8.1 L engine

[cahydejr]

I was talked into the 8.1 L engine. I plan on pulling a 5th wheel at max 12,000 lbs. I am not happy with the regular driving gas mileage with the 8.1. Also I don't like the Allison which won't go into OD until 45 MPH. This is with no load and easy on the gas.

 

The best I have received is 12 MPG with no load. Am I wrong for thinking I should get more? The darn truck seems like it is running with the brakes on. They aren't!

[tmf6902]

Now the milage I can't help you on, with no load I probably get about 11.5, but the OD, I'm pretty sure mine kicks in correctly at just about any speed it should.....have you talked to the stealer about it yet???

 

 

my 11.5 mpg is with 315's....so that ain't bad...with the blazer i get about 2 gallons to the mile

[dunedog]

My fuel economy is about the same. Towing aroun 10 mpg. I have had mine for about 18 months and I love it. I have had no problems towing. The most I tow is about 9-10 thousand pounds. (depends on how many tows and gear we put in the toy hauler).

[Rippem]

I hate to be the one to tell you...but they don't run 500 inch engines in economy cars for a reason If you thought you were going to get 15+ MPG with a 500 cu in engine in a 5500 lb truck that rides high...don't bogart..pass it this way! I get 10-11 ave mix driving with my foot in it (always). I pulled 13 out of a tank once. I pulled 8.2 - 8.5 MPG towing my 12,000+ lb boat on a 600 mi. road trip recently. I'm happy with that, and the towing performance...I was impressed...the best power of any gasser I've towed this kind of wieght with. In tow/haul with the a/c on and cruise set at 65 mph. Seldom saw the top of 3rd. I was suprised what it would pull in O/D for grade. By the way 12 mpg unloaded is as good as anyone is getting. I like the fact that with 265's and a 3.73 gear....= 90+ mph @ 2500 rpm in O/D. She's got legs...mister!

[HendyPhoto]

If you wanted better mileage, you definitely should have gotten the louder, smellier, smoking engine. But the the Tow/Haul mode should work at all speeds. The mileage sucks, but the 8.1 is more fun to drive. Although, under a load, there really isnt that much difference in gas mileage between the two. 12 MPG is pretty good, talk to some people who drive the old trucks with 350's and 454's, the economy is even worse than the 496 8.1!

 

Too bad your salesman didnt care enough to tell you the difference in the two engines

[f7_ditch_jumper]

I can get 15MPG out of my 8.1 w/5 speed ally + 3.73 RE. Just be glad you didn't buy a 6.0 thats only available in a 4.1 RE because it gets worse to same MPG with less power. You really didn't think you were going to get 68MPG did you?

 

You should have bought this.

[katie-bug]

I have acheived up to 13.5 miles per gallon, but average between 11 to 12 miles per gallon with my 8.1L/Allison, 3.73 rear end ratio. The average mpg is regardless of driving style, foot into throttle or not. Mine seems to shift into overdrive as a function of throttle. Light on the throttle and it will shift into overdrive around 35 to 40 miles per hour, or heavy on throttle then let up on it and it will shift to od.

It is a guzzler, but will accelerate uphill without downshifting

[chiefsshop]

I average about 10 mpg in the city and 13 on the highway. the worst mileage to date was when towed my 94 chevy 1 ton stake rack to Texas, I didn't weigh it but I know I had to have up around 20000 gross,the truck felt heavy. So keeping up with traffic I got around 6mpg for 1800 miles

[bummed-n-Md]

I didn't notice how many miles you have on it but here is my experience:

 

I just turned 35K (16 months of driving).

 

In am now getting a steady 13.5 mpg . I drive an average of 30 miles one way to work and use this primarily as a daily commuter (13.8 best so far). Open highway with cruise set to 70 (when in North and South Carolina ), I can hit the low 14s.

 

I do on occasion haul gravel and rock (for landscaping projects around the house) and lumber when doing local charity work.

 

When I first got the truck I started out with 12.5 from day one (summer fuel). In winter, I got a steady 10.5 to 11.5 (depended on warm up time in the mornings and road conditions). Worst I got was low 8s when there was 12 inches of snow and I was in 4x4 for 2+ days.

 

Power has never been an issue. This thing (100% stock) will just sh!t and git, even with over 2000 lbs in the bed.

[HendyPhoto]

F7 Ditch Jumper, LOLOLOLOL

[MarkD]

I hate to be the one to tell you...but they don't run 500 inch engines in economy cars for a reason

 

LMAO!

 

You may want to try a Westers. haven't some people reported mpg improvements?

[tmf6902]

I average about 10 mpg in the city and 13 on the highway. the worst mileage to date was when towed my 94 chevy 1 ton stake rack to Texas, I didn't weigh it but I know I had to have up around 20000 gross,the truck felt heavy. So keeping up with traffic I got around 6mpg for 1800 miles

d**n.....that must have sucked...what'd ya do stopp for gas every hour???? LOL I just did the math you had to stop for gas atleast 8 times.....man.....

[CMNTMXR81]

You're getting 12mpg with a 500 cube motor and you're complaining!

 

Sh*t, I'm lucky to get 8 mpg and MAYBE 9 mpg if I pu$$y foot it. I didn't buy it for fuel economy!

 

Just like people I tell that I have a truck with a 500 cube V8. They usually reply "ohhh, that must get terrible fuel economy!" No sh*t sherlock! But some of us rank fuel economy down there with colonoscopies!

[tmf6902]

no no no I'm not complaining. I do think however for a 500 cu inch engine and 12 mpg they could have squeezed more than 345 horses out of it. Shoot I would drop to 7 or 8 mpg if it meant getting 100 more HP

[Hacksaw Hilliard]

I was talked into the 8.1 L engine. I plan on pulling a 5th wheel at max 12,000 lbs. I am not happy with the regular driving gas mileage with the 8.1. Also I don't like the Allison which won't go into OD until 45 MPH. This is with no load and easy on the gas.

 

The best I have received is 12 MPG with no load. Am I wrong for thinking I should get more? The darn truck seems like it is running with the brakes on. They aren't!

Yes the DMAX will get better fuel mileage but is it really worth the extra $4000? With fuel prices being what they are, you'd have to drive over 200,000 miles before you break even. The only reason to buy a diesel is for the extra power you'd get over the gasser (unless you've got money to burn).