6.0 or 8.1 in new tow rig?

I am looking at about 4 different 2005 Chevy Suburban 2500 4x4 and I am trying to decide which engine is best. I'm really looking for the engine that gets the best mileage as the majority of the miles I put on it are not towing. I'm sure the 8.1 gets less mpg but is it significant enough that I should eliminate it from my considerations?

And dont say, "Get a Duramax!" I've already tried that and the wife is convinced the crew cab trucks are not good family vehicles! Oh Well!

That 8.1 will do better towing for mpg and power, plus it might have the allison tranny in it thats a big plus.

I have 180,000 miles on my 8.1, and it has been awesome. I get consistently 11 mpg towing or not, but with 455 Ft/Lbs of torque, it will pretty much pull your house down the street, and I just idle up the ramp in 4 wheel low

Seems like you should be able to beat the 11 mpg non-towing figure with the 6.0. I have buddies with that engine in their 2500 trucks that do better than that unladen.

If fuel economy is a major concern you can easily trump both those engines with a Powerstroke Excursion.

I had a 2005 2500 HD with the 6.0, lots more power then expected out of a 6 liter, but horrible MPG towing, I have a buddy with the 8.1 w/Allison trans and he was getting much better MPG towing and able the same MPG as I was when not towing. If you can go for the 8.1. Neither gets good milage as a daily driver. I moved on to an Excursion with the 6 litter Power Stroke and I get much better towing performance and better MPGs towing or not then I did with my 6 liter gasser. I was never a Ford truck guy, but now will not go back.

Things I found bad on my GMC 2500.
The front end sucks, steering boxes are POS, they use the same steering box on a 1/2 ton as they do on their 1 tons... NOT GOOD, went through 2 in 68K miles. If you lift it the problem will show after 10K miles
Then the problem with the center link and steering knuckels, induced by the steering box.
Engine began to idle as if I have a crazy Cam in it at idle, went to the dealer, said head was bad and it would take 2800 to fix. WTF a 4 year old truck with 68K miles needs a new head.....

Out with GMC in with Ford. I LOVE my Excursion, after this one is dead I am thinking of having this guy build me a new one using an 09, 2010 F250 as the chassis.

www.customautosbytim.com

Johnny,
The Excursion with the Diesel was on my list but I'm not sure it will fit in my garage! Do you know what the width of the Excursion is including the tow mirrors?

What boat are you towing? My Avalanche (same chassis as 'burb) is only 1/2 ton chassis with 5.3 and pulls my 4200# Cobalt like nothing. Is there another reason you need a 3/4 ton chassis besides pulling a boat?

"pulls my 4200# Cobalt like nothing. Is there"

I always find it entertaining when people say this. Seriously exaggerate much.

^^^ Ok so I know its there. What I am saying is that it pulls it without a significant amount of effort. If that was all I had to pull, which it is, I certainly dont see the need for a much heavier chassis and thirstier engine. My 5.3 gets 13-14 while towing my Cobalt. Was just trying to make a point and may have exaggerated a bit. (Which of course never happens on this board \clipart ){lame}

(Message edited by drknute3 on June 29, 2009)

Yeah I find that hard to believe Bill. I pull an X2 that with tandem trailer and gear is about 5000 lbs and my 99 burb with 5.7 definately knows its back there. I like to have more than I need and the ramp I usually launch at is very steep, about 1/3 mile long with about 75' elevation change, hence the 2500.

I would go with the 8.1L. The 6.0 does ok but I just hate having to run the engine at such high rpm's when towing on hills and such.

BTW - the 5.3 sucks for towing. I would take a vortec 350 with 255 hp over that 5.3 any day. I traded in my Chevy Avalance on a new duramax because it lacked the low end grunt that I was looking for(up here in Colorado anyway). I've driven 2 supercharged 5.3 Tahoes and those were bad azz, the supercharger gives you the low end that you need.

fwiw, i have about 47K on my 06 6.0 and my overall average since i've bought it is 13.4 MPG.

Thanks Bruce that helps! 13.4mpg is better than I get in my current Suburban. And your Denali has full time 4wd right? In theory that may cost 1 mpg?

I like the idea of the big block but know that most of my driving is around town with an average tow distance round trip of about 10 miles. Occasionally I like to go to other lakes or tow to my dealer 200-400 miles round trip thru the hills of KY and TN. More input is appreciated, I want to get this one right!

yeah, it's AWD and i've been very happy with it, but my boat/trailer combo isn't on the heavy side either so that probably helps a bit. still no issues with driving the mountain passes though. it does great. are there better? sure. great rig in town too imo. i'd buy it again. if i drive slow without towing i can get 14'ish (but i don't)

8.1... As stated many times above, they basically get the same mpg..

I have a 03 Suburban with the 5.3, and it tows my boat great. I also have an 07 Duramax BTW. Before I had the Duramax, I had an 04 F150 with the 5.4...Now that thing was a DOG....If most of you miles are going to be not towing. I would go with the 5.3 . I get about 18 on the highway, about 14-15 in town, and about 13 towing.

As you mentioned, diesel is out of the question and I went through the same thing with my wife. The GMC dealer called when they got their first Duramax diesel, I took my wife for the test drive and drove home with a Denali XL.

I agree with the earlier post about the excursion being the best of both for room and towing. However, the 6.0 is more than enough. My set-up is not light and we tow over a mountain pass every weekend. I now have the Sierra Denali. You can't get a better ride than the XL or suburban with autoride and load leveling suspension. Even though it is a 1/2T the Denalis and Escalades, have heavier brakes and transmissions than the normal 1/2T and with both you get the HO 6.0. I average about 16.4 with highway and city driving. Strictly hwy is about 17-18 and that is with 4:11 rear end gears. My XL got about the same with 3:73s. Towing (65mph) with about 3,000ft elevation change each way I only average about 10-11. I do have a CAI and a Westers custom tune that helps. We also make about 4-5 trips to Shasta each year wich is about 300 miles each way and two mountain passes (not hills) and it is fine. We are able to pass with no problems too.

I wish I had the seating room of the suburban back (and the autoride and load leveling). The 8.1 with the Allison is sweet, but if 80% of your mileage is empty and it has the 4:11's, get ready for a constant 10-12 loaded or not.

And, yes as Bruce indicated the right foot weight / gas milege correlation can make things worse, but it's fun.

Good luck.

07 6.0 with 4/10 rearend and was about where Bruce was at and then did a bullydog triple dog programmer and gained about 1 mpg plus a few extra ponies
straight highway 17- 18 mpg
combination(city/ highway)14-14.5
towing(very steep hill for 2 miles) appx. 9.5-10.5
02 xstar single axle trailer(not sure on wt.)
and FWIW had a 1500 with 5.3 and 355 rearend or whatever they put in those cookie cutter trucks and lost top 2 gears in tranny a month after 100k and two weeks later blew rearend out, so if you have steep hills to contend with I would at least go with 6.0 and 4/10 rearend
my .02

There is no replacement for displacement.

If you have the choice, get the 8.1 ~ 496 cu. in. It's basically a stroked out version of the tried and true 454, giving it tons of low end, low rpm torque.
It doesn't hunt for gears, even on the steepest grades. If you do opt for the 6.0, make sure it's got a 4.10 rear end.

I have an 02 Duramax love it and it does make a good family vehicle, only problem is that Ive got more little bums than seatbelts That's when my 04 2500 burban comes in!! its got plenty power with the 6. liter and pulls the boat just dandy. I thought that the 8.1 was a little excessive and spendy for fueling so I stayed with the 6.

I like to have more than I need

...

most of my driving is around town with an average tow distance round trip of about 10 miles



It's ok man, we know what's really going on. Get the biggest motor you can afford, and don't forget how important the lift is for being able to see behind the boat while towing.

I would get the 8.1 over the 6.0, gas mileage is the same, but 8.1 power is better.

How much towing are you doing?

A 1500 with 4:10 gears will be fine for an X2...

No lift is in my future Nate, but thanks for the concern. I also noted that I like to tow my boat a few times a year to surrounding lakes up to 200 miles away. I want my truck to tow the boat with ease and the 1500 is not doing the job.

Thanks guys for subtly correcting my heavy use of the "1" key. It should have been 4:10 gears in my previous post not 4:11. The gearing makes a big difference. A 1/2 ton with a 6.0 and 200 miles will not be a problem, but the torque of the 8.1 is great.

You will have to be the judge of weather or not the everyday mileage is worth it. My friend's 8.1 Yukon XL never gets more than 12mpg. About 10-11 towing his 32 Scarab, but he tends to drive a little fast.

8.1 vs. 6.0 -- No contest! 8.1 hands down.

I have a 8.1 Suburban and I love it. It will pull ANY boat with ease. Yeah the mileage sucks, but so does the 6.0. Pulled 29' travel trailer and a 26' snowmobile trailer with no problem. 65mph up most passes and have plenty of pedal to spare.

Don't waste your time with a 6.0.