I have recently purchased an'08 sierra 3500 HD 4x4, but I am wondering why the 2500HD has 353HP, while the 3500HD is de-tuned to 312hp? Is there a simple way to get that 41HP back? I'm assuming it has something to do with emisions? Thanks

 

Did you buy the 6.0L or the 6.6L Duramax?

The Duramax is rated at 365hp with the single or dual rear wheels. The 6.0L gas is rated at 312hp ina dually.

 

I have the 6.0L gas, Single rear wheel. I have not found anything saying that just the dually is detuned to 312HP, but that could be the case....Any idea why they would detune HP?

 

Here is where I got my facts from.. http://autos.aol.com/cars-Chevrolet-...-2008/overview

Not sure what the reason would be to de-tune the 6.0 inthe dually. The duramax ratings are the same in either configuration.

 

It could be a combination of cam profileand ECU programming leaning towards torque and longevity. So horsepower and peak rpmof the 6.0L gas engine is stepped down from 1500 to 2500 to 3500. They probably figure that the heavier duty the truck, the more load you are going to carry and a high reving engine would tend to rev higher/longer pulling a heavy load.

My2008extended cab standard bed 4WD 2500with 6.0L 6-spd is probably peppier in normal driving and gets the same average mpg as Motor Trend got in their long term test of a Chevy1500 crew cab 4-spd4WD with electronictorque control and active fuel management (ie, cutting out cyl). They got 13.9 mpg and I have been averaging 14.0 for first 9000 miles.

The last truck I had was a 1995 Ford F250HD 2WDand its 351 was detunedcompared to F-150 (or Mustang), but in 13 years and139,000 milesI had no engine, transmission, or drivetrainproblems at all.