8.1 GM mileage
 

What kind of mileage are you guys seeing with the 8.1's? I'm looking at a 4x4 2500 Burb and am just curious.

Re: 8.1 GM mileage
 

Jason, Have a 2001 with the 8.1 and a 4:10 gear. On a pure highway shot - not towing - at best have seen about 13 mph. Have not checked it towing because I don't want to know! :evilb: Wrink

Re: 8.1 GM mileage
 

I saw 10-11 mpg
8 towing 12K

w/ a Wester's ECM and a heavy foot. This truck would rock!

Re: 8.1 GM mileage
 

10-12 normal driving...

and the good news.. a whole 5 MPG towing roughly 12,000lbs... :eek:

Re: 8.1 GM mileage
 

Have a 2001 for sale fully loaded and then some!! yukon xl

Re: 8.1 GM mileage
 

:eek:

Re: 8.1 GM mileage
 

2001 gmc dually,
13 to 14, empty
8 to 10 towing 38 ft donzi

Re: 8.1 GM mileage
 

2002 8.1 w/ 4spd Auto 4L85E in 2500 Avalanche (same as Sub 2500).
Lots of bolt on goodies.

11 daily driving.
6.5-8 towing 12K lbs, depending on flat Interstate or hills/mountains.

Re: 8.1 GM mileage
 

Thats about what my V-10 gets.

Re: 8.1 GM mileage
 

Oh yeah, 4.10 gears. I have 17" wheels and 265/70/17 E tires on it now. The Suburban will tow MUCH better with these changes:

Wider wheel/tire combo. (Go to an 8 or 9 inch wide wheel.)
Add rear airbags to help the rear suspension. (Do a search on this on OSO, lots of info.)
2" Rear wheel spacers. (Will spread out the rear wheel track to match the front wider stance, and also help towing stability.)

Everything IU have done to my Avalanche 2500, can be done to the Suburban 2500. (Exact same frame/running gear.) Check this thread for more info on what I have done:
http://www.offshoreonly.com/forums/s...d.php?t=109513

Re: 8.1 GM mileage
 

Yea, that is what I was expecting to see (10-12 mpg). Looks like I'll be buying a Denali XL with the 6.0 instead.

Re: 8.1 GM mileage
 

You won't see much better with the Denali.
First, its AWD (all the time) which will eat 1-2 mpg over a 4x4 with 99% of driving as 2WD mode.
Second, the power-band of the 6.0L is REALLY high. You have to get that thing to 3500 rpm to pass someone, and it really needs to tac up to get s load moving.
My advice is to get the grunt of the 8.1L. I test drove a Sierra Denali with the @340HP version of the 6.0L that they put in the Escalade/Yukon/Denali etc. I liked the truck, but as I said, it felt like I was driving a 5.3L.

Re: 8.1 GM mileage
 

I just got my 2005 6 liter2500 hd and it gets around 16 mpg, has a tow rating of 9500 pounds, 6 bolt main with aluminum heads, i love it!!!!!!! Needs bigger rims and tires, but winter is almost here, maybe next year!!!!!!!! :drink:

Re: 8.1 GM mileage
 

What are you towing? Don't get a smaller truck package if you need to move a big load, as you will be sorry.

My 8.1 with 4.10 gears gets 12-14 day to day and 7-10 towing 12K LBS.

Re: 8.1 GM mileage
 

Haul 10,500 w/ a 6.0L 3.73 Burb. GET THE 8.1L!!!!!! Hell, if you decide you don't like it, I'll pay to switch engines with you. Unless your towing 5K or less, the extra 1 MPG lost is worth every penny in towing capacity.

BTW: My annual average mileage is around 12 on the computer. Best highway only trip was less than 14.

Re: 8.1 GM mileage
 

I may not even be towing but 2-3 times a year if I keep my boat. My boat only weights 9500 or so on the trailer, full fuel so the Denali will tow it. The Denali gets 17 hwy if I rember right, 12 town. I agree you can't beat a big block for towing but the price of gas and the miles I drive a day, I just can't get warmed up to the 8.1.

Re: 8.1 GM mileage
 

driving one of these for a week will make you all warm inside. :D

I'll never drive a gas truck again.
The DMax is very powerful and user friendly (quiet/smooth).
The wife will never know the difference.


plowed and towed both.
daily driver also

Re: 8.1 GM mileage
 

I want a dmax but it is not available in a Suburban, till 07 and I need a vehicle p.d.q.

Re: 8.1 GM mileage
 

If a Burb is available w/ a Duramax in 07 then my 03 6.0 will be the first one for sale next fall!!!!!
I hope your right, but I won't believe it til I see it.
Don't get the Denali if it's all wheel drive. A few years ago we had a grand cherokee all wheel drive and it sucked gas like crazy.

Re: 8.1 GM mileage
 

Avalanche- 2500 4x4 4.10

All around mileage is 11.5-12

Hwy 13-14

Towing 10 ( horse trailer- 4500 lbs)
Towing 8 ( 30 ft twin boat- friends- 9000 lbs)

5 mpg- no way

Wannabe

Re: 8.1 GM mileage
 

I custom ordered a HD2500 Sierra SLT heavy spring and tow pkg, loaded and then some, 6.0L w4.10 gears. I like it for what I'm towing 242 Formula. If I had it to do over...((( GET THE 8.1L ))) :D
The difference in mileage is minimal but the difference in power is HUGE.

Re: 8.1 GM mileage
 

EXACTLY !!!

Re: 8.1 GM mileage
 

the dmax is great do not buy one if you are not going to put 20K per year on

i have pulled my formula 353 with all combo's. the 353 on trailer weighs 11 -12 K. the 6.0 worked really hard to get it dun, 7 - 8 mpg.
8.1 purred like a lion 9 mpg and could use cruise (could not on 6.0)

duramax loved the load.

the denali will move the load but not like it over long distance.

Re: 8.1 GM mileage
 

these are my experiences also towing a 353.
12K plus on an Eagle with fuel
the 8.1 makes much more torque where it counts than the old BB

the DMax just doesn't sweat it!

Re: 8.1 GM mileage
 

wondering how you guys got 8.1 trucks with 4.10 gears since they were only ever available with 3.73's I have a 2002 2500 HD and tried to order it with 4.10 's and they aren't available that way .what does your gear code say on the tag in the glove box? starts with a G

Re: 8.1 GM mileage
 

GT4 is 3.73.
GT5 is 4.10.

The Avalanche has a factory option for which set you want.

Re: 8.1 GM mileage
 

I have a 2001 Chevy 2500 HD with 8.1 and I agree with everybody else. I get about 10-12 normal around town. I have gotten close to 16 on the highway not towing of course.

Re: 8.1 GM mileage
 

I have a 2004 regular cab 2500HD 8.1 Allison and I looked at the code GT5 and have the window sticker that says 4.10

Cordell

Re: 8.1 GM mileage
 

the 8.1 was available with both ratios from the get go.

you CANNOT get a DMax with 4.10's

4.10 standard with the 6.0 to try and make up for torque it doesn't have.

perhaps you were taking the word of a less than knowledgable dealer?

Re: 8.1 GM mileage
 

Does anyone know how the 07 Suburban will look like? Or is there a link to a site.