Originally Posted by silverbrick

theoretically long tubes should yield more mileage due to more exhaust flow. just like a muffler and intake BUT longtubes also generally lose low end power which would cause you to lose mileage and any power mod generally makes you want to beat on your truck more and the heavier your foot is, as you know, the worse your mileage gets.

basically, if you stay out of it, you'll get the best mileage and face it, when you bought this truck, and started modding it, you can't honestly say that you bought it and did it for mileage. If you want the most mpg, go buy a Prius.

Originally Posted by SEB

So a Stall & Cam would make me get worse Gas Milage.

Did your Gas Milage change when you intalled the long tubes for the better or worse?

Originally Posted by SEB

Yeah but its almost like trying to mod a car to go fast. Except I want to mod my truck to get good gas milage.

I wonder if I did the Longtubes & a LS6 Cam & some Ported 1.5 TEA Ported 5.3 Heads & a Trailblazer stall would this cause the truck to get worse gas milage.

Originally Posted by jschaff

dood..You are going to always lose mileage when you put on a power adder, FI or cams etc..The stall will make you lose some mileage and there is a difference in efficiency and what you are getting at. With adding heads/cams you are increasing air flow which requires more fuel. Only way to increase mileage is replacing the parts that are parasitic on the engine or one that can be more efficient. LT/CAI/Exhaust.. Comprende?

Originally Posted by RandomHero

Running 93 octane you can up your spark table and gain a **** load of power and gas mileage. I gained almost 3 mpg on the highway going from an 87 octane tune to my 93 octane tune.