the hp/tq/gas mileage difference between 2.8/3.1

[no_doz]

ive been thinking about it a lot & my buddy had a 92 2.8 5 speed 2wd gmc sonoma that got like 28mpg highway & weighed like 2400lbs, but ive had a couple 90-92 3.1 luminas that got 29 or 30 highway & good mileage in town, so i got to thinking. the 2.8 has a -very- short stroke, i figure this means its faster revving if built right? also with most engines, .3l is a pretty good difference in size (not immense, but enough to drastically change gas mileage/power)-but the 3.1 & 2.8's from that same era have virtually the same hp (if you look at the 2.8's in fieros & such) the hp is only like 10 less, but even in a much lighter vehicle it gets worse gas mileage-is because of the lack of torque or the short stroke making it fire more or ? if a 3400 block was used with a 2.8 crank to make a short stroke 3.1, would it be a fast reving well breathing beast, or would it just be an effective way of denutting the 3400 a bit?

[carbon]

The 2.8(or 2.5 4 cyl) in a Fiero with a 5spd manual tranny gets mid-30s MPG on the highway... the Fiero milage got hosed with a TH125C 3Spd 3.33FDR automatic. It has nothing to do with a lack of torque. The lack of an overdrive gear and a high gear ratio of 1.0 kills the fuel economy with the automatic. Can you say 2500RPM to go 55MPH?

The F-body 3.1 got 20Ft-lbs more torque but the same horsepower rating as the 2.8... thats what happens when you only increase the stroke. When they increased the bore to make the 3.4 they got a 20HP boost.

The Sonoma only got 28MPG with a 5 spd becuase it was an aerodynamic brick on the highway.