Just picked up another slightly used PAR close ratio dog-box gearset, but this one is for the S1 6 spd.

Came out of an RX8 track car with a high rpm NA 13B with peripheral intake that was down in the Dominican Republic. Gear ratios are setup more for a peaky NA engine (obviously) than turbo, but 1st and 2nd (2.464, 1.889) are still appropriate for autox with a turbo (Street Mod). Whoever made the gear choices kind of boffed 4th gear ratio by one tooth on the ratio progression from 3rd to 5th though. Which unfortunately one side of 4th gear is machined/integral to the main shaft, but more cost to change than I care to invest since it’s not that big of a deal.


https://cimg5.ibsrv.net/gimg/www.rx8...a7ab3fbed.jpeg

Recently bought a 2004 jdm 5 speed through J-spec auto came in very clean with near new starter + clutch slave. Mine came with the flywheel and clutch assembly, which is actually slightly different than the US rx8 flywheel and assembly.
https://cimg1.ibsrv.net/gimg/www.rx8...1687c71b3c.jpg
Here is the JDM flywheel on the left compared to a stock US flywheel on the right. The JDM flywheel is noticeably heavier.
https://cimg8.ibsrv.net/gimg/www.rx8...91ba3a521d.jpg
The JDM flywheel(left) also has standoffs for the clutch assembly.
https://cimg0.ibsrv.net/gimg/www.rx8...d9a49bd536.jpg
The US clutch assembly(top) is taller which makes up for not having the standoffs that the JDM has
https://cimg2.ibsrv.net/gimg/www.rx8...a66e9be755.jpg
Other than the flywheel and clutch being different, the only other things I noticed were that the electrical connectors were in slightly different locations. My harness had more than enough slack. The rear 02 sensor connector on the opposite side also had a heatshield. I have yet to put fluid in it, trying to figure out what I want to run, but from what I remember there are 2 fill and 2 drain ports. I did test the US driveshaft while I had everything out of the car, and it fits like a glove. I am going to be using the US flywheel and clutch assembly along with my own starter since it looked to be in slightly better condition.

nice, interesting that the flywheel and clutch assembly would be different. whats the weight different between the jdm 5 speed tranny.

I didn't notice much difference between the trans picking them up by hand. As for the flywheel it was a very clear difference, maybe I will weigh the flywheels tomorrow.

despite the differences, it looks like the throw-out engagement point is the same, but the 5-spd is not supplied with the high rpm operation (192hp mid-power engine), so it’d make sense to have more weight and smoother drivability of a higher flywheel mass.

The trans was listed as a 4-port so most likely it has more to do with the engine. I'm assuming since I haven't heard anyone blow one of these 5-speeds up yet it should be able to handle the high rpm.

they also used it on the later 6-port engines similar to the automatic models with a 7500 rpm limit and a blank plug in the UIM VDI valve position.

It’s essentially the same as the FD3 trans with improved synchronizers

it’s a bit sturdier, can break fairly easy too imo, and has wider gearing gaps

for the full blown 6-port NA engine the 6-spd is a better choice imo, the 5-spd is a better choice for turbo with a wide, less peaky torque output, as has been well discussed over the years
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I bought the 5 speed with the intention that I plan to either rew swap or turbo when I get a fulltime job once covid rolls over.

Gearing wise I think If I had to stick with an 6port NA engine for a while, the S2 final drive could make up for the longer 5-speed ratios.

i'm confused, is the 5 speed stronger or weaker?

it’s an FD3 trans and a bit stronger, but in OE form still has to be given the kid glove treatment to not eventually shred teeth off of certain gears, it can still be broken fairly easy by hammering on it hard imo

I must of bought the last 5 speed jspec had left right after you...
it’s one of the final pieces to my REW swap puzzle. 4th was going out on the s1 6mt.

brand new rew block from Mazda. Just need the 7670. Turbo kit and Adaptronic ready to go.

These transmissions are a hot commodity right now it seems...

You know I bought it with the intent that I was getting a $900 paper weight, but I am rather excited to try this trans since it is disturbing how clean it is. I am prepping for a rew aswell, but building up as much of the rest of the car in the meantime upgrading towards anything that could be used with a rew setup. Currently fighting off New England rust, previous owner ripped off the caps under the rocker panels so they are pretty much ruined. Was hoping to find a clean low mileage shell, either that or completely restructure the pinch welds from wheel to wheel. Got some crazy ideas I plan to do to my car for the rew build. Gotta learn how to tune first. Been messing with small stuff in mazda edit already, fan temps, coil dwell, omp output, dtcs.

Can't try the trans until the racingbeat swaybars and new rx8perf motor mounts arrive (2 weekends out till everything is back together). Waiting to do these while I have the subframe out.

say wut; $900???

I thought this was a good deal for $320 USD picked up local, but MadMax on here deflated me, saying he paid even less


https://cimg5.ibsrv.net/gimg/www.rx8...7bdb43627.jpeg
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https://cimg6.ibsrv.net/gimg/www.rx8...a39f95dee.jpeg
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Well the trans was 550, but adding shipping was a killer for me since I live in the sticks. Somehow UPS freight also lost my address when it got to the hub in New Hampshire, so I had to go drive about an hour and pick it up myself or wait another week. I called 3 different times and they said everything was fine, tracking numbers said all my information was there. Ended up calling the actual site the tracking number said it was sitting at and they had no idea where to send the trans. Apparently UPS freight is terrible compared to normal UPS shipping.

Yeah I had to pay $350 shipping also.
Local pickup wasn’t an option since the car is in California, and I’m in Texas.

When I was looking Nengun was offering 5speeds for $80.....but for local pickup in japan

local pickup for me was DFW metroplex, just happened to see it for $500 shipped on an auction site, went there in person on Saturday afternoon. They were willing to let it go for $400 picked up. Just happened to have $320 cash and offered to go to the bank, but they were about to close. We hemmed and hawed some, then rather than take a chance on me not coming back, they accepted what cash I had. Haven’t looked in a while, but usually the sell around that same $500 shipped price. If you see one listed with an engine they’re usually willing to split it off separate if you ask. Kind of shocked is all. 😳

Capitalism at it’s finest. I just wasn’t willing to let another one slip from my hands and gamble on a junkyard 6mt.

If I end up having to rebuild this one, at least I’m starting with what I want.

Supposedly stronger. Mine is sitting in the garage waiting till I get a 5.10 to use it cause the spacing is wide from 2nd to 3rd. Naturally, 4th is 1:1.

Figure I give a follow up since I got my car back together with the new 5speed jdm trans ~60k miles. Using the stock S1 4.44 diff and tire size. Stock 6 port US clutch and flywheel

Compared to the stock 6 speed the gears feel more evenly distributed across the board with the 5 speed, but longer. 1st gear in the 5 speed being drawn out doesn't make it feel like glass. There doesn't seem to be any noticeable drops between gears of the 5 speed. The stock 6 speed always felt like 1st was too short, but gave 2nd all the acceleration leaving a bigger gap between 2nd and 3rd. Reverse was also notably much easier to get into with the 5 speed, unsure If I just happened to have 3 bad 6 speeds, but reverse was troublesome in each one.

The trans I have appears to only have synchro issues with the 2nd gear, everything else feels very clean. I'm contemplating getting a S2 diff for the more aggressive final drive, but this will most likely have to wait for spring. I'm sure I will end up rebuilding the trans at some point, sure hope it doesn't turn into a mess of finding parts.

thanks for reminding me, been meaning to ask about a parts list. Most parts should be the same as the FD3, except of course the newer multi-piece syncro rings. Since it was never offered in the USDM, accessing the parts listing for it is difficult. As best I could ever determine they never offered a paper service manual for it. I was able to find the service literature online, but it only details the differences with the FD3. Which the FD3 service manual is online.

In the distant future with a full time job, I will most likely be looking to do a rew build....and going to buy another rx8 for it. If I happen to find a good price on a jdm rew block with a trans I may pick it up and be able to compare the Rx8 6 speed and jdm 5 speed against the FD internals. I'll definitely document everything pulled apart when the time comes.

the more definitive thread on this is here

https://www.rx8club.com/series-i-maj...setups-225750/

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Does your 5-spd still have a legible label in the outer bell-housing and if so, what is the code indicated on it?
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No, the label has faded off. I did contact J-spec who I bought the 5 speed from about sourcing a rebuild kit. They are waiting to hear back from their guys in japan.