the boost comes from a slightly more precise fuel map than the factory. You are way better off taking that money and having your truck tunned using uprev. they use a dyno to get a fuel map exactly for your truck.
Since every truck as different imperfections in castings and clearances, its impossible for a one size fits all tuner.
there's no long term downside to have a different tune, but there's no way to know for sure that you will gain 2 mpgs from a generic tuner, they often have a decrease.
Since every truck as different imperfections in castings and clearances, its impossible for a one size fits all tuner.
there's no long term downside to have a different tune, but there's no way to know for sure that you will gain 2 mpgs from a generic tuner, they often have a decrease.