johnsocal

Im wondering if the 2005 version of the RX8 with an automatic tranny might see 250 HP and maybe a more efficient CVT-like tranny to distribute power better then a traditional slush-box. I would be sad to see a Neon SRT kill a RX8 at a stoplight drag.

note: I know if one wants real performance they should stay with a manual but one cant deny the market for more powerful engines and better automatic trannies to really help sell the RX8 in high numbers and make it profitable for Mazda to make it.

Hercules

If one wants real performance they should pay attention to numbers other than the straight line ones... *sigh*

I think that if you want a drag racer, or a car that can win on a strip... then you are lookin at the wrong car. And that's echoed in a lot of posts on this forum.

Take a search first and see what this car is about, then decide if it's for you.

Mak

Yup If you want a car to drag the RX-8 ain't it. Look for a car with alot of torque.

johnsocal

Hey guys thanks for pointing out the obvious. I know that the RX8 is a well rounded great handling sportcars and it isnt a 1/4 mile dragracing musclecar.

Does anyone if its Mazda automatic tranny design is the reason that forces them to cut the HP down on the engine and is there any hope they might increase the HP in the future?

Hercules

Yes it is, because maximum horsepower comes at 8500 RPMs, a rate that torque converters find hard to adapt to and thus unless you want a really expensive car, will have to be detuned.

SMG type of a transmission would also work for the RX-8 but then you're talking about even more money than the manual costs... and the idea with this car is to keep it reasonably affordable.

Skyline Maniac

I recently read a Japanese magazine, which stated the automatic version of the RX8 actually has better torque response than the manual tranny version. According to the article, more restrictive intake manifold improves torque, which is essential for the automatic transmission. I am not sure if Renesis has variable air intake system, but their explaination seems to make sense. I seriously doubt Mazda decreased power on the automatic model because they couldn't build a tranny strong enough to take the added power.

cueball

Yes they would. When they attempted to hook a auto up to a full power car, they kept blowing the torque converter. Why else would they do that?

Sputnik

It wasn't because they couldn't, it was because they were not going to spend money developing an auto that could handle the revs.

---jps

boowana

I can't say for certain but I had heard from a very good source that there will ultimately be a "sequential 6-speed transmission available that will handle the RPMs of the Renisis engine. My guess would be to loook for it in the Mazdaspeed veriosn which is probably 24 months or more out into the futureafter deliveries of cars start here. The earliest then would probably be July, 2005.

Gord96BRG

They didn't decrease the power of the engine - they decreased the rev limit. The auto trans can't handle 9000 rpm, the problem is revs not power. 210 hp is what the engine makes at the transmission's rev limit of 7 thousand something rpm. There's no easy way to make 40 extra hp at 7000 rpm - so NO, there's no way the current 4 speed auto will get a 250 HP engine.

Further to Boowana's prediction - along with the 6 speed SMT for a 2006 model, I've already predicted that Mazda will have a 5 speed auto trans in the 2006 RX-8 (in a separate recent RX-8 auto thread, I bet Sputnik $20 on this ). If someone wants a better auto trans RX-8, they really should wait a year or two.

Regards,
Gordon

rototlewski

hey I know some of you guys have seen the press kit! its not just the rev limiter its the intake ports are timed slightly different plus the auto doesn't have the aux 5 and 6 ports plus it doesn't have the aux intake track that opens at 7250 or around there.

I haven't looked at the press kit in like 4 or 5 months but im sure thats why the power is lower, the reason i know why they are not there is because of the auto but because of that you couldn't just replace the TC and get 250 hp you'd have to replace the entire drivetrain

wakeech

this is a bit of a misnomer: it's not "more restrictive" as it is more efficient at lower flow rates... the smaller diameter and longer length help the engine breathe more effectively at lower rpm.

hey!! i won that thread, it's officially "tertiary ports" :p!! AHAHAHA!!! :D :D

btw: you're right, the lo-po motor has only 4 ports, and the intake system is entirely different (less paths).

Gord96BRG

Sure you could add the extra ports and the third intake path and get extra power from 7250 to 9000 rpm - but why bother??? The transmission can not handle input shaft revs that high without blowing up. It has nothing to do with the power, it's the rpms. Those intake mods won't make any extra power below 7000 rpm, and the transmission can't operate over 7000 rpm.

Your desire for extra power via the manual trans intake specs is incompatible with the capabilities of the auto trans. Just buy a manual trans car, fer cryin out loud!!!!

Regards,
Gordon

MikeW

Yeah maybe if the rotor width is 100mm

j-apex rx

you are all saying the tranny can't take more then210 .so why the rx7 from 93 to 2002 that had auto tranny had 255 to 265 hp .you tell me the answer to the question then i will beave it.

lefuton

i don't follow the auto-tranny stuff too closely but i thought it was the torque converter that could not handle the upper rpm's

Hercules

I am not even sure but I'd bet that it's because since the RX-7 used a turbocharger, that the power was created at a much lower RPM than in the RX-8.

wakeech

read the thread again: the problem is RPM. because the tranny can't take much more than 7500 or 8000 or whatever the breaking-point is, they've detuned the engine to 210, which is why it's different from the hi-po motor.

it's not in the power, the power is a symptom of a rev-averse transmission, not the other way around. if the RENESIS had the sequential twin turbos from the 13BREW (thank god it doesn't) the tranny could probably handle the extra torque, and you could have 250 horses or whatever at 7000 rpm, and everything would be peachy.

if you want tons of power in the 4-port motor, if you're serious about it, look into FI as an option, as its a far better candidate for it than the hi-po 6 port.

Haris

Don't acura NSX's auto tranny redlines at like 8K/8.5K RPM? I think mazda could have done this if they wanted to.

Haris

Could mazda give auto tranny like 7K RPM but with 250 HP it would still be fast? It just seems as mazda didn't even care about auto tranny but just to make extra sales.

rotarypower

goddamn wakeech.

your wealth of wisdom and knowledge never ceases to amaze me. i'm 18 and i dream of knowing as much about cars as you do. how old are you and how'd you get to know so much about cars??

your #1 fan

Hercules

Doesn't the NSX cost 90K?

I think that might have something to do with it

wakeech

...i italisized the important bit: the NSX is, what, a near-exotic halo car at nearly double the price of the RX-8, which is suppost to be a volume sales sports car liek the Miata is for Mazda: there is no way they would sell a tranny 2k more expensive to produce (never mind the Honda-sized budget to engineer one) 30 more horsepower in the non-purist-enthusiast model anyways, right??

and secondly, i dont' think that Mazda doesn't care about the auto, but with this model they're targeting a different kind of buyer: someone who would buy an Accord V6, but wants somethign that can handle, and looks good enough to impress the ladies. it's not for the purist-enthusiast, it's for the sometimes arm-chair-fantasy-racer (hey, i am too: i don't think there's nothin' wrong with wishing you were Kimi) who'd just like to have a nice, refined, easy driving true sports car. it's a wankel motor too, but that's not the only selling point on this very well-rounded vehicle. my point is that the auto doesn't have to be the fastEST: it's not like 210hp is slower than any FWD sports coupe in that price range anyways (RSX-S, Celica GTS... to tired, can't think of other examples).... in fact, i think a 210ps 5speed would be bloody fast and would certainly be enough car for me, had i the choice to get anything.

wakeech

ahahaha... don't tell Sputnik, he'll yell at you for how wrong you are (about me knowing a lot)

i'm 19, and i just kinda really got into cars with Gran Tursimo (believe it) and F1... that got me started, then i fell in love with the rotary... i've just got a thing for engines: they always seemed like magic (back in '99, i couldn't fathom how a car engine actually worked... i literally knew nothing about the mechanics) to me.

now i've learned, and i'm still constantly learning new things all the time... to really get the basics, start with motorsports: it's automotive performance distilled to its most raw elements... speed isn't complicated once you get down to it: it's just got to be lighter, stronger, and faster. the tricky bit is how to get it done.
...road cars on the other hand pose a far far greater challenge to the car designer (IMO) with all the countless comprimises and very subjective features of design (like "beauty" and whatnot).

the old tech forum i used to haunt (most stuff blew over my head at light-speed) was www.f1mech.com , which has sadly disappeared almost 1 year ago i believe... i've not checked back in probably 8 months, and only thought of it now that you asked (checking site now as i write this)... nope, still the same as always... *sigh*

anyhoo, yeah, thanks :o

Sputnik

That's an inside joke, btw...

---jps