s10 (s15) economy

[gasssaver87]

hi all, i just traded a couple of three wheelers for an 83 gmc s15. the engine (2.8 liter) is bad, but it has a 4 speed and 3.08 gears in the rear.

it is an extremely ugly truck, but that doesn't bother me none.

the previous owner couldn't tell me exact mpg numbers but was pretty sure it was around 18-20.

i was thinking that i could put another engine in, new fluids in it, do a grill block, electric fan (its current fan is solid, not even a clutch) an alignment, recurving the ignition timing while adding a hotter coil, and replacing the rochester POS with a weber Progressive that i have, dual exhaust and maybe eventually an RV cam it it seems like it would be worth it

I would much rather have a 4.3, but i would have to put bearings into an s10 t5 that i have, but i would probably need a different clutch/flywheel and a bellhousing as well.

does anybody know what these usually get for mpg? any guesses as to what i could get it up to?

[rvanengen]

Originally Posted by gasssaver87

hi all, i just traded a couple of three wheelers for an 83 gmc s15. the engine (2.8 liter) is bad, but it has a 4 speed and 3.08 gears in the rear.

it is an extremely ugly truck, but that doesn't bother me none.

the previous owner couldn't tell me exact mpg numbers but was pretty sure it was around 18-20.

i was thinking that i could put another engine in, new fluids in it, do a grill block, electric fan (its current fan is solid, not even a clutch) an alignment, recurving the ignition timing while adding a hotter coil, and replacing the rochester POS with a weber Progressive that i have, dual exhaust and maybe eventually an RV cam it it seems like it would be worth it

I would much rather have a 4.3, but i would have to put bearings into an s10 t5 that i have, but i would probably need a different clutch/flywheel and a bellhousing as well.

does anybody know what these usually get for mpg? any guesses as to what i could get it up to?

Way back when (late 80's), my father had an 84 S-10 Blazer 2.8 5-speed that seemed to be getting about 22 on the highway.

[caprice]

ouch Bite the bullet Go for an "iron duke" 2.5 4 cylender. very common in other cars besides the s10 (translation: easy to find at the salvage yard). Plus "no one likes them" because it has the "weaker" engine. (translation: costs less to buy.) Save weight and friction, install a S10 manual steering box, if not equiped. You will apreciate narrower front tires though!

With a 5 speed and TBI:
24 City
30 Highway

Better milage than my Daewoo Leganza! haha How sad is that?

I am starting to wish I put a used iron duke in my caprice. The car weighs the same as a s10, and more areo dynamic than a truck. It would would compliment a 6 speed transmission very nice! That definatly would be "out of the box" a 30+ MPG from a oversized car! I never need the power from my 350 anyway.

[Bill in Houston]

I was thinking Iron Duke too. But it sounds like maybe he wants a little more power.

The Caprice came with a V6 in the '80s, I think. Maybe one of those would be an easy swap?

[BumblingB]

There's always the possibility of a "sloped" bed cover. I keep hearing people rave on about how it netted them huge increase on HWY mpg.

[jdham137]

I'm working on a belly pan for my and might have it done in a few days. I'll post pics when it's down. I think, and Phil Knox does too, that the belly pan will net better results than a sloped cover. A truck's underside is a aerodynamic engineer's nightmare. There's no attempt to smooth anything. The flatest surface is the gas tank and the rear bumper and frame members looks look as though they probably act like a drag chute for any airflow that makes it that far back. It's a mess and I can't wait to see what this does for my highway mileage.

John David

[rh77]

Originally Posted by caprice

ouch Bite the bullet Go for an "iron duke" 2.5 4 cylender. very common in other cars besides the s10 (translation: easy to find at the salvage yard).

Is that the one they put in the Celebrity? If so the Auto-trans is real bugger to repair...

RH77

[lovemysan]

I put a good many miles on a 93 s10. 2.8l 5spd It averaged around 24-26mpg hauling tools and misc stuff. Mostly rural small town driving. Its a tough little motor. My favorite of all s10 powerplants. At 200k with the original timing chain and something ticking in the motor it still got a steady 24mpg driven by my 19yr old brother.

[Bill in Houston]

Originally Posted by rh77

Is that the one they put in the Celebrity? If so the Auto-trans is real bugger to repair...

RH77

Probably the same one but thankfully the S-10 would be a rear drive. I think that the iron duke was their main (maybe only) 4 cylinder until the Quad4 replaced it.

[Maillemann]

I had an '85 GMC S-15 for many years, and with the 2.8L 2bbl engine I averaged just under 20 MPG almost invariably. Lots of city, would be around 18-19, lots of highway, 20-21. Most I ever got out of it was just shy of 24, but this was with an auto trans and 4WD. I'll echo the comment on the engine's reliability - it was pretty bulletproof. Very few issues right up to the 280,000 mile mark when I gave it away.