOT, so no, not really worth the money or the hassle for that. I think at this point I'm not going to do anything to the car, except maybe buy the cobb. Sort of surprised that there is no simple way (simple as in under a couple grand) to add 20 to 30 hp to the car.

Yeah maybe I should have done more research, but just never had a car before that was so hard to get anymore power out of without spending a fortune. I love the way it handles, I like driving it. So I guess at this point it's either leave it as it is, turbo it, or put a better engine in it. A better engine is probably be the best option, cause the savings in gas alone would pay for it. Course that would screw up the balance.

 

would love to see how you worked that out ....

 

 

While I'm not a resident expert on nitrous, I can say with confidence that the motor can indeed handle it. The motor is capable of handling 14psi of boost so a nitrous shot isn't going to be any problem. The major challanges of the nitrous setups are delivery methods and how to retard your timing without having to switch flashes all the time.

The challanges with the delivery system is that the intake manifold isn't designed to flow fuel, just air. With the amount of fuel being added for anything more than a 55 shot, puddling becomes a problem and the risk of a nitrous backfire grows.

In terms of being caught with it, BHR has managed to put together both parts and installation which leaves the nitrous system almost invisible. Unless the cop started taking stuff apart there wouldn't be an issue.

The WOT aspects are a drawback and limit where you can use the nitrous.

I don't know your mechanical background, but any kind of a motor swap with the RX8 is going to be an expensive and intensive project. People have done it with success but at great expense. If you're looking for a cost effective way to gain power that's certainly not one I would suggest.

The problem with cheap power gains is this car is different from every other piston powered vehicle. You can't build out this motor in the same fashion where you can upgrade pistons, rods, cams etc.

The RX8 has lots of advantages with it and it's a great performance car with about 280 - 300whp. You'd be surprised at what vehicles the car can keep up with when you have that amount of power.

 

I know quite a bit about nitrous, I've run it before (up to a 125hp shot) I've also had to hide it in a car (false bottom trunk, fun that). The power characteristics for nitrous makes it more of a drag car item, (on off, no ramping) and that's not what I'm looking for with this car. Also, it is a lot harder on a car than a turbo.

My Mechanical skills are extensive actually, I've been wrenching on cars since the 70's. And I agree, that this car with 280 to 300 whp would be a complete monster. No doubt about it, the handling is fantastic, the car corners wonderfully. At 120 (as fast as I've taken it so far) it is stable and well planted. The nose doesn't get light and I've not noticed any tendency for it to misbehave.

The problem is of course is that the car comes with 232 Hp (and I doubt that's whp). The best prices I've seen on a greddy kit to date is 4K, which isn't too bad, but then I see a lot of people saying you need to put an additional 2K in because the kit is so poorly made. Also I'm not looking to be at that 280 to 300 mark, and with gas threatening to make 6 bucks a gallon by Labor Day, I don't think I want to drop the MPG any more than the 16 it's at already (I'm assuming the turbo takes a big hit on fuel economy like a piston engine). Last time I had a car with under 16 mpg fuel economy, gas was well under a buck a gallon

What the engine really needs (IMHO) is a third rotor. If someone sold a reasonably priced kit for one I'd consider buying that and putting it in. Always wanted an excuse to tear into a rotory engine, I'm sure that would be a real learning experience.

 

^20B is all you need then....and only about 30k dollars and you can have it ready to go!...

 

I get exactly the same fuel consumption with the turbo as when it was NA - except when I'm going into warp drive of course .

 

Well researching the car on her would have helped you figure out the 8 is not a car for extracting a lot more HP. You're better off with a project or totally different car.

 

^it's possible to get lots of power but must ahve LOTS of money!

 

Most people don't see any changes in their fuel mileage with a turbo setup and in fact some report getting slightly better fuel mileage because the turbo increases the VE of the motor.

A 20b would most certainly be worse on gas. That's more or less a motor swap done only for power and nothing else.

Fuel mileage can be increased with a little tuning as the factory tune is VERY rich to account for safety and variations in gas.

 

^that's y u get rid of the cat and get the AP

 

Really? Okay, that makes the turbo a lot more interesting.

And I admit it, the car was a bit of an impulse buy. I didn't research it as heavily as I normally do, I was just really impressed with the handling. (and yes, I make enough money that I can afford to impulse buy one of these. That and I got a lot off of invoice, car salesmen fear me...)

 

^ Well, if you have that kind of money, think the 8 needs a third rotor, and have all that mechanical know-how...do the 20b swap then. Problem solved, and how.

 

^exactly..if you have the funds to impulse a 30k or more car then you can change out to a 20B or turbo or whatever u want...I don't know too many ppl that are just driving by a dealership and say "WELL I'm gonna buy a car today" and just do it..so I'd say 20B if you are looking for power! 15k or so but can save alot by doing it yourself

 

Even better than stock is highly likely as flashwong mentioned and i'd wager that a turboed renessis is way more economical , has more power , weighs less and costs way less than an NA 20b .

 

drama queen lol.....true though....but wont necessarily happen, thats the reason the pcm is limited to 10k rpm for safety reasons, imo nothing bad will happen unless you have some cheapo aftemarket flywheel. but i dont think a cheap flywheel is even made for the rx8.

 

/\ BHR Flyhweel is garbage. I thought you already knew that.











































Fools, it's the best one out there

 

now that was fking funny.

i was ready to bitch slap you!

beers

 

just buy a scatter shield

 

I have a really hard time believing that you can get more power than an NA 20b by sticking a turbo on a Renesis.

I've seen claims of 300-350 at the wheels with an NA 20b. Maybe that's technically possible with a turbo, I don't know, but what kind of boost are we talking about here?

 

300-350whp is well within the reliable range for a well tuned renesis pushing 10-12psi . This is on stock internals as well . I'm thinking a turboed renesis will have a broader power band than an NA 20b so would in fact be a quicker car even if whp was the same.

I'm not sure but i'd be very surprised if a NA20b gets anywhere near that hp on stock internals .

 

Chris from Esmeril supposedly ran ~20,000 miles at 414 whp with his turbo Renesis with only an ignition upgrade in addition to the turbo kit. No way you will do that with an NA 20B, not to mention the cost is drastically more to do the swap. Custom motor mounts, and a new transmission are just the tip of the iceberg for that swap. The only reason I could see doing a 20B swap was to do a large single turbo for 600+ hp figures or to field it NA for professional racing purposes. Aftermarket development has come a long way for the RX-8 even in the time since I got mine, just over a year ago. A reliable turbo or supercharger setup is relatively inexpensive and will make the car very damn fast.

 

I was in the market for a new car sometime this year. I was in the dealership for another reason and liked the car and figured, why not? So I bought it.

Yes I could drop in a lot more money if I wanted too. I could also have dropped double the money on a corvette or a cobra, or said screw it all and bought a Ferrari.

But then I wouldn't have money if I just wasted it all the time, would I? Which is why I'm looking for the best bang for the buck here. The turbo is actually starting to sound like a decent deal, though I'll probably not boost past 10psi. That will take some research to decide. If I drop one in, I'll probably buy the kit in the fall, august is just too hot around here for any serious wrenching.