Larry

iTrader: (4)

How powerful is the 8100 engine and what gas mileage does it get? It has steel heads but do they flow as well as the aluminum heads on the 6.0?

Raughammer

Man.... I LOVE that motor.
The 5 speed Allison tranny aint too bad neither!

Neil 6.0

The one guy I know who has a 8.1 hasn't had any trouble with the motor, but is on his 2nd Allison. His truck is an early 2001 and the problems have been computer/software related, noting internally had failed.

A buddy of mine works in the oilfield and was telling me a story about one of the Ranchers that they check wells for. The rancher has a '01 2500HD ext-cab 4x4 with 8.1/allison. They say he abuses the living hell out of whatever he is driving. He drives that truck as fast as it will go down ranch roads that jeeps would be afraid of. I have seen this truck and it is no lie, this truck is beat to ****. The tail-lights are held in place with baling wire, the bed is cracked down both sides from the toolbox twisting the bed, the airdam is long gone, windshield is cracked to hell, mirrors are busted and there are dents everywhere. It's less than a year old and has over 40K on it. The rancher told my buddy the only reason he has kept the truck is because he can not blow up the motor. He got in the truck, started it up and then got a stick out of the bed and wedged it between the seat & gas pedal so it was running at WOT and walked off. He left it that way for a few minutes, just letting it bang the rev limiter the whole time.

wizkid

iTrader: (3)

We have 3 trucks with the 8100 engine in them. They pull way better than the 350 adn 454 sbc's that use to come in the 2500 adn 3500 models. They tow extremely well and get reasonable 10-14 mpg. Remember, our trucks gross weight are between 11,000 and 14,000.

Eric

Patrick G

iTrader: (14)

Larry,

Mike Senia has an '02 full size van with an 8.1L motor. He said the torque management program from GM really, really pulls down power. He said his 5.3L Suburban (also '02) has better punch off the line. His gas mileage is around 13-14 on the open road and 9-10 in town.

For all the added weight, I think the 8.1L motor is no faster than a 6.0L model when racing empty...as a matter of fact, I would bet the 6.0L would win...plus get better gas mileage and be much more "mod friendly". Now if you like racing when pulling a trailor, then I would give the nod to the 8.1L...just don't challenge a Duramax though...you'll get spanked!! <img src="gr_grin.gif" border="0">

449pacecar

I've got one, love it! Gas mileage for me has been 11-13 MPG ever since I've had it. Considering my 94 454 dually got 11 MPG no matter what, I think the 8.1 is right on par. Biggest complaint is the gas tank size, 26 gallons. That doesn't last long on road trips.

I haven't found out much about the heads, other than them being reverse cooled, like the LT1 motors.

Software was changed between '01 & '02, how much I din't know. I do know my truck won't rev past 3500 RPM's while in park. <img src="graemlins/burnout.gif" border="0" alt="[Burnout]" />

[ January 15, 2002: Message edited by: 449pacecar ]</p>

Larry

iTrader: (4)

Thanks guys for all the info! Looks like they just don't make the truck with the engine and gearing I want. I want a truck with Nine ***** engine. 382 cubic inches with 11:1 compression ratio which will prduce good low end torque for towing, a killer cam for good acceleration and tall gearing for economy.

Maybe I better keep this Dodge!

[ January 15, 2002: Message edited by: Larry ]</p>

CMNTMXR57

I also have one. An '02 2500HD, extended cab, 6.5 bed, 4x4.

When I first got it, I could leave rubber longer than I could with my Camaro, I think I left a nice long burnie about a block long with it. <img src="gr_grin.gif" border="0"> I also raced a mustang GT (95-96'ish) down the NW Tollway one day and up to 100mph when the speed limiter kicked in, I actually had to let off a couple times otherwise I'd have hit him (he was on it too as I could hear his Flowmaster's at full tilt). He finally only put about 3-4 car lengths on me when I hit that damn limiter. Keep in mind, this thing weighs 6,260lbs

Since then, I don't think it's making the power it should though. Granted I put some LT285/75/16 BFG All Terrains on in place of the LT245/75/16 Firestone SteelTex A/T's that it came with, but it shouldn't have slowed it down that much.

There is one common problem myself and a few others have noticed, primarily those of us in the northern regions where it actually gets cold. On a cold startup and driving, it has a "cold hesitation" problem. Chevy is aware of this and it is linked to the "live-by-wire" throttle body's software and as such they have a TSB for it. Once it warms up (the engine), it won't do it anymore.

Something that I've noticed is that my lifters after the truck has sat for an hour or so then I go to re-start it, tend to drain. Or at least they don't pump up that fast and as such, they tick away like crazy for the first few minutes of operation kinda like a tired old small block.

An item some others have noted is that some Vortec 8100's came with loose flexplates.

The only other problem I've had with the truck is that something fell off inside the driver's side door and rattles inside it each time I close it.

I also plan on doing a few upgrades to the truck that come from Chevy on other GM trucks that I think the LT package (which I have) should come with regardless of it being a 2500HD. Those are;

-Puddle lamps in the mirror. I'll get those off a Tahoe or Suburban.

-Steering wheel audio controls also off a Tahoe or Suburban.

-120mph gauge cluster off a Yukon Denali.

CMNTMXR57

Oh, as to my mileage, I'd bet I'm only getting 8-9 mpg as I tend to be heavy footed.

tbyrne

iTrader: (15)

The new issue of Motor Trend has a comparison between the 5.3 and 8.1 Avalanche. The 5.3 ran 16.5 @ 83.9 while the 8.1 ran 16.6 @ 83.7. The 8.1 is about 950 lbs heavier so it gives up about a second to the weight.

I've seen 11.5 MPG with my 8.1. That was a mix of city/highway driving.

Tom
2002 Supercharged 8.1 Suburban - Project underway now!
2001 Supercharged 6.0 Suburban-15.87 @ 88.41