I installed a Banks Cold Air Intake and a 4" G.M. Performance exhaust on my 2005 Duramax (pulling a 12000# 5er). The stock intake draws combustion air from engine compartment, increasing turbo temp and decreasing power. Although I cannot tell any power increase, the engine and tranny temps do return back to normal much quicker than before.
I put the S&B filter kit on my 06 dmax. It's not going to do much if anything for mileage improvement. The only noticeable improvement for me was in throttle response. It did make a noticeable improvement in the turbo lag that's inherent in the dmax. So that and the filter being cleanable and reusable are the only benefits I've noticed. My kit's been on about 5,5 1/2 years now, last year I started getting an intermittent maf error and ces light. I just replaced the filter element and haven't had it since. Point being the element still needs to be replaced after a while.
2006 Silverado 2500hd duramax 4x4 - with a few mods
The stock intake draws combustion air from engine compartment, increasing turbo temp and decreasing power.
I am pretty sure all DMax trucks pull cold air from behind the right front headlight. Some of the older ones I beleive pulled the air in from the right front fender but this was stopped in later years and the hold was plugged with aluminum speed tape from the factory.
2003 Chevrolet C3500, CC, LB, Duramax/Allison
2004 Coachmen Somerset 318RLTS