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Discussion Starter · #1 ·
Duramax or 8.1L that is the question....

What are the pluses of both? I'm guessing the Duramax gets better MPG, but diesel costs more. They both seem to have the same towing capacity, but 8.1L beats it in some towing areas. Cost seems to be in the same ballpark for both vehicles. So what is the determining factor for you guys? Longevity?

Thanks,
Mav
 

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I have no experience with both myself, but I have a friend who has had both. He will not go back to a gasser, was the message he made clear. I wish I had more specifics, but fuel mileage was one. I think he got 9 mpg with the 8.1 whether he was towing or not. The diesel he's getting 15-16 and 12-14 towing I believe.
Sorry I don't have more info than that. I think he told me the 8.1 had more snap to it but the duramax didn't leave overdrive when towing near as much...don't quote on that.
 

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I work with a mechanic who has a GMC with the 8.1, and I can tell you that all things the same i.e. trailer weight, load height and that kind of stuff, that his GMC couldn't keep up with my old LLY in any category, he used my car hauler to go get his moms dodge caravan and got 9 mpg pulling it, I bought an89 3/4 ton 4x4 suburban with a grenaded t-case and got 12.6 mpg pulling it on the same trailer, plus when we leave the shop after work he has never been able to pass me or stay in front when I go to pass, but don't get me wrong, it's a pullin' mofo considering it doesn't have a turbo, there isn't any other stock big block or V-10 that will out pull a stock 8.1, so it's just your preference in fuel really that makes a difference, but I for one would rather have a turbocharged diesel that makes more power with the same amount of fuel than a naturally aspirated gasser!
 

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A buddy in the same business we are in used to run 8.1 in all his stuff. One evening we were coming home late after working most on f the night on a project, I pulled over to make sure I had the safety chains on the trailer. He pulled in behind me, chains were OK so off we went. As son as I had it on pavement, pushed it to the floor. A cloud of smoke and I was gone, he couldn't keep up. Both were '03 2500 4wd. His was 8.1, mine Duramax with a Super Chip in the towsafe mode. He had a fiberglass service body with about 1,000 pounds of tools. Mine was a straight PU with tool boxes, probably the same, maybe a little less in tool weight towing a single axle trailer with about 1500 pounds on it.
Best mileage he ever got was 14.5. I get 21 if I leave the cruise on and don't drive it like a sports car.
Have pulled loads just a little over rated towing capacity, did just fine.
He now has traded all of his gassers away for diesels, got 3 GM's and 1 7.3.
No won't even consider a gasser for my next service vehicle. Now if GM were to put a diesel in a 1500...................Oh yes! Better get on that idea before Toyota beats them to the punch.
Now if I had to get a gasser, would be the 8.1, nothing else even comes close.
 

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Got a buddy in the same line of work. He had the same model and year '03 2500 4wd but with the 8.1. Best fuel mileage he ever got was 14.5. I usually get 21 highway with the cruise on.

One evening late we both pulled out on the highway from a work site, I mashed it all the way down and held it to a little above posted. Left him in a cloud of smoke, he couldn't begin to keep up. I had a trailer and about 1500 pounds more weight than what he had. Super Chips in the tow safe mode.

Usually leave it in the tow safe mode and get 21. In the performance mode, driving it like a sports car, it drops to 16 or so but sure is a lot of fum.

Buddy got rid of his gassers and has all diesels now. 5 GM and 1 7.3 PowerStroke.

By the way, a chip will also raise your top end, al the way to red line on the tach. Depending on your gears will depend on the actual speed but it will be above 100.:cool :cool

You get a better take off in 4 wd, more traction but be mindful that the transfer case might not handle all those ponies. Mine didn't, Chevy wanted $3500, neighbor who runs a speed/performance oriented garage rebuilt it for $1600 and guaranteed it would not break because of power, ever.
 
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