gmc 8.1L V8?

Question

Does anyone out there have a 2006 or 2007 Sierra 2500 HD 2WD w/ the 8.1L V8 and Allison Transmission? If so, what kind of gas mileage are you getting? I know the Allison transmission went from a 5 speed in 2006 to a 6 speed in 2007. Did it make a difference in fuel economy? I don't want the Duramax because it is such an expensive option. It puts my new truck budget over it's limit, but I can slip just under budget w/ the 8.1L V8. Educated opinions will be appreciated. Thx.

Answer 1

I had a customer tell me he gets around 16 on the highway between NY and FL, a bit less when he's towing (not as much less as you'd probably think). But gas mileage is HIGHLY subjective, and absolutely dependent on where you are, what you're doing and your driving style.

I do agree that resale will be a nightmare if gas prices stay high. Plus, the 8.1 is apparently not available in the new body style.

Answer 2

if you really dont want the diesel, the id go with the 6.0L, which when outfitted with the proper gear ratios and performance enhancers can be one of the best power-fuel economy examples out there. The only thing better than the 6.0 is the duramax diesel. it may cost a little more in the short term, but in the long run it will cast you considerably less. The diesel gets about 20 miles pergallon, has nearly unlimited torque and horse power, and is nearly indestructable. I have heard of duramaxs oulasting the frame of the truck. Im not trying to break your bank but if you want great power and great fuel economy then you should consider a deisel.

Answer 3

Expect to get about 10 mpg. And its noisy as hell. Been selling Chevy's for 5 years. Almost nobody buys the 8.1. They only last about 100-150k miles and you only need that kind of power if you are towing a ton of weight. Otherwise it doesnt feel fast in the truck, just loud. I'd go for the 2500HD with the 6.0, resale is much higher and youll average about 12-14 mpg.

Answer 4

yea, i wouldn't listen to kmank man. the 6.0 is a good engine, but it will get upwards of 11-15 mpg in the city. a lot better on the highway. the 8.1 is only noisy if you chop off the exhaust or do some intake mods. it's a great motor, it's actually a bored(or maybe stroked) 454, so it's been time tested. expect about 10 mpg in the city from that engine, but it's got tons of power.