anyone using JDM 5 speed transmission for track car?
 

I'm installing a new motor in the near future and was considering doing a new tranny also. Cant decide between S2 or JDM 5 speed. it will be paired with a 5.1 diff. if you have one for street or track, what's your feed back on it.

The 5-speed is a must for a turbo car. Strength of transmission aside, the longer gears are necessary when dealing with a 4.44 rear end.

But for NA puproses, none of that applies... In short, this has been of no help to you :D:

so the 5 speed is definitely stronger?

gear ration comparison
jdm: 3.483, 2.015, 1.484, 1.000, 0.762
S1: 3.760, 2.269, 1.645, 1.187, 1.00, .843
S2: 3.815, 2.260, 1.640, 1.177, 1.00, .843

from the few tracks that I have driven on with the rx8 so far (stock s1 tranny and diff), i can't imagine any tracks where i would need to use 6th gear. but that might change once i install the 5.1 diff?

the s1 and s2 5th is 1:1, and the 5 speed is 4th for 1:1, which mean i probably wont use 5th on the 5 speed neither.

Brett has a turbo, a five speed and occasionally tracks his car. Hope that helps

What do you think? Look at the difference in case size between the 5-speed (left) and 6-speed (right)

https://cimg8.ibsrv.net/gimg/www.rx8...f0fca2f004.jpg

My understanding is that the 5-speed is internally identical to the FD RX-7 TT transmission (and therefore the same as the FC RX-7 TII trans). If that's the case, it's very strong - it's what I'm using for my turbo Duratec build.

JV

Damn near the same externally as well. The bell has slight changes and some significant changes with the tailhousing, however the inner-case is almost identical to an FD. The FD is an enhanced version of the TII (S4/S5) transmission.

If a 5spd was readily available, I wouldn't be opposed to it. The FD transmission is still one the best I've ever shifted.

is the 5 speed a direct swap? same clutch ect.

Should be. I had to grind off a dowel that was on one of the upper passenger side bolt holes, but that was to fit a REW iron. May be a perfect fit for a MSP rear iron....

Sorry, I don't have any experience with the 5-speed. But you mention the S2, which I do have.

The S2, with the 5.125 final drive, is a fantastic combination in the RX8. The transmission is super stout, and the gearing is awfully good for the track. 3rd climbs out of most corners incredibly well.

I wanted to note that the 5spd does use a different clutch and flywheel (I visually confirmed this against a European 5spd/4port engine). I suspect that you can use a 6spd clutch, as long as you are also using a 6spd flywheel (or 6spd aftermarket LWFW). Your potential pain point will be input shaft spline count between 5spd and 6spd. I suppose it is also possible the clutch/flywheel diameter could differ, leading to possible bellhousing interference.

good to hear that. any issues with increased diff temp with the 5.1?

I am using the JDM 5-speed in my track car, 13B-REW engine, Rx8 Clutch. Fit right in place. Works very well! But I am turbo'd making 464whp. Someday would like to go sequential. But the 5-speed will do for now.

5spd track car
 

Here is my RX8 at I bought from a friend who was endurance racing it with the original 6spd, but a few gearbox issues and a couple of engine failures he had a specialist build the current engine and swapped in the 5spd. The issue I have is the 4.44 is too tall and I need to get a 4.78, so if anyone has a contact to get a hold of a 4.78 message me.

Anthony
Golden Rotor Racing & Rental


https://cimg2.ibsrv.net/gimg/www.rx8...fdb2f4f2e5.jpg

i ended up with a JDM 5 speed and never got around to putting it in,. . i do feel like im missing out though

Just for the record because the information is becoming harder to find on teh intrawebz as time passes on, but the JDM 5MT has different 3rd &5th gear ratios than the EUDM 5MT transmission

JDM 5MT (note: identical to USDM FD3)
1st - 3.483
2nd - 2.015
3rd - 1.391
4th - 1.000
5th - 0.806

EUDM 5MT
1st - 3.483
2nd - 2.015
3rd - 1.484
4th - 1.000
5th - 0.762 (S1), 0.791(S2)

these attachments are from a 2008 Mazda JDM sales brochure and a Mazda press kit for the British International Motor Show 2008 (BIMS08)


https://cimg2.ibsrv.net/gimg/www.rx8...08b9cc805.jpeg



https://cimg0.ibsrv.net/gimg/www.rx8...c5c480721.jpeg

My collegue complains about his EUDM 5speed. It has a horrible drop in rpm from 3th to 4th. He is looking to swap in a 6speed. But by the looks of it, a jdm 5 speed would be a bit better too.

Both of those spec sheets are for S2 rx8s .

Not sure why it matters since the S1 and S2 used the same 5-spd manual transmission. Unlike the 6-spd, it didn’t change.

UK S1 brochure attached

.

Ok ...good to know .

Well actually, the UK S1 brochure is showing a different 5th gear ratio: 0.762

They did update the R&P from 4.444 to 4.777 on the UK S2 5MT too. So overall less steep. The low-power engine needed that.

.

This shows how much more beefy the 5-spd PAR straight dog-ear gearset is for abusive/competitive purposes


https://cimg0.ibsrv.net/gimg/www.rx8...7d27e4e2c.jpeg

https://cimg7.ibsrv.net/gimg/www.rx8...0104ca830e.png


https://cimg3.ibsrv.net/gimg/www.rx8...865ac803a.jpeg


https://cimg4.ibsrv.net/gimg/www.rx8...f4deb83c55.png

Yes, I have it and will be putting it back in my car. I took it out cause the car was lazy. It turned out that there was a vacuum leak and the engine was running like a 4 port. Anyway, someone we all knew who race a Champ/Chump car RX-8 ran his with a 5 speed at Daytona and never had a gearbox failure. I see it as one less gear change and just have to get drivers to use 2nd gear for those slow corners.

Yes, the 5spd is heavier than the 6spd. While renting my car to others for endurance racing I had to keep reminding the drivers that the gearbox is an egg, so take your time with the gear changes.

Well I’m looking for an RX8 5-speed. It can be broken because
the PAR gearset shown above will be going into it.