I just calculated my gas mileage driving from Houghton to Traverse City a couple weeks ago, 208 miles using 6.892 gallons comes out to 30 miles per gallon! That's by far the best I've ever gotten from this engine, and the car was loaded down with heavy stuff, too, averaging 70 mph over the course of the trip. I usually get 23 mpg around town. The auto stills sucks for gas mileage, though.

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1984 Fiero SE

What engine? If that's with a 3 speed auto - that's pretty impressive.

Best I've ever gotten in my Formula is 33 mpg - all highway cruising with a 5-speed.
On a recent road trip in my 2000 TA, I got 28 mpg. Again, 6-speed manual - makes a huge difference in mileage over an automatic.

I wonder how a Duke with a 4t40 or similar 4-speed auto would do?

I get 40+MPG all the time, 86 Duke with a 5spd. I have wondered about the 4T60 on the duke myself. I hate shifting gears.
Joe Crawford
Texas

Yep......the auto sucks the mileage out of both the V-6 and the 4 banger. I had an '87 auto. coupe that got 37 MPG on the highway......I know if it were a 5-speed it would have gotten 40 MPG all day long.

At this point, anything over 30 MPG is good, so way to go!


As for a 4t60 with a Duke.......I would think it would get well over 40 MPG, but who knows? I know that a stock 2.8 with a 4t60 gets mid 30's, so low to mid 40's with a Duke is plausible.

[This message has been edited by mrfiero (edited 05-17-2008).]

I was thinking of replacing my TH125 in my 3.4 pushrod Formula with a 4T60. Does anyone have that setup? If so, what kind of mileage does it get? The best my 3.4 has ever gotten is 25mpg. And that was my wife driving it to work and back (mostly highway).

makes me seriously miss the duke..

I have also wondered about the Duke's power band when hooked to a 4T60. Its a little animic as it is

I get about 31 MPG mixed driving with a Duke-Auto

What can I expect out of my '87 GT stock w/ 5-spd??

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So now you'd better stop and rebuild all your ruins,
For peace and trust can win the day despite of all your losing

quote Originally posted by FIER086: What can I expect out of my '87 GT stock w/ 5-spd??

A reliable average, on the highway, is around 28.

<top Black 86 2M4 w/ T125 32-34 hwy mpg

<btm Red 87 Coupe 3800 Series 1 N/A with 4t60 33.5 hwy mpg

[This message has been edited by 30+mpg (edited 05-19-2008).]

quote Originally posted by josef644: I get 40+MPG all the time, 86 Duke with a 5spd. I have wondered about the 4T60 on the duke myself. I hate shifting gears. Joe Crawford Texas

If you get a transmission controller you could mate up a 4T60e... I just happen to have one for sale in the mall.

Man those MPG numbers are gorgeous. Now I really need to get my Duke running. 19MPG in the Camaro is starting to hurt.