How tough is the RX8 6-Speed transmission?
 

Hello,

I have this RX8 that I got without a rotor in it. I'm swapping in a 1JZ-GTE in it now. I wanted to ask how strong the 6-speed tranny was? Because if the tranny is weak, i'll go with a 5 speed RX7 one instead of this. I'm going to be running raised boost on stock twins with a FMIC and few upgrades so something like 300-330whp looks like what I'll have. Am I going to have problems with it?

Regards.

There are lots of people who boost the 13b and get those same numbers. There is also some threads here talking about the benefits of the RX7 tranny. So really it depends on your goals. From my limited experience with the 8 I would say that you could use the 6 speed for road use and maybe some track days but the RX7 tranny will be slightly more bullet proof....

Should you not worry about torque with the trans, rather than horsepower?

The current 6-speed tranny shall be fine with those #'s.

For sure, I was refering to torque and hp. But while I'm throwing my two cents around I'd like to go on record saying that if you build any type of powerful machine you should build it right and make sure things like your trans and rear end can Handel the hp. In otherwords no cutting corners. If the 6-speed works but is not the best I would never use it.

the current tranny is just weak. even at non-FI levels.

How? I haven't been disappointed at all yet. I am stock but still.... elaborate please.

spend a few minutes searching for tranny related threads.... synchros, shift forks, etc

if you drive it a certain manner, sure it'll last. if you drive it differently, you could loose it immediately at those torque levels.

A good example.... theres a N/A member here who competes AutoX, he's been through like 4 or 5 trannys... Now you can say "i wont thrash my tranny" all day long.. but remember stock levels being used to full potential can destroy this thing. if you are making twice the tq, your not gonna have to drop the hammer.... just "get on it a little" and you'll be putting the same stresses on the tranny that you'd see in abusive N/A driving

^TRUE

What are you doing with the car, I've heard some people who are not N/A don't have problems but I wouldn't know if they had other supporting mods. I'm aware of one guy around my area who uses the stock renesis trans and he is/was FI but he has "minor issues", whatever that means...

Run on the track for 15 minutes hard, you will notice the gears get very stiff. It's nearly impossible to grab 3rd gear once the tranny overheats (which happens after a good 15 min session)

Turbo cars can make 2-3x the torque, the tranny will fail if you put too much stress on it

Shift it like a wuss and you won't have a problem. Shouldn't be too difficult for someone swapping a 1JZ into an RX-8


.

^ rough.

:lol:

im on my 2nd tranny.

The Second Gens use the Trans from the NC Miata.
Miata guys think its the beez Kneez, but Some guys with 09's Rx8's have already had a Syncro or bearing replaced. Its an RPM issue more-so than a Torque issue.

ITs like Tofu.

I like it, tastes good.

Thanks for the input people. I've been told if I use a decent clutch and don't drive like an a$$ I should be fine. I hope to see it live long. I'll post pictures of my car once it's ready :)

Good Luck :)

sounds about right . I've had those power levels for 8 months or so now and it has been OK . I never speed shift or go full throttle in first gear and generally try to treat the tranny like a granny .

I'm not entirely sure WTF your trying to say, but I have four countershafts with all the 2nd gear teeth torn off of them.

Can you please explain to us how this is a synchro issue?

^LOL

Anyways, You can shift "granny-like" but at those power levels the urge is...........

funny,

not had that issue.. did two 20 min sessions back to back. the track was a 3rd and 4th gear track..

btw, temp on that day was in the mid 90s.

beers :beer:

I heard using a 350z tranny is a better choice. Still a 6 speed but can handle the tq/hp.

And I do realize this is an old thread. Just throwing my couple cents in. Looking for a response.

S2 trans is your best bet, it's the most common and proven swap. And most track guys use it here, or the FC 5 speed depending in what gearing they want.

R-154 transmissions are cheap and adapter plates are available for the 1jz. Why not look into that if you're worried?

5 year bump, yo.

the S1 trannies can handle about 300wtq but don't take well to abuse such as launches, puck clutches or hard shifting. the turbo RX7 transmissions have much less positive shift feel but can handle about 50% more torque.

it would probably be better to use the appropriate transmission for the engine to avoid adapters and whatnot.