8.1l Chevy

jcalvin

Looking at getting the chevy 8.1l (496) with the allison 5 speed tranny and was wondering if any of you have that set up. I can't afford to have two trucks at this time so this is going to be my daily driver. I know those trucks aren't known for good mileage but I would still like to know what it is so that I could plan for it.

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Cal


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Kgmz

We own 2 rigs with the 8.1.

Our 2001 Chevy Suburban with 8.1 and our 2001 Chevy 2500HD CC LB with 8.1 and Allison. Also own 2 trucks with Duramax's, a 2002 GMC 2500HD CC SB and a 2005 Chevy Kodiak 4500.

Mileage:
Suburban, 12 city and 15 hwy
2500HD with 8.1, 11-12 city, 14-15 hwy
2500HD with Duramax, 15-16 city, 17-19 hwy
Kodiak, 11-12 all the time

Towing the worst mileage we have had is 7.5 with the 8.1 2500HD towing a 25ft box trailer loaded at 10,000 lbs at a average speed of 80 mph from Portland to Wyoming. The 2500HD Duramax towed a similar, not as tall and lighter load trailer on the same trip following the 8.1 truck and averaged 10-11 mpg


Now the key to any decent mileage with the 8.1's is to keep your foot out of it. And it is hard to do with so much power. If I am foot happy with the 8.1 2500HD the milage drops down to 10 city and 13 hwy.




The Black 2001 Chevy with 8.1, and the 2002 GMC with Duramax, and the trailer I towed with the 8.1.

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angus242

With ANY truck, staying off the throttle is the best answer. However, if you spend some cash to make the engine run more efficiently, that will help. The down side is when you add efficiency, you are adding HP too. Now it makes it even harder to stay off the accelerator! But if you add a better intake setup, exhaust and perhaps a tuner...the truck will run more efficient which CAN translate to better MPG.

jcalvin

Well I just bought the truck and man it is a ball to drive. I'm going to go load up the skidsteer and haul it around just for the fun of it.

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Cal


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wolffhomerepair

KGMZ
What gear do you have in those with the 8.1?

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Kgmz

4.10's

ConstSvcs

I own a 2003, it's a great truck with plenty of power. Mine is a Sierra 4x4 with the extended cab. I have a Reading Space Cap +8 on the back. The cap weighs 900# empty. The big block & Allison combo great for towing. The only issues I have are:

1. Under a towing load the truck will use a quart of oil/ 1000 miles. This has be documented by GM and is accepted oil consumption for the motor (according to GM reps and a printed report on this motor)

2. My average mileage loaded for work is ........9 mpg.....with no cap and tools the best I can do is 17mpg highway

Great truck for the ride,capacity and power from a gas motor.......it cost me 41K new in 2003 and for $3,800 more I could have bought it with the Duramax. In 2003 my thought was ....." how could gas ever get above $2.25

The truck is paid for now and has 112K on it. I just bought a new (used) multi purpose vehicle to handle the heavy work of towing my trailers, mini-exc, skidsteer, etc. and am looking to replace this truck with a cheaper daily driver.

Great truck but..........go Duramax

woodchuck2

Most guys that i know of with them get 12-13mpg at best. I personally went with the D-max, fuel does cost more "which is BS, perfect example of price goudging" but i have gotten up to 22mpg on trips empty and still gets 10-12mpg towing my 14' v-nose enclosed trailer loaded. I towed my off-road truck to Raushes Creek in Penn. on I-81 last fall with a combined weight of 7500lbs doing 75mph with the A/C on and got 12-13 mpg.

dlcj

I love my d-max. Have 5 level programer and 4" exahaust. 450 horse power and 1000 ftlbs torqe. Have pulled a 10,000 lb bobcat/trailer on a crooked hilly road 100 miles. Run like it had no load at 55-65 mph and averaged 12 mpg. If i can keep my foot out of it it can get 24 mpg on highway unloaded. Hard to do though. Sad thing is, most of the time i drive a $500 s10 4cly 27mpg and gas is cheaper than diesel

JFRAME

I had a 04 chev hd 2500 exended cab w/ 6' bed ,295 tires' flow masters,KandN filter. I pulled a 16' doolittle cargo trailer set up for framing/trim,I got about 9mph towing and about 10.5 empty

Halo

Ditto here...

Have had two duramaxes (03 & 05) and currently have gone back to the 8.1. I did not feel the duramaxes were worth the extra cost unless towing hard and often. The mileage on both my duramaxes was very close to the 8.1 around town.