My boss has a '03 2500 Suburban 8.1/4L85E/4.10/4x4 with probably less than 10K miles on it, he's only had it ~6 months. So far he said his doesn't burn any oil or have any piston slap. Says it gets 9 mpg, but that is all city driving. I've driven it a few times and can feel the torque come on alot sooner than my truck. I imagine it would do a good job of pulling your T/A to the track. I've told him that when he is ready to sell it to let me know, I want to make an offer on it. I also drove a 8.1/Allison Crewcab back when they first came out and that thing was a beast...nailed it going 30 and tires started shredding.

FYI: My 6.0 is only getting 11-12 mpg, so you can see there isn't much fuel to be saved by going that route.

 

FWIW, the duramax holds 10 quarts of oil. Oil filters can be found for less than $10 each and Shell rotella T oil 15w40 is usually 5 bucks a gallon. Oil change in the truck with that oil costs me about 20 bucks. Also, the duramax only needs to have its oil changed once every 10,000 miles.

 

Tony ... in reality, I think I would prefer the 6.0 in an LD. But it all comes down to availability and price. My budget puts me in the $20K range ...

Because the 8.1 is a seen as a gas hog, it's price is considerably lower right now in the used arena. 6.0s fetch an additional $1-1.5K, with everything else being the same. Factor in I usually only put 6-8K miles a year on a vehicle, the operating costs will be managable.

Nell ... the research I've done on other forums, specific to the 8.1 Vortec, shows me that the BEST anyone gets is 15 (and I question that) and the worst is 8 (towing 12k lbs at hiway speeds or in a motorhome). So, I figure 11-12 for me and my driving habits is easily achievable. I get 9-10 with my F250 w/ a 460. Friends with 6.0s get 12-13.

Jorday ... thanks for the update.
Again, had a diesel ... never again ...

 

Well ... it's sitting my driveway ...

 

I have a 2500hd 8.1l/allison it gets about 12mpg to get 13mpg you have to run 85mph towing a 1/2 ton truck I got 9mpg running 80mph. I never had an oil problem until I installed a new cam but I did see that intake sucking oil into the runners so I think that my new oil use problem.

An old man told me that the added cost for a diesel and oil changes it take 8 yrs to pay for its self. He was a full time RVer and traded his durmax off on a 8.1L and so did 6 more peaple from his club.

There's a lot power can be found in a 8.1 mine is making the same rwtq as a D-max add some n2o and you can woop-on some big headed diesel owners.

BTW I am the nut thats spraying 200hp to poor 8.1 my friend posted my dyno# a month or so back .

 

The first couple of tanks have now gone through it.
I towed a couple of cars a portion of it.

Overall, I got 11.8mpg. Not bad considering the towing and the showing off ...

Hasn't used a drop of oil, that I can tell.

 

The first couple of tanks have now gone through it.
I towed a couple of cars a portion of it.

Overall, I got 11.8mpg. Not bad considering the towing and the showing off ...

Hasn't used a drop of oil, that I can tell.

 

11.8, not bad considering you have 130ci more than my gas hog.
What are the specs on your rig Mitch? Crewcab? 4x4? etc...

 

I have owned 2 HD's in the last 3 years one a 8.1 the other a Dmax.The 8.1 got 6.5 mpg pulling my 8000 lb 28 ft trailer,the Dmax 12 mpg.8.1 would scream up the side of a hill on the limiter while the Dmax loafs at 2100 rpm.8.1 burned 103 qts of oil in 58,000 miles and averaged 9.7 mpg overal in the 2 years I had it.Dmax will use a qt every 5,000 miles.Baldwin B1441 oil filter costs 6 bucks at the local Kenworth dealer.I use 10 qts of Mobil synthetic in the Dmax and change it every 10,000 miles.I paid $3990.00 for the upgrade and never looked back.By comparing fuel and maintenance costs I have already saved almost $2,000.00 at 23,000 miles over my old 8.1.And at 100,000 miles when I get rid of it the truck will command a 4-6k premium over a gas truck.All these positives and it will smoke a gasser in the 1320.I drove from Panama City Beach Florida to Columbus Ohio last week in my Duramax crewcab 4x4.I drove 865 miles in 11 hrs and 40 minutes and stopped for fuel once 560 miles into the trip.And I drove fast enough to get a 83 in a 55 ticket from a Alabama state trooper in Ozark Al.Truck got over 18mpg at those speeds.A gasser will never deliver these numbers.I understand guys not buying them for whatever reason,but the they cost more argument doesn't hold water.A diesel truck will always be cheaper in the long run than a big-block.Fuel cost vary by state but I plan on breaking even by about 45,000 miles on the upfront cost,the 4-6k premium over a 8.1 I'll get at 100,000 mile trade is just a bonus.

 

Hey 422 SS the RV guys never did mods to there trucks and where always towing. The 8.1 was second choice this truck was at the right price at the right time. My first was a Dmax. A good friend has one on quodzilla 100 hp setting he is 2 tenths faster then me on motor. There is no doubt that I do not have the low end TQ of a diesel but I never had problems towing it does shift down to drive sooner than a Dmax but I never had to go down to third yet. Gas milage sucks when not pulling a trailer I can not come even close to a Dmax but towing its not soo much of a difference. I get a little tired of bashing on the 8.1 like it's not worth the iron there made of.The Dmax is great engine I love the power they can make but the allison has trouble holding the crazy TQ when you start playing whith them. BTW with the help of a 200shot of N2O I've cut the 1320 in 13.04@104.97 so far what it lacks in TQ its made up for it in HP.