ekimv65

I have read hundreds of post regarding exhaust upgrades from sounds to best value to cheapest..... The one thing I have noted was most mention that their fuel econ went up by as little as 1/2MPG to 3 MPG. Why would this happen? I understand the basic understanding of an engine being an air pump, more air in plus more air out = efficiency...?

Is it real and why?

Thanks.

lewis26

iTrader: (1)

Where have you noticed that? Never seen that in any posts here from exhaust alone.

Tunes can net you more mpg. not exhaust

il_duce

What are these miracle exhausts you speak of?

Can you post links to some of these hundreds of posts?

No way are people getting 3 MPG, let alone .5 MPG, from a cat back alone. If they are telling you that, they are lying.

Razorback150

What rock have you guys been hiding under? Almost every manufacturer does, or has, made mpg claims about their exhaust. I don't think any of them have been substantiated beyond the claim. And of course you have the butt-dyno effect, which can also cloud mpg results.

I purchased the 4" Heartthrob exhaust because I liked the sound...if it just happened to make good on it's mpg/hp/torque claims then great. My butt-dyno apparently isn't sensitive enough to pick up any real change though.