Corolla 3.722 FD C52 in 6G Celica ST, Any confirmed swaps? Results? Options

[dutchboy]

My clutch needs changed and I am considering replacing the manual transmission in my ST with one from a 7AFE corolla with the 3.722 final drive while I have the transmission out. Might even be able to get a straight trade if I can find someone that wants faster acceleration in their corolla.

Has anyone done this, and how did it affect the drive-ability around town and your fuel economy? It should improve highway mileage but wondering whether the car will require a lot more throttle (and gas) around town.

I really want to improve the MPG of the car, especially at freeway speeds. Looking at fueleconomy.gov though, the 7th gen Corollas didn't really have much better gas mileage, despite having the taller final drive ratio (all other gears are the same), weighing ~100lbs less than the 6th gen celica, and having .01 lower Coefficient of Drag (corolla has slightly higher frontal area, with CdA 6.58 vs celica CdA 6.54).

By the 97 model year, the 7g corolla and 6g celica 7AFEs were getting a couple more MPG than at introduction. Does anybody know where this came from? maybe the facelift bumper design on the celica, etc? Or was there a transmission/gearing/tuning change that someone knows the details of?

What about 5th gear swaps? I've done a lot of searching here and the only thing I saw that really talked about it was someone mentioning that 5th gear from a Toyota Levin GT-Z would work. If anyone can point me to a source for taller 5th gears that will work with an ST manual, it would be appreciated. It would be cheaper and easier, or could combine with the taller final drive for even lower cruising RPMs.

I know I could get some improvements with aeromods (grill blocking, rear wheel skirts, etc.), and I'll be working on those if I decide to keep the car, but I need to at least get the RPMs down in 5th gear, as my engine gets loud at/after 2800RPM (55MPH). Engine is at 3200RPM at `65MPH in fifth.


Thanks

[stephen_lee]

really no point unless you drive a siht ton of miles or can get the tranny cheap/free. cost of tranny > fuel savings.