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8.1L Gas Mileage

ptmeyer84

What is your average gas mileage with a 8.1L?  

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ptmeyer84 Enthusiast

ptmeyer84

Posted
Posted

Post your truck's model, gearing, performance upgrades and relative city/highway percentage. I would like to see just how much worse the gas mileage is compared to a 6.0L. Thanks

moo snutz Enthusiast

moo snutz

Posted
Posted

Hey ptmeyer84 - I get between 11 and 12 average with a daily commute of 30 miles (40/60 city/hwy). I've got 4:10s and 265/75s. On pure highway trips, I get close to 13.5 - not too bad at all. I just put on a TrueFlow air intake and didn't notice an increase in my daily average - probably because I get on it a little more now :confused: BUT I just got back from a 550 mile rnd trip camping trip down into the Navajo Nation in AZ with a 2500lb slide-in camper & got 11.5mpg !!! I normally got 8-9 with the camper. BTW - I live at 7000ft.

 

Take it easy & welcome :crazy:

Daubs Enthusiast

Daubs

Posted
Posted

Good poll.

 

I'm driving 04 CC 2500HD with Big Block / Allison combo. Have 3.73 gears and 285 REVO's. Started off in the 8.5-9 MPG range around town and 10-11 MPG highway.

 

Changed intake to Volant cold air system. Got Westers tune and asked him to change spedo for tires and give me good MPG. Now I'm avaraging around 11-11.5 MPG city. And getting 13-14 MPG Highway.

 

Only complaint I have is my engine has developed the cold start knock. Aside from that I'm very pleased with the Big Block. Loads of power and pretty darn good MPG for a 496 cid engine!

dewfpo Senior Enthusiast

dewfpo

Posted
Posted

12.02 mpg average since new (hand calculated not DIC, DIC reads high), 95% rural, no city, 5% highway. High Altitude.

Bone Stock 8.1L 4x4 with 4.10's

 

If I reset the DIC while on the highway and set the cruise at 65 mph I can break 14 mpg. :rant:

 

DEWFPO

dewfpo Senior Enthusiast

dewfpo

Posted
Posted
I thought the 8.1 only came with 3.73 rear end.  Are 4.10's an option?

 

 

 

 

 

Your thinking of the Duramax.

 

DEWFPO

Wirenut Enthusiast

Wirenut

Posted
Posted
4.10's are an option and I have them. Also, 295/75R16 tires, 4" lift and I get between 9-10 in town. Towing the 5'er, 6-7mpg.

 

 

 

4" Lift and 295s I would have thought your 5er rear bumper would be draggin' on the ground :rant: Nice scenery in the background (PICTURE)

 

 

 

2001, 3500, 285s, 4.10 I get a tiny bit better than 11mpg on the highway.

7mpg towing my 11,400 fifth wheel.

Cheekster96 Enthusiast

Cheekster96

Posted
Posted

2006 2500HD with the 4.10s. regular cab and 4x4.

Got the six speed ally with it, awesome! Double overdrive gear is nice with the big block.

I am not much in a hurry when travelling out on the turnpike..generally do 65-70 mph. I dont have the steering control buttons so i dont know the instant fuel mileage but after a fill up, i generally average 11.5-11.9 mpg. I dont tow. Truck just turned 2500 miles.

Everything is stock.

I did have to replace a tail light because it burnt out and that was about 200 miles ago.

Later

Lee

rlarson Enthusiast

rlarson

Posted
Posted

11.5-12 for me on my regular daily comute 80/20 highway/city with an 04 3.73 gears and 265/75's only mod being westers pcm which made no noticable change in mpg (which was my biggest reason for spending over $500)

Trouttrooper Enthusiast

Trouttrooper

Posted
Posted

11-12 mpg empty

10-11 mpg loaded

 

4:10's Allison, crew cab, long box, 3500SRW

 

 

My old truck....1999 GMC 2500LD 6.0, 4:10's, extended cab, long box

 

15 mpg empty

6-7 mpg loaded

 

 

Since my truck most often is towing or hauling a load it actually makes economic sense to own the bigger engine. My yearly average mpg is better with the 8.1 then when I had the 6.0

linda Enthusiast

linda

Posted
Posted
Post your truck's model, gearing, performance upgrades and relative city/highway percentage.  I would like to see just how much worse the gas mileage is compared to a 6.0L.  Thanks

 

 

 

 

2003 ECSB 4x4 Allison trany

whipple supercharger @6psi

Dmax intercooler

4.10 rear / G80

 

I have no idea what i get for gas milage and i love it. Its gotta be single digits because i find my shoe getting stuck to the floor with the gas pedal underneath it everytime i go out on the road. Its like my foot is made out of lead or something...LOL

Shooter_va Enthusiast

Shooter_va

Posted
Posted

I get between 10 and 11 average around the area I live, 12 to 13 Hwy and 8 to 9 towing my 10k lbs 5er. I've got 3:73s and 265/75s on my 2001.

Bart2500HD Enthusiast

Bart2500HD

Posted
Posted
I get between 10 and 11 average around the area I live, 12 to 13 Hwy and 8 to 9 towing my 10k lbs 5er. I've got 3:73s and 265/75s on my 2001.

 

 

 

 

Shooter,

 

How fast do you drive pulling your 5er? My 5er is about the same size and our trucks are basically the same, except I have an extended cab and 4.10's in it. I usually pull at about 65mph with the tow mode on and never get higher than 8mpg towing. Of course where I tow there are hills and I usually have to fight the wind too.

dco111 Enthusiast

dco111

Posted
Posted

I have a 03 3500 crew cab with duals. Before the wait 4 me I got 5-6 pulling 9-10 empty, after 8-9 pulling and 12-13 empty. I have a 28' fifth wheel weighing around 12000. I run anywhere from 65-80. LOVE that tune.

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