aw11rally and myself co-own a Mk1 MR2 tarmac rally car.
Last year was our first season of competition and we were plagued with broken driver's side driveshafts and, as a knock on effect, bellhousings.
We had major problems selecting gears when the car was being driven at 100%.
It didn't want to go into 2nd gear on upshifts and was also obstructive on downshifts from 3rd to 2nd and 2nd to 1st.
The gear selection problem cost us lots of time on stages.
It also became obvious after a few events that the gearing was too long.
3.722 seems to be the lowest Toyota final drive available for the C50/C52 transmission.
For these reasons we started looking at alternative transmissions and realised that now Lotus are fitting the Toyota 2ZZ-GE engine to the Elise
& Exige, we might be able to use the associated 6 speed C64 transmission and the stronger Lotus driveshafts on our car.
The C64 is a closer ratio box and has a 4.529 final drive ratio.
We have fitted the C64 with a Corolla C52 bellhousing to match up with the bolt pattern on the engine block
(we'd broken all the spare MR2 bellhousings we had).
The driveshafts are hybridised Exige.
Lotus inner CVs
& the Lotus driveshafts have been turned down and re-splined on their outer ends to fit the AW11 outer CVs.
The driveshafts are standard
(Lotus) length.
The AP racing concentric clutch slave cylinder was necessary because the standard clutch fork fouled on the Lotus gear selectors.
The C64 bolts up to all the standard MR2 gearbox mounts, which is nice.
The gear selector is Exige, cut down
& with new mounts to fit in the standard MR2 mounting holes.
The gear lever has been shortened, as in the Exige/Elise the selector bolts to the floor.
In the MR2 the standard length gearstick ends up almost level with the top of the steering wheel.
We also removed the Reverse gear lockout mechanism as it was preventing selection of 1st
& 2nd.
This won't be a problem, as with the shortened gearstick you have to be He-Man to push the lever over against the spring to select reverse.
We had the car out for it's first test run Saturday teatime and I don't think either of us have stopped grinning yet!
The 4AGE in our car is on twin Weber 45 DCOEs and it only starts to make power over 3000rpm, then tails off around 7500rpm.
With the six speed box
& shorter final drive it comes on the cams much quicker, doesn't bog down and now goes like it should have done all along.
The gearshift is nice and smooth, with a very short throw.
Quick calculation gives a total cost of between
£2100
-
£2200, but the Quaife ATB was
£630 and the AP clutch slave
£248 of that.
If anyone suggests that a Saab 900 concentric clutch slave will fit, it doesn't.
We tried that.
