Originally Posted by U RAM
Unless there is a turbo involved those things are a waste of cash.
When you only have a car with a little 2L engine, yea waste of money, does little to no good.
but with a bigger engine like a v8 5.7L, yea it makes a difference. More then you would think. especially if your doing a lot of towing. Ive experienced it with a 4.6L ford 150.