Duramax Mileage - 22 MPG?

[Westro]

Frankly this is a nit with me, I'm tired of people claiming these high mileage numbers! Can you help with this argument.

I don't have any data to support an argument with my buddy. He wants to move up to a crew cab, short box, 4x4, 2004 2500 Chevy Duramax from a gas and states the duramax it is an obvious choice because the current owner claims 22 MPG average. He will use this for little to no towing and the towing he does do will be below 4000lbs.

I'm flabbergasted to believe that this truck will AVERAGE 22MPG. Anyone have real world data to show the inharent 22% mileage increase from gas to diesel is eaten up by the nearly 20% increased in diesel fuel price over gas?

[brotherxb]

I know 2 people that claim that kind of mileage with a duramax. A 2 wheel drive with just a superchip@24. A 4 wheel drive with a air intake and bank's dual exaust and chip @23. I have gotton 20 with my 01-7.3 auto with 3.73 gear's. But that was before they went to the new ulsd.I'm lucky to get a tad below 18 on the highway now,like 16.8 to 17.8

[NBhunter80]

the current owner claims 22 MPG average

Obviously the guy who is trying to sell the truck will say things that makes potential buyers happy (ie state great fuel milage). Second, the word "claim". Alot of people "claim" to get 22mpg with their f-350 psd. I get 12-13mpg on mine (with lift, tires, extreme programming etc). I highly doubt anyone driving a diesel v8 gets 22mpg unless it is lowered and they drive like grandmas. Tell your buddy to go fill up, drive the truck until empty and get real fuel milage estimates before buying the truck. Something tells me buddy selling the duramax claiming 22mpg is talking out his butt. You are probably justified in not believing him. I think duramax is better fuel economy than powerstrokes, but not that much better.

[Westro]

Would be nice if someone had an excel sheet on ACTUAL mileage of a similar truck. I know I have mileage numbers for lifetime of my vehicles.

I'm guessing this used truck he quoted him a single tank high mileage. I can tell you and show you that my truck has averaged 15.8 mpg the lifetime of my one ton. And I will claim that as pretty darn good considering how much time the gooseneck trailer stays attached to it.

Nice to see that most of use believe this as bull. Anyone have hard data on what kind of mileage these trucks bring?

[MarkEkberg]

Is it possible? Absolutely!

I have driven three different poswerstrokes and three different cummings over the last 10 years.

Everyone was the same. Drive easy, keep the rpm's down and you will yield 20-23 depending on your speed.

Once you start getting past 65 the mpg drop quick.

On my personal truck at 65 I am at 19.8, at 75 I drop to 17 even. If I slow down to 55 I jump up to 22.5.

It is all how you drive, not which one you own.

[mannytranny403]

I have gotten 22 mpg with my Dmax.

All highway, 10% AC use, 2000 ft elevation, one full complete tank. CC/SB 4x4 truck, 6 speed manual, running biodiesel and a chip that advanced the timing. Cruise control set at 65 for the whole fricking tank. Ugh. It did get 22 mpg, however.

Much faster than 65 and the mpg takes a dump, fast.

[BigDaddyT]

A cummins owner with a 96 claimed 29. Had lots of documentation to go with it. My personal best was 26 but I could pull 22-24 regularly.

[macmaniac1]

A friend of mine got 25mpg out of his chipped 01 f-250 7.3 that he used for sled pulling.

[drcampbell]

If I get elected to Congress, I'll push for eliminating the exemption saying 3/4-ton (& up) trucks need not have their fuel economy performance tested and posted in the window.

[DirtFarmer]

My 7.3 will average 20-21 under the very best of conditions.

My folks live in Albuquerque, NM and on the return trip from there to West Texas, I'll get over 20 if I am running empty and keep the speed down. But this trip includes a two thousand foot drop in elevation and a prevailing tailwind.

That said, the same truck has averaged 15.5 overall since new.

There is a big difference in the overall average and a best case figure.

[whiteoj2001]

I agree with most people here that once you start cruising in the highway over 65 MPH that fuel economy decreases significantly. This is due to the poor aerodynamic profile of the truck in general; high coefficient of drag. I get 20 MPG with my stock F-250 powerstroke with a tonneau cover if I keep my highway speed around 65 MPH. You will notice that cars that have high fuel economy like the Prius have a very aerodynamic profile, kind of like the high speed French TGV train, which clocked 357.2 MPH (574.8 KPH). There is an interesting guy named Phil Knox who has streamlined a 94 Tacoma EVWORLD FEATURE: Free Fuel Riding on the Wind:KNOX | TOYOTA | TRUCK | AERODYNAMICS | STREAMLINE | EIFFEL | TEXAS | PHIL and significantly increased fuel ecomomy.

[BLOWINSMOKE99STROKE]

average of 22? no way! my buddys d max's lieometer says 25 on the highway at 63mph. hand calc was 23. but in town he sees about 15-17. so the average drops a little. if the are seeing 22 avg, is must be granny driving 24/7 on the highway!

[69mach1377]

Here's a good one. A Hemi work truck that gets mid 20s. HaHaHa. The guy who installed a window for me recently made that claim.

[Kaliburz]

Anything is possible.... but how probable??

On a nice cruise drive, the best I saw a friend's dad's '94 or '95 7.3L PSD was 24/25MPG. We calculated it when we filled it up. BUT this was driving 50-55 (60 TOPS) with the 5 speed tranny in OD! It was cool mountain air, not many hills either, slow gradual rises and he was not putting his foot into it.

I just recently got a bit over 17 MPG on my '90 7.3L IDI 1 ton van. BUT, I have the 3.54 rear axle and I was running 60-65 mph. I was happy to break 17 (first time ever, but only had the van for few months).

People have claimed to get 22-24 MPG w/ the old 6.2L in the half tons and Blazers. But this was w/ the highest (low number 3.08 ratio, if it was avail). Others say the 6.5 and 6.2's couldn't get that good, even w/ a OD and correct ratio.

A guy w/ an 89 Dodge claimed high 20's. But he said he swapped a OD manual into his truck which had a 3.04 rear axle ratio!

[Kaliburz]

Just chatted w/ a friend w/ a 6.6 who uses it for work. His log, as required by his work for fuel ups- states that he's avg. 15-16mpg. Most of the time he's empty running. But when he tows, he tows HEAVY- 5 ton loads, not including the trailer. His best record ever was 17-18MPG. He's gonna be going on a trip towing and loaded soon on the free way, so he's gonna let me know how it will do (Labor Day trip).