Help: Mileage Tune Question

[Duramax 6.6L]

I have two truck, 2006 and a 2007, both are identical except for the 2007 has an after market exhaust. I loaded the same tune in both trucks, the 2007 is getting 2 to 3 miles per gallon better while the 2006 truck lost 1 mile per gallon.

Do you think that the exhaust would make make that difference, or does anyone have any ideas on this.

Please move to the right forum.

[N0DIH]

Same driver?

[bballer182]

exhaust can play a big role in mileage.

[Duramax 6.6L]

Yes same driver

[LBZoom]

Yeah exhaust helps a bunch, especially on a tuned truck. You have other variables now like internal temperature in the cylinders and turbo, the ability of the engine to dissipate the heat makes all the difference. Internal heat creates friction and parasitic loss. Hope this helps.