The Automatic to 5-Speed Conversion
Difficulty: Hard
Time: A lot
Discussion:
This car has been an automatic for too long… I’m tired of being beaten off the line by Civics! Most of my family thought I was crazy for doing this. I took a perfectly good working transmission and had it replaced. Actually, sometimes I agree with them that this was stupid but not for the same reasons… I could have bought a used RX-7 with a 5-speed for almost the same amount of money that I’ve spent on this conversion! $1450 might not buy me a Turbo II, but it could buy a high mileage non-turbo and I’d have two cars!
So why do it? Loyalty would be my number one reason! This car has been so good to me in the last 8 years that I could never part with it just because of the transmission. Plus I’ve also spent a lot of money (And time!) in parts for this car and I could never sell it for any amount even close to what the car is worth!
That was my problem. Live with the auto, not put any more money in the car, and let it die. Or get a rebuilt 5-speed installed and continue maintaining my current love…
I decided to swap them, but my next problem was that I didn’t feel capable of doing the job myself. I don’t have the tools, the shop space, or the experience. So I shopped around and got quotes from local shops and not so local shops… They ranged from $1200 for a used non-rebuilt swap, to $2500 for a completely rebuilt 5 speed with installation…
I finally selected K&D Rotary in Allentown, PA to perform the work. It’s a small shop that is specialized in working on rotary’s. The shop owner Dave, has been working on rotary’s for over 17 years and he has a passion for RX-7's similar to mine. He and I talked about what to put in the car: I though a Turbo II transmission would be my best bet because its stronger and would last longer. Dave however thought that since I was keeping the car a non-turbo that I should install an 85 GSL-SE 5-speed because the first 3 gears are lower and would provide better acceleration. I liked the sound of that! I was concerned about the 85 RX-7 transmission fitting in my car. But actually we didn't use the case from the 85 tranny, just the gears from the inside. The rest of the transmission came from a 87 NA.
He went to work, found the transmission and rebuilt it. I dropped the car off at his shop on a Saturday and it took about two weeks to get the car back. By the way, you should see some of the Awesome 3rd gens that he has in his shop!
RESULTS?
First off, let me just say that I learned a lot from this project!!! When I first got the car back I wasn't quite sure what to expect. I've driven my friends 5-speed before and I was real curious to see how my engine held up after running 125,000 miles while attached to that automatic... But as soon as I got in that car and felt the acceleration of first gear, I knew that I had made the right decision!
I never realized what a dog that auto really was... The car revs faster, smoother, and I think it sounds better too! I lost about 125-150 pounds of dead weight with the new 5-speed and this thing shifts great! (Thanks Dave!) And my friends 7? Well I have fun with him now because I blow him away off the line, every time!
THE FINAL WORD:
I started by saying that I've learned a lot from this operation. I said that because there were a lot of things I had to do to the car after I got the 5-speed in to make it perfect:
1) THIS IS THE BIG ONE: The 5-speed mounts are different from the auto!!! Everyone that I talked to about performing this swap said the mounts were the same but they aren't! The automatic is longer and the mount is about 5" back from where the manual mounts go. To fix the problem I had to cut mounts from a dead junkyard "7" and weld them into mine. This fixed the mounting problem but the cross member that was installed with my used transmission was worn out and the shifter jumped up and down like a rabbit. I ended up purchasing a NEW cross-member from Mazdatrix. This fixed that problem immediately.
2) The Cruise Control did not work after the operation. The components are the same for the manual and automatic, but the wiring to the cruise CPU was different. Dave and I had to cut 2 wires that came from the cruise computer under the dash. It took a couple hours of scratching our heads to figure out what was wrong... If you need to know the wires to cut, Email me!
3) I switched the EGI computer with one from a 5-speed, but I didn't have to. I got my donor EGI from an 86 GXL 5-speed and the part number was the same! So now I have an extra EGI computer... Maybe I'll send it out to get reprogrammed...
4) Drive shafts... The automatic shaft is shorter than a 5 speed. You will need a different drive shaft. Also note that some RX-7's have a Limited Slip Differential (LSD). The drive shafts are different from a LSD car and a non-LSD car. So make sure you know what you have in the rear!
5) The rest of the operation was "plug and play"! All the holes and mounts are already there, you just have to have the parts to transfer everything over... You need the pedals, master cylinder, slave cylinder, flywheel, all the plumbing, and a couple days.
6) The speedometer cable will screw right into the 5-speed. The cable is a little longer on the auto because the auto was longer, so you have some extra slack in the engine compartment. No big deal. As for calibration? The speedometer gear in the 5-speed is the same as the automatic gear, so calibration is not effected.
I think that covers the main points of the installation. You just have to figure out if you want a turbo transmission or a regular one. Definitely get a rebuilt transmission though! You'll never have a better opportunity to replace the syncro's... If you have any other questions, let me know!
OH!!! FLYWHEELS: When you get your flywheel, get a lightweight wheel WITHOUT the counterweight! The automatic already has a weight installed and you do not need the one on the 5-speed flywheel. This is also a perfect opportunity to purchase a light weight flywheel since you have to install one anyway! (Just remember to mention that you don't need the counterweight, and you'll save a lot of money when ordering!)