[Christ]

Originally Posted by darcane

I had basically the same engine in... a '94 Corvette. I had a huge range in mileage depending on how I drove it: 10-29mpg. If I was being good, it wasn't hard to stay in the 25-29 range though. Mine was a manual.

Besides the tranny, the big differences are:

• Weight. Maybe you can try to remove some mass.
• Aerodynamics. Some of the aero tricks may help here, but that fact is, it's a big car.
• Gearing. 0.5:1 overdrive in the manual... But the auto was still geared higher than your car with 2.73:1 differentials. It may be worth switching over.

Switching to a manual shift probably won't help enough to matter. The big problem with the auto is the inefficiency of the tranny design. You need to use power to operate the pump and you'll always have the torque converter to deal with.

-Mike

The big problem with the auto is having to push fluid around. That's the largest inefficiency with automagic transmissions. They're still directly connected from input to output by gears and clutches, just like a manual. The fluid movement is the demon there, and for obvious reasons, you can't overcome it. The difference isn't THAT dramatic in efficiencies between manuals and automatics of this time period, though. It's only a couple percent torque loss, mostly due to the locking torque convertor, which locks at a 1:1 ratio input to output. From that point on, there are small frictional losses, some fluid pumping, and then the output.

The torque convertor losses are able to be eliminated once you've left 1st gear, since you can manually lock the TC. If you're not using alot of torque to accelerate, you can safely accelerate under TC lock without causing it to let loose.