bxb40

Did anybody try tuning the A/T RX8 up to 250 HP? Basically to make up for the horses lost when detuning the engine to less RPM and protect the tranny. I plan to get one this summer and I like the paddle shifters on the A/T. Any recommendations as of the ECU/mods to do it are welcome. Voiding the warranty if the ECU is changed/flashed can be avoided?

JimW

Try www.srmotorsports.com I know they have a 40 H.P. gain at the wheels with the G4 kit utilizing the 6 speed. With the auto you can expect about 30 H.P. less.

JimW

In reference to the above. If you modify your car and that part can be proven to damage related equipment, it will not be warranted.

JeRKy 8 Owner

Accordingto those guys they made 40hp by only adding stainless exhaust CAI and underdrive powerpulleys. They donthave any dyno figures postedanywhere that show this reported 40hp gain. They claim to have magically made 40hp w/those few components yet no one else who has added custom exhaust or CAI to their RX8 has reported gains anywhere near that high ifyou read through the posts on here.

Personally I thinktheir claims are just more marketting bullshit justlike Mazdas hp ratings for this car.

bxb40

I understand the power loss vs the M/T is due to less ports and detuning the engine to shift the max torque to lower RPM. So while we keep the RPM lower and modify the engine to make up for the lost power, would the tranny hold?
I guess a dealer can always blame after market parts for eventual part failures, so I don't plan to modify it from the begining - but would like to know I can do it in few years if I feel I need more power I've seen people selling the A/T to get the M/T - the price penalty is larger that the mods required to get 40HP extra.
Does anybody know if the A/T can handle extra 40HP? Regardless the way one might gain them (ECU or even a blower...)

RotorMotor04

I honestly do not think that the weak tranny the auto 8 has in it could handle the added ponies. If you want to get a real HP gain just go to the 6spd.

jonny

I've got an auto as well--I think you'll be better off focussing on aesthetics than performance right now--I drove the 6spd and it flies; but at the end of the day my wallet put the brakes on that (I got a killer deal on an auto). So after I finish my doctorate I'll just get a faster vehicle or maybe add forced Induction if its available for the auto RX8--or just get the 6spd like I wanted. Also; there are threads alleging an SMG and 5spd auto for the hi-power model in 2006.

robertdot

The detuning of the engine is NOT worth the paddle shifters. You cannot get that back later (not without a new engine or SERIOUS work). If I just HAD to have paddel shifters, I would seriously consider getting the manual and upgrading the tranny to a manual electric (like the rallye drivers use) later... like after warranty. I've never looked at prices because I still like to shift with my feet and hands. But, it should be worth it, since these trannies can easily take 300-400 HP and 500+ ft.lbs.

Or, if you don't know how, just learn to drive a manual. It's not hard, and despite what people say, it's only occasionally marginally annoying in stop and go traffic.

Now, if you just can't drive a manual (and by can't I mean you are incapable, not just unwilling), that is a different story. But, basically, it's about 2-3 grand extra (if memory serves, the base auto is ~25K and the base manual is ~27K) for the better engine. Any way I look at it, if I wanted a tuned engine, I would start with the manual. If I wanted a tuned automatic, I would start with the manual and replace the tranny. For the extra 2-3 grand, you verify that your engine can make 40-50 HP more, and will be more scalable to larger applications.

Gord96BRG

NO. The fewer ports (and 2 less fuel injectors) are because the AT low-power engine doesn't need them - they're only used between about 7K and 9K rpm. The torque/power curves for the low-power and high-power engines are actually almost identical below 7K rpm - yes, the torque is very slightly, marginally, higher for the AT low-power engine, but just very slightly.

The extra power of the high-power engine is ALL between 7K and 9K rpm - the low-power engine simply can't go there because of the RPM limitations of the Auto trans, and even if the trans could take it, the low-power revisions (like the simpler intake manifold, fewer fuel injectors, smaller ports) mean that the engine can't make more power at higher revs anyway.

SO - the only way to make significant (more than 5 or 10 hp) additional power will be with a blower of some sort. Even then, forum member rotarygod has posted a long article explaining why the low-power engine is a poor choice for power enhancements.

Regards,
Gordon

robertdot

You can read that here: Here's why the Auto RX-8 has little potential for power.

I don't know how long you've been reading the forum, but rotarygod has written several longer posts that are worth reading.

wakeech

and i still say that he's wrong, the A/T is a better candidate for turbo power.

it isn't that the A/T can't take the power, but it's the rpm of the hi-po motor that it has trouble dealing with. the 4 port configuration of the motor and the innately stronger transmission lend themselves better to the turbos that everyone wants.

rotarygod can blab on about how the 4 port 13B-MSP's have ports that are too small and whatever, but the port timing is better for a turbo configuration, and since everyone is gonna run a dinky little turbo at only 7-9psi the smallish ports are a-ok for it.

zoom44

rember also that it is low power engine because it was buit to be the lower power engine. people think that it is lower power because of the at. not so. it was invisioned as a lower power from the start. in other countries there is a 5 speed standard with the lower power engine. in this country it was decided they needed an AT to sell more cars. the AT they had available was unsuited to the high rpm in the hi-power car so the AT was put in the low-power.

edit: wakeech the only way i see for you to win this arguement is to go get yourself an AT RX-8 and boost it. so get one already!!!:p

wakeech

uh, an A/T?? forget it. i wouldn't turbo an RX-8 anyways :P... gotta have more redline

btw, about the arguement: don't think for a second that i actually think he's wrong, i'm just taking another side to the debate because i don't want the topic to get old, or ideas to become stagnant on this issue. i'm quite sure he's right, having actually seen and touched the motor in peices, studied it in ways i haven't yet, etc etc.

JimW

Your right! I should have stated that they claim 40 H.P.? Big difference. They also have a high flow cat and test-pipe with the G4. He indicated parts for the auto so at least they have these.

RotorMotor04

Do you think that the Renesis has a strong enough internals to withstand 7-10 lbs. of boost and still be a somewhat reliable engine.

bxb40

Thanks everybody. Seems that rotarygod did conclude everything already, so there are good news for A/T owners

"Here's the thing about the autos. For you guys that have them and want to turbocharge them, go ahead. The runners are limited in area when compared to the 6 port engines which simply means that you are also limited in max rpm as compared to the 6 port engines. Last I checked you already were. Nothing changes in that respect. You can still easily get the same low to midrange potential as a 6 port engine using forced induction. The tradeoff will be above 7000 rpm where you simply can't go. In reality since you guys will not need the larger turbo of the 6 port engine, you will have the ability to get much greater low to midrange power than the 6 port engines. Combine this with the transmission shift points and this should make you very happy. It will feel like a low end torque monster compared to the 6 port engine. The turbocharged 6 port engine however will feel like a high revving race engine by comparison."

Sure the RPMs will never be above 7000, but torque is the major complain for rotaries out of all I've read. And seems that it can be solved. I guess nobody FI or TC the A/T, but how much would that cost and who does it well in the US?
Thanks in advance.

RX-8 friend

A few words on costs:

The sequential transmission - looked into it for my RX-7 - $10,000+ (I can post URLs if interested).

Auto conversion for the high power - good luck finding one that can handle 8000 and up RPM - but the BMW unit (not really an auto as we know it - no torque convertor - would cost upwards of $15,000.

Turbo kit for the auto - $6000 range.

-MY- conclusion - go with the manual or wait until 2006 to see if you will be offered paddle shifters on the manual or a 5 speed auto. I suspect both will cost ~ $4-5 thousand more than current standard units. If offered the car would probably be packaged "fully loaded" so some of that cost would cover the extra "nice stuff" (leather, sunroof, Bose, etc.).

Japan8

Trust/GReddy is working with RE Amemiya to develop a turbo for the A/T (actually it's the same one as the M/T). It puts our 265ps or so... do a search and you should find some info I pulled from a JDM mag. The big concern with it is can the trans handle the power long term.

Japan8

And in Japan where the 5spd base motor is available, no one is building a t/c or s/c for it. No word of plans or anything. ALL tuners are working on the Type S 6port engine.

You can think rotarygod is wrong all you like, but I have yet to see evidence that he isn't and you are. I'm not rotary expert, but Mr. Nakamura of Knight Sports and Mr. Amemiya of RE Amemiya aren't ignorant or stupid when it comes to rotaries. Neither are the hordes of enthusiasts that are buying 8's. Yeah...as one magazine pointed out a cheap way for power is to buy a base and then drop on FI, but that has nothing to do with ultimate power potential and everything to do with wallets.

P.S wakeech... i did see your post saying you're just play devil's advocate. I'm just picking up the arguement...