Hi. I've have my RX8 for over a year now and after having driven my friends manuals during that time too I've decided its time to get a manual car. I thought It would be a great project and since the RX8 was my first car I wanted to keep it as my daily. Ive been reading forums about this type of conversions online but the parts compatibility is non specific. I own a 2009 RX8 Grand touring which is a series 2 and there's a lot of Rx8s in the scrapyard by my house but they're series 1s. I was wondering if the transmissions between the s1 and the s2 were interchangeable. Im almost at rebuild mileage so ill be replacing the engine with the manual spec one. Again I want to keep this car because it was my first car and I dont want 2 cars because im a student and wont have the money to pay for them both so please keep the go buy another car or just sell it and buy a manual comments out of this thread. Thanks.

 

i believe you can use a s1 trans. i have a a bit of drive train parts from a s1 mt. if your close ill sell them cheap but dont want to ship. im in pa

 

It will be cheaper and easier to sell your Rx8 and buy a manual transmission one. Plus if you are in California, or any state that does inspections, you will fail due to the check engine light from all the error codes your car will have because it wont detect the automatic transmission, assuming it will run at all. It might force "limp mode" and the only way to fix that would be to install the computer from a manual transmission series 2. Then the VIN wont match between the computer and the car, and you definitely wont be passing inspections anywhere.

 

As a general rule of thumb, don't attempt an AT to MT swap on a car made after 2000. It's a big pain unless you are a pro, and even for pros, this is not worth the hassle as Xero mentioned.

Technically you can install an S2 trans on an S1 with some minor wiring changes, so it should work the other way around. However, most people use the S2 trans because S1 trans has a pretty fragile 4th gear.

And MT and AT S2 differences go beyond that. MT S2 has an extra oil cooler, the carbon fiber composite driveshaft, a different differential ratio(4.778 for MT, 4.300 for AT), a different tower brace, etc. It's actually quite a bit of work to get your AT to be a legitimate MT.

Even if you surmount the mechanical differences, somehow, electrical wiring is gonna be ten times worse.

TL; DR: Sell your AT and get an MT.

 

^^ * 10000

I've done manual conversions on older cars. They all sucked. Converting an RX8 will suck even more because of the increased reliance on computers. Just sell your automatic while it's still in good shape and get a good condition manual. It's just a car, it feels nothing.

There is no such thing as 'rebuild mileage'.

 

As someone who survived this kind of project (on a Series 1) it CAN be done. Rotary Resurrection has a very useful guide, but that was all Series 1. Things i had to procure:

1. transmission
2. clutch pedal
3. upper and lower shift boots
4. Manual trans brake master cylinder reservior (supplies clutch fluid)
5. Clutch lines
6. steering wheel (not required but nice to have)
7. instrument cluster (not required but the shift warning buzzer is based on the tach, so if you want to enjoy the higher revs without being warned, change the cluster! Also no more gear indicators)
8. Manual trans ECU (from same car)
9. Manual trans ABS controller (from same car)
10. Manual trans immobilizer module (from same car)
11. Manual trans driveshaft (not required but nice to have, automatic one was steel, manual was CF)
12. Rear differential

It is a HUGE pain to do. It can be done, it does drive (not in limp mode) and it is possible to make all the CELs / warnings go away, but it takes a lot of knowledge and a lot of patience. i have never gotten hassled about the donor ECU VIN not matching the chassis, i just tell them it got a new engine and ECU (which is technically true). The wiring is pretty straightforward, and RR's guide makes it very easy. I dont have a clutch interlock on the starter, but since I eventually want Remote Start, that didnt bother me.

Ill try and respond if I can answer specific questions

 

Getting a donor car might be the best way to go to make sure you get all the parts you need. An S2 with a bad engine or possibly a wrecked one, but they will be harder to find than S1s.

 

All of this is again irrelivant if he lives somewhere, like California, that does emissions inspections and the vin in the pcm MUST match the vin of the car.