Home Forums Hunting & Shooting Hunter's Campfire Anyone Know How Squeeze an 8.1L Chev

There's a wealth of car knowledge here, so hopefully I'll be able to tap it a bit.

I got a 2002 GMC 3/4 ton with an Allison tranny and an 8.1 gasguzzler. I decided on a big gas engine, rather than a far more expensive Diesel, since this truck gets used 90% of the time hauling my trailer or 23' boat, and will at times have an 8.5' CO camper on it. I have other daily-drivers.

Are there any tricks that will increase the gas mileage without spending big buck$? I don't want to compromise its power much if at all. I love the truck and got it from a meticulous guy who serviced it often and kept a binder log book of everything he ever did to the truck, including adding a quart of oil. It has 120K on the clock.

I had one of these. Ran it up to 220,000 flawless miles. It got 10 MPG towing, empty, downhill with a tailwind. You’re feeding 496 cubic inches. Just relish in the reliability and don’t worry about the fuel economy, it is what it is.

Perhaps a Bully Dog.

Sell it.

I mean yeah if you’re worried about mileage but who really does that anymore besides liberals?

Possibly an entire exhaust .........….headers, dual cats, crossover, big mufflers, exhaust and tail pipes. And a tuner.

A block of 2x4 under the go pedal wouldn't hurt, either

I had the same truck in ‘03 when I graduated college. Tried every trick in the book when gas went sky high. Traded it for a 1/2 ton. Don’t think there are too many options unfortunately. But if it’s not your daily I’d just suck it up and have the power available when your ready to use it.

You can buy a lot of gas for what you'll spend trying to gain 1 or 2 mpg.

^^^Bonafide Fact^^^

Yup. Fact.

+1

Safari, contact Justin at Black Bear Tunes. He’ll shoot straight with you and I’m betting he can help without breaking the bank. Fine truck you’ve got there.

He knows how to wake up a 6.0 in a 2500hd.

The 8.1 is an expensive engine to work on.


Yes, the exhaust manifolds are garbage......but if you can find headers they are over 500 bucks.


There is not a whole hell of a lot to do with a tune either.


Mine has a big stoopid cam in it and it is now basically ruined........but a lot of fun in the passing lane.



Let it breathe a bit better and you might see some improvement.

Have one in a gmc Kodiak 6500 with a ZF 6sp. Manual trans. It pulls like a freight train.

Sell it, buy a dodge

Gas is $2.0X a gallon.

That's never an option for me.


I'm not obsessing about the gas consumption, since I drove a 1990 1 ton 4X4 big block Chevy for years.

I was just wondering if there were any tricks to improve the mileage. I love the truck, and I can live with it as-is just fine.

With lots of experience here it was something I thought I'd ask. Now I know.

Bruce, throw the camper on, hook up the trailer, get a hitch on the back of the trailer, hook the boat to that, throw the 12 foot rower on top of the trailer, load up yer gear and head north!
that thing will haul it all

Nothing I ever tried made enough difference to bother with.

I own 4 2500 Hemi rams. They get 10mpg, 12 if you really baby it