Chevrolet 8.1 Vortec advice
 

I have a 2007 3/4 ton pick-up with the 8.1, its 2wd with 4.10 rear and the 6 speed Allison trans, does any one have any advice on improving towing mileage? I tow a 26 ft Gold Rush with a 2700 lb car and race day stuff, it currently has a Voliant cold air and a Black Bear tune through EFI Live. Any additional input is appreciated.

Re: Chevrolet 8.1 Vortec advice
 

What does it get for mileage now towing?

Re: Chevrolet 8.1 Vortec advice
 

Towing 6 after tune 7.3
Driving 9 after tune 12-13
Am I expecting to much?

Re: Chevrolet 8.1 Vortec advice
 

That's some pretty poor fuel mileage. My Freightliner toterhome gets better towing mileage than that truck.

I have had 4 different dually pick up's all had diesel engines and all got about the same fuel mileage. 9-10 towing and 15-17 around town. My toter gets about 8-8.5 towing and 10 empty. Same trailer on all the trucks loaded 40 ft gooseneck 14K lbs.
That being said gas is cheaper per gallon than diesel fuel so that offsets the cost a bit. How much long distance towing do you do and what speed do you run when towing?

Re: Chevrolet 8.1 Vortec advice
 

I had a '96 GMC 2500 HD 4x4 that I used for towing for years.

7.4 with auto overdrive and a 3.73 rear

It got about 10 MPG or less towing a 26' trailer with a Lance Camper loaded in the bed. I can't recall exact figures but I know that's close. I changed a few things but it made very little difference mileage or power wise.

My buddy had an 8.1 pickup and mileage was poor and lower than my 7.4 pickup for sure...

My '96 Pickup never got better than 15mpg on the highway and not towing anything....and that was driving 55-60 ....

I have a Class C E450 Ford motorhome with a V10 it gets about 7MPG towing the same trailer...

My Duramax pickup gets 12-13 back and forth to work.....10-11 towing with the camper and trailer out back when I used that truck...

The 8.1 has always had a reputation for poor fuel mileage similar to a Ford 460.....

Re: Chevrolet 8.1 Vortec advice
 

Most trips are less than 250 miles, mainly in the Carolinas. Mixture of two lane roads at 50 to 55 miles per hour and highway/interstate 60 to 70 pending on traffic. At speeds of 50 to 65 it shifts a good bit but at 65 and quicker it smooths out. Before the tune any kind of grade change it would drop back to 4th, its not as bad now will drop to 5th and pull on.

Re: Chevrolet 8.1 Vortec advice
 

We tow with a 02 Suburban 3/4 ton 4l85E trans, 4.1 gears 265/65 /16 tires. We got about 7mpg. This last year got rid of the cats put in a balance tube up front and a flowmaster cat back system on. From there we went on a wheel dyno for the tuneup, picked up 50 lb of toque and 40 hp at 2300 rpm. It has great power towing but now gets 7mpg. We will be doing a intake mod [google 8.1 mod] have the intake done just need to install it. I just do not think these almost 500 ci motors are made to get mileage, but they pull great and are cheaper to maintain than a diesel. Tom

Re: Chevrolet 8.1 Vortec advice
 

I had a 2002 2500HD 2wd with Allison tranny and 8.1 vortec. I got right around 10mpg towing about 8K #s. The tranny temp would go up a little going up hills but nothing too bad. When conditions allowed, I ran around 75 mph with the trailer with no issues.

Re: Chevrolet 8.1 Vortec advice
 

Tom, thanks for the reply; the one thing I can say for this thing is it does not lack for any power! If it was weak and got poor mileage then that would lead me to believe something was wrong and point me in some direction for action. I believe you are correct in the fact that its just big and its going to get what it gets. A lot of gas can be bought for the cost of another truck. Might just add an auxiliary tank to avoid so many fuel stops! Bob, was your pick-up stock and did it hunt between gears when towing at highway speed?

Re: Chevrolet 8.1 Vortec advice
 

What engine rpm is it running at what mph?