Exhaust

[Xulfiqar]

What effect does a free flowing exhaust have on gas mileage.

should it increase with a free flowing or vice versa. I am really baffled

I want to know the same thing for header pipes.

[smufguy]

not a lot, but increases up to atleast 2-3 miles per gallon. if u use km and literes, u do the math. gas milage increases with free flow and free flow means, not too many harsh bends and smooth inner piping. and it goes the same for header pipes, the more smoother u push ur exhaust out of the engine without much turbulance, the lesser ur engine has to struggle. So that means longer engine life and higher milage because the engine has to burn little fuel cause everything works smoothly

[Jims 86LXI HB]

Hmm, I think that the theory goes like this. The engine is making a little more power so it should need less throttle to maintain a given speed, hence better gas mileage. But it's not like a exhaust system alone is going to give you a huge increase in power. And, quite frankly if you created a exhaust system that you like to hear, expecially when you rev it up, you tend to get on the gas more. Take a guess what that does you your fuel economy.

I installed my exhaust system before anything else. I noticed a modest increase in power. When I installed my header next, I noticed a big increase in power that seamed to open up the powerband into the higher end (didn't lose any low end), over all all the power gain's made the money feel very well spend.:super: