DOHC to SOHC trans swap

Looking to save some gas on longer trips, and needing a new clutch
anyway, I want to switch my '94 SL2 to the SOHC 5spd. Is it only the
91-94 transmissions that will bolt up? I have been given conflicting
advice from someone selling a 2nd gen SOHC tranny and a mechanic.
What's the real deal? Can anyone comment on MPG improvements for the
twin cam engine and SOHC transmission? Or should i just put in a new
clutch and forget the whole thing ?

Thanks - Timothy

 

The savings is neglegable. You might squeak out a hundred dollars a year
on saved gas but what do you loose? Horsepower and time & money invested
in it. Inflate your tires to the max sidewall rating if you want to
improve gas mileage. If the side wall says 35psi, fill to 35psi, if it
says 44psi, then fill to 44psi. Keeping you car tuned up and in working
order, keeping your tires inflated, and removing dead weight in the
trunk are the biggest fuel savers of all.

 

Clutch replacement / trans swap instructions:
http://www.cristhomas.com/cars/Clutch/ClutchHowTo.html

The Ultimate Saturn Swap guide:
http://www.saturnspot.com/showthread.php?t=15149 (has interchangeability
info)

In my experience (I have a '97 trans in my '94, and a '93 trans in my '92),
both SOHC and DOHC S-Series manual transmissions from '92 and up should be
interchangeable between all years (although the clutch, flywheel, and clutch
hydraulics are not interchangeable between all years - ask your Saturn
dealer to check their parts book for details or check the swap guide above).
There are slight differences in gearing between years, and a slightly larger
difference in gearing between SOHC & DOHC.

Swapping the entire trans sounds like a lot of work and expense, and may not
be necessary in light of your goal. I've heard that you can put 5th gear
from a SOHC trans into a DOHC trans in order to improve your mileage. You
may even be able to do it through the wheelwell, without removing the trans
from the car. You may want to do some investigating. A good place to start
is to search the S-Series forums on http://www.saturnfans.com .

Lane [ lane (at) evilplastic.com ]