FC3sinfiniIII

If using a 2JZ 6spd tranny on a 7, will it be require to get the 2jz driveshaft and diff?

Ice_Wolf

My question is why would you want to use the 2JZ transmission in the first place?

But yes, you would need a driveshaft to spline correctly to the transmission and that's going to bolt correctly to the rear differential. Obviously the best way to do this would be to use the 2JZ driveshaft, but most driveline shops can custom make driveshafts to fit your setup, even if you kept the stock RX-7 differential and use the 2JZ tranny. This won't be cheap, but it will get the job done most of the time.

Sideways7

iTrader: (7)

Will it even match up to a rotary engine?

Ice_Wolf

I very highly doubt it will. Also, wouldn't you need a different flywheel setup to go with the 2JZ transmission? Seems to me that if you really really wanted a 6 speed tranny, your better bet would be a RX-8 transmission.

RETed

No.


-Ted

Ice_Wolf

Ted, your advice always amazes me. I'm blown away.

But he is right.

FC3sinfiniIII

Ok, Well see i would like to go with 6 gears rather than 5 and also i want longer ratios. I also heard that the supra tranny is stronger than rx7.

V8slayer

get the power to break rx7 trannys then werry about it

Black91n/a

Well you might be able to do it by making an adapter to bolt the FC bellhousing to the tranny and use a custom clutch that's FC sized with a Supra spline on it. You'd need to figure out if the input shaft is even long enough, then figure out what to do with the pilot bearing. If you're lucky you can mill down the input shaft if it's long enough, that way you can use the stock pilot bearing with the different tranny. As mentionned, you'd need a custom driveshaft with the Supra spline on the input and the FC flange on the diff end. Then you'd have to figure out if the shfter is even in the right area and if not, then either move it or cut a new hole for it and live with it in the new spot.

So basically it'll be a big job and could end up being really shitty.

If you want longer gears change out the rear end gear to a 3.9:1 ratio. It's a lot less work. If you must have a 6 speed, the RX-8 one bolts onto the 13B, but a different driveshaft may still be required, the shifter might not be in the right spot and it's not that strong.

MaczPayne

iTrader: (5)

Pfft, 6 speeds are overrated.

My semi truck has 20 gears, that's some mad tyte **** there.

FC3sinfiniIII

Well, i just want 6 gears and longer ratios. For the way i drive the shorter ratios are too annoying

rx7racerca

iTrader: (1)

Sell the Supra tranny, find an RX-8 tranny (or possibly a '99 and up Miata 6spd box? I think they started having 6spd about then), or just swap to the taller differential as suggested earlier; you've got way too much time and money on your hands if you're going to do all the engineering and fabrication needed to mate the Toyota box to your engine, including an adapter between the engine and tranny, a way to match a 7 clutch to the different input splines on the 2jz, and almost certainly a way to mount a starter in the proper 7 location relative to the flywheel, engine, exhaust, etc. And the shifter is not likely to be in the right location (although as noted above, an RX-8's might not be either).
Try a search, I'm pretty sure the RX-8 swap has been done; you might need custom tranny mounts and likely need an custom driveshaft done, with an RX8 yoke on the front and 7 on the rear, but that's relatively easy and cheap. Check the dimension from the front of the 8 tranny to the shifter to get an idea if it might work; if its off significantly, you'll be looking at relocating the motor to put it in the right spot (also more time and trouble than it's worth), or having to adapt your interior and possibly cut the transmission tunnel.

Jager

iTrader: (10)

You don't need 6 gears and whyw ould you want long gears? Swap in a 3.9 rear and you'll be happy (although disappointed).

Sideways7

iTrader: (7)

Ok, so you don't want short ratios, but you want a 6-speed. You do know that 6-speeds have closer ratios than 5-speeds, right? The rx-8 tranny basically has the same rations, but with an extra gear in between 2nd and 3rd, or something like that If you want taller gears, then get the 3.9 rear end. If not, then its way out of your league.

gxlbiscuit

the fellas are right 6 speeds are closer ratios.. you are in the wrong area work with the rear.

cpubugs

Well said. lol

RotaryResurrection

iTrader: (8)

Also, the rx8 trannies are known to be fairly weak, no stronger than the FC's nonturbo tranny. The stock rx8 makes about 210hp and 150tq at the wheels on a good day and they are having all sorts of issues with them even at those modest power levels. There is already talk of trying to retrofit the FD 5sp into the rx8 for a stronger option.

The FC already has quite tall gear ratios...the car is *theoretically* geared to reach about 165mph in stock form (redline in 5th, depending on model) but it does not have the power (unless heavily modified) to reach that speed...so why are you trying to *theoretically* gear your car even higher?

Most people go the other way, with a shorter gear ratio for faster response, and higher rpm's at a given speed to keep the engine in it's powerband. OF course this hurts your theoretical top speed (in reality it makes it about the same as your realistic top speed) as well as mileage and engine wear.

IF you're thinking that by gearing your rx7 way up to keep the rpm's down and perhaps get better mileage or something, it won't work. Rotaries are more inefficient at low rpm's than mid rpm's...the sweet spot for cruising is in the 2-3k range for mileage. If you add too much gearing to your car, the engine won't have the power to take advantage of it anyway (it doesnt have the power to take advantage of stock gearing).

Seriously...under what circumstances is 150-160mph (theoretical top speed with stock gearing) not enough? If you can't beat whatever you are racing by 120mph, you're not going to beat them at all unless you go buy a single turbo supra or a bike.

1989_N/A

Ted Told me once, that if your wanting big power and a strong trans to go with a Chevy TH400 trans. Its an auto, but it would hold up Im sure, as I have yet to see Ted give bad advice.

As said 6 speed trans have shorter gear ratios and would totally defeat the purpose of what your wanting. If your wanting to use a trans for longer gears, you would want less gears, not more. Hell if your going to try mating up a 2JZ trans, you might as well mount a 4 speed or even a 3 speed if your feeling ballsy. lol.

But seriously, swap your rear-end gears. That will give you a better built drive train, instead of afro-engineering something thats gonna suck anyway.

TitaniumTT

There is talk of a Getrag retrofit kit. I have yet to see it materialize (HINT HINT)

There are sooooo many myths about the Aisan RX8 6-spds so I'll pass on some truths that three people who modify these for racing have told me.

1 - yes the trans is "weaker" meaning it will break easier than a Type R box
2 - in reality though they can be made much stronger than the N/T box and much stronger than the Miata box that routinly sees close to 400rwhp from the Flyin Miata guys
3 - the RX8 gears are ~35% BIGGER than the Miatabox gears
4 - abuse any tranny and it will break rather easily
5 - the big problem with the Aisan trannies have always been thier second gear hub/crown/sync - even on my '98 Cherokee with an Aisan AX-15 the 2nd gear sucks ***.
6 - FACT (I'm taking it as fact becuase 3 different knowledgable people with hands on experience rebuilding and modifying these trannies for racing have told me) what generally causes these trannies to fail is powershifting into second. For whatever reason, sloppy shifter, sloppy driver, worn sync, to much force is put on 2nd on the hub starts to seperate/double over letting a detent ball pop out of place. This generally happens at redline so you can imagine what a SS detent ball will do with an input shaft spinning @ ~ 9k.
7 - Fact - the RX8's shifter location is ~4" forward so you're shifting inside your stereo or move the motor back or modify the interior.
8 - you will definately need a tranny mount & driveshaft
9 - you will no longer be able to keep your speedo
10 - emmisions concerns become an issue with a few switches

FC3sinfiniIII

Well, I do not care about acceleration that much, i do not like 1/4 mile. I like time attack. I rather prefer the longer gears and 6spd for time attack. I do not care if the 6spd has closer ratios i'll make it longer

RETed

You don't seem to get it through your thick skull.
It's a fricken waste of time.

Most 6-speeds just add another gear in the middle, but 5th is still 1:1, and 6th is still overdrive.

So you just add one more fricken gear in the middle, and everything else stays the same.

1st gear is the same.
5th gear on 6-speed = 4th gear on 5-speed.
6th gear on 6-speed = 5th gear on 5-speed.
The 6-speed replaces it's middle 2nd, 3rd, 4th for the 5-speed's 2nd and 3rd gears.

You end up just shifting more times in the middle.

Yes, there are rumors that there's a bell housing adapter for running a Supra trans on a rotary engine, but I've never seen one in person.
Which is most likely that those things are one-off projects and not mass produced.

You're not changing the "outside" gears.
You're only messing with the "inside" ones.

On top of everything else, that transmission is very hard to find.
We're talking thousands just to source a good, used one.
The Supra guys are having trouble trying to find replacements.


-Ted

MaczPayne

iTrader: (5)

You can try Advance Adapters and see if they have one that will fit... but they're not cheap. Expect to fork over tons for them. If you don't have money, and I mean it; Don't try it.

TitaniumTT, it's Aisin, not Aisan =P I'm also a Jeep guy.

doridori-rx7

iTrader: (3)

NO ONE prefers MORE gears for time attack. Don't act like a noob, listen to others here, final drive ratios are our friend, use them.. wisely.

Black91n/a

All the road racers out there go to much shorter gears when they change, unless maybe they've got a 1:1 5th or something like that. The guys running in ITS use a 5.12:1 gear as the hot setup. For the TII housing the selection is limited, I beleive it's pretty much just the 3.9:1, the 4.1:1 or the 4.3:1. Taller gearing will make you accelerate slower, making you slower. You really want to gear the car to top out at the maximum possible speed on the fastest track you run at. Chances are that's already faster than the car can go. Having a geared top speed any faster than that is just a waste and will slow you down.

imloggedin

..someones been watching the fast and the furious