You either have a tune for power, or mileage (can't really have the best of both worlds).

I am guessing since you have a sports car, that is supercharged you are more interested in power If you wanted mileage, you would've bought a Honda Civic instead.

 

You are right Tuned for power. The th400 is what really hurts the MPG.

 

I agree. I'm running a 388 LTx single turbo, TH350, 3.00 rear gear, and 26" tire. My speedo is accurate and the tune is good. The last time I checked mileage it got 14.x mpg on the highway.

Mike

 

I averaged 26mpg on a trip to VA, and got the same on the way back. It was about 20/80 city/highway with just a couple spirited take offs.

Stock long block. Bolt-ons, and a blower. 3.42 gears and a 6 speed.

 

I can almost get 20 MPG on highway only driving.

 

When it was near new and stock, I got 27 on the hwy and 25 average.


After many mods later...
A long drive from Phoenix to San Francisco netted me about 24 MPG while cruising at 75.

On any given tank of gas, I probably flex the throttle blades at least three or four 2-3rd gear romps and sometimes 4th gear romps. At the end, its been reduced to around 18-20 MPG during fill-ups.

 

For what I have, I'd say I'm pretty darn close to the best of both worlds. Can't see much more power or gas mileage out of mine.