My best Highway MPG!

Daubs · November 1, 2004

Drove home from brother's house on Sunday. Loaded the kiddos, dog and all our gear from the weekend (duck hunting stuff and kidds stuff). Filled up the Big Block and reset the GPS. Did my best to keep my foot out of it to see what kind of MPG I could get from the 8.1

I have 285's and haven't called Westers yet for a chip upgrade, so my trip computer and odometer are a little off. Used the GPS to get accurate miles traveled and, are you ready for this, got a whopping 13.61 MPG!

I was very impressed. Previous high was 12.5 MPG. I guess that Volant intake is making a difference. Around town I'm getting 9.5 to 10.

c502cid · November 1, 2004

My best tank so far with my 8.1/Allison/3.73/Westers 87-91 dual tune has been 16.7 mpg using everything I knew trying to get good gas mileage. Usual mpg with regular driving is from 13-14.5. Never have gotten lower than 11, without my trailer of course.

Daubs · November 1, 2004

c502cid: That's GREAT! Tell me more about your truck. CC? Regular cab? What size tires.

You are getting MPG that I used to get with my 1500 Z-71 ext cab. I knew my 8.1 wasn't going to get good MPG, and I'm not bitching at all about 10 and 13 MPG. Better MPG would always be nice...

c502cid · November 2, 2004

c502cid: That's GREAT! Tell me more about your truck. CC? Regular cab? What size tires.

You are getting MPG that I used to get with my 1500 Z-71 ext cab. I knew my 8.1 wasn't going to get good MPG, and I'm not bitching at all about 10 and 13 MPG. Better MPG would always be nice...

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Crew cab, short bed, 4x4. The 16.7 tank was cruise on at 67mph, ac off, level ground mostly. Followed it up with a 16.5 so it wasn't a fluke. I'm sure the 3.73 gears have something to do with it. 265 tires but the Westers is programmed for them. Still, I'll get 13-14 mpg doing 80 with the cruise on and AC blasting. Other mods include True-Flow intake, and Magnaflow muffler. Other mods are suspension or looks so they shouldnt have anything to do with mpg.

chevhot · November 2, 2004

i have 34 inch tires 8.1 and im getting around 7 to 8 mpg got to love the big block

gas $ 195 for 87

2004HDCCinPA · November 2, 2004

hi guys,

i have an 04 2500HD crew cab with the 6.0.

it only has about 1400 miles on it and i have

been getting 13 in local driving. it is a 1/2 mile

more per gallon than my 03 2500HD ext cab.

Daubs · November 2, 2004

Crew cab, short bed, 4x4. The 16.7 tank was cruise on at 67mph, ac off, level ground mostly. Followed it up with a 16.5 so it wasn't a fluke. I'm sure the 3.73 gears have something to do with it. 265 tires but the Westers is programmed for them. Still, I'll get 13-14 mpg doing 80 with the cruise on and AC blasting. Other mods include True-Flow intake, and Magnaflow muffler. Other mods are suspension or looks so they shouldnt have anything to do with mpg.

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c502cid: Sounds a lot like my truck: CC, short bed, 4x4, 3.73's...but I have 285's. I've got a Volant, but stock muffler. Do you think the Magnaflow makes that much difference? How's the sound on that one? Just the muffler and not other parts of exhaust?

I'd love to see 16.7 highyway. What have you been getting around town?

Thanks, D.

MyYamR7 · November 3, 2004

I've got a 04 2500HD extra cab, 2wd with the 8.1 and allison, i get 13.5mpg consistantly with a 50/50 mix of highway and backroads. I've gotten as good as 14.8 mpg out of a tank and as bad as 9.5 while towing. Only mod as of now is some no-named brand air filter kit.

Mark