Hey everyone, I started re-building a new transmission today that will solve many people's problems. This transmission is actually and RX7 FD unit, although it's a 5-speed, I think the ratios are much better than the 6speed. This is actually kind of a info-DIY thread. The problems with the FD trans is that:
1.) the ppf frame has a slightly mounting point for 2 of the screws, you would have to alter the ppf. Forget about it...
2.) the clutch is inverted compared to ours, you would also need to alter the clutch line, new slave cylinder unit. No need...
3.) the shifter is in the wrong location. No problem...

Here in Europe we have a low power model with 192hp(basically your automatic version) to lower the cost. This version is offered in automatic and (only) a 5-speed manual. The 5-speed is the generic R15M-D which is also used in the RX7 FD. Now I'm not saying that it's the exact same gearbox, I don't know about the internals, and how strong they are. From what I know it's just the MX-5 equivalent, which is crap. So, I got a used damaged unit from the low power RX8 and switched over the parts. The outer casings(minus the bell housing and rear end) are the same, it's the same transmission layout. So the bell housing fits perfectly and has the clutch style that we need. The rear casing which houses the shifter also has the same location that we need and also the correct ppf mounts. Like I said, the is the perfect setup since those parts are from the RX8. I'm not 100% sure about this but, it can now use a FD short shifter upgrade or those el-cheapo versions that are found on ebay for like $40.

 

A couple more

 

Cool, I will probably upgrade to a 09' + 6 Speed tranny.

 

Very cool!

 

Have been looking for a used JDM 5 speed here for a while now . Think it would be the perfect upgrade tranny for any FI rx8 .

Good thread man.


Also : i checked with ASH8 and he says all the internal parts are identical to the FD transmission .

 

Which internal parts are you talking about and JDM tranny? The stock RX8 5speed? If so, I don't think they are stronger as many people break them here.

 

I broke my share in an FD3, IMO it's not that good of a trans but the gear ratios may be more preferrable for FI (not for NA though except the steep 0.73 OD gear might give better highway mileage)

 

Nice find!
Keep us informed on how the swap goes.

 

He says the JDM 5 speed tranny (which should be the same as the one you are talking about) has same internal parts as the FD tranny .

 

Nah, don't think so, I'm pretty sure it's the same one we have here in Europe. A lot of stock cars break these boxes and then upgrade to the 6speed, it's the same gearbox that the mx5's have. I've never broken an FD box(a couple of syncronizers sure) they are good for 500rwhp. Of course it does depend on driving techniques and also a lot of FD 20b's still use them so... :

 

hmmmm - more research ....

 

I broke a perfectly good 6speed with 2runs, it's a piece of ****. I had a FD for 9years, not once did I break it...

 

Back to the subject, I finished the trans today, and everything went great except for the shifter. I also had to use the main shifter rod from the 8's since it's a few inches shorter and I didn't want to cut anything. The problem with the short shifter is that the movement is restricted by the shifter housing, but nothing a little milling won't take care of. I'll try and finish that up tomorrow.

 

has me puzzled ....

 

Not all the same ratios, not all the same parts, not the same gearbox. There are many different versions of the same transmission, some are found are cars(n/a, turbo), some are found in pickups(2x4,4x4), doesn't mean they are the same internal parts.

RX7 RX8 RX8

5speed 5speed 6speed

Gear Ratio 1st 3.483 3.483 3.760
Gear Ratio 2nd 2.015 2.015 2.269
Gear Ratio 3rd 1.391 1.484 1.645
Gear Ratio 4th 1.000 1.000 1.187
Gear Ratio 5th 0.719 0.762 1.000
Gear Ratio 6th - - - 0.843

 

Damn son, nice find One thing has me intrigued, so many people have issues with the stock tranny and i have not had one issue with mine putting down 350kw, my main problem is just being able to shif at high rpm, though i dont think the box would hold any more than that. if this works does it mean we will be able to put an aftermarket gearset made for the FD? if so then this will allow for even higher power level and rpms.

 

Thanks, I guess it's a pretty rare thing to not have one blow with that much hp, although it also depends on the driver as well. When you say you can't shift it at high rpms(which I also saw with mine, especially 4-5th)other people will make it shift and destroy it. I'm rebuilding the engine right now so I won't be able to get back with any solid info. There are another 7-10 8's here rew's and they all have stock FD trannys. OS Giken makes a nice set for the FD if anyone is interested:

- 1st: 2.578 (3.483 OEM)
- 2nd: 1.772 (2.015 OEM)
- 3rd: 1.289 (1.391 OEM)
- 4th: 1.000 (1.000 OEM)
- 5th: 0.821 (0.806 OEM/Japanese late transmission)

 

Two problems.
First, at what rpm do you plan on shifting at? FD trannys are known for shifting out of powerband....
Two, if you're shifting at a high rpm, to avoid going out of powerband, how well will the FD tranny hold up to the aforementioned high rpm.

otherwise, nice find, and nice swap, you're doing it right :D

next best option before spending the chunk of cash on a T56.

 

Well, I used to shift my car(FD) at about 8400, but I'm sure there are many that run more than that. If you take into account though with +xxx amount of horsepower and torque (that you'll never see on the renesis) I doubt it'll run into a problem. In fact after opening up all three transmission, I don't see anything different(better) on the 6speed that would indicate it'll run higher rpm's better than the fd's. I'M NOT saying to anyone go out and find parts, because this is the best setup! This is an experiment that I want to do for myself, as my transmission didn't hold the power I was putting out. I am not a business which is trying to sell something, I'm just someone who gets happy when I do something I haven't seen and would like to share with everyone. I hate it when I think about something and search and search with no results. Like I said before there are other people here in Greece with FD engines and FD transmissions, unfortunately they're part of a different crowd, which I'd rather not have dealings with. From what I know their setup has worked out great for them, and also Firecran and Deathwalkin are using these transmissions as well. I just wanted to do it differently by not changing engine mounts and bring the engine more forward for shifter clearance, and keeping the stock clutch style setup.

 

I'm still running the renny 6 spd. but I'm interested to see how this works for you.
I would prefer to run a 5 spd. Well see with your results.

Thanks again for posting.

 

Oops, thought you had it as well. I know for sure the Deathwalkin has a 5speed.

 

fantastic thread and superbz job and info !!!


KUDOS !!!

 

Any updates?
Is she running again?

 

Does the FD input shaft length match up properly? I ask because I know the FD input shaft length is longer than that of the Turbo II and wonder which tranny (FD or FC TII) would match better with the RX-8 Bell Housing.

Thanks.

Chris

 

FD and RX8 input shafts are dimensionally the same as far as general fitment goes

there's an old "genius of the week" thread on here where that particular genius of the week chopped up an FD box to make it fit on the RX8