Header= + or - MPG

[ripper806]

I was just wondering if anybody knows if an aftermarket header will improve, or decrease mpg?

[Lonestar]

....the key to both engine performance and efficiency is moving air. Typically, headers achieve both by maximizing the efficient movement of air (in this case, away from the engine after combustion). The problem is typically emissions, high flow headers tend to result in increased emissions (the more air you move, the more gas you burn, the more emissions you produce) so manufacturers tend to balance performance/mileage with emissions requirements, usually adding things like VVT and fiddling with the computer to compensate for loss of performance.

My own experience with headers is that whatever increase in mileage is lost with the more enthusiastic driving that results.

[aspitaletto]

Originally Posted by Lonestar

My own experience with headers is that whatever increase in mileage is lost with the more enthusiastic driving that results.

yup !

[Slipster17]

Agreed with both the above replies. Although, I did notice the best MPG on my Focus after I had installed the SVT intake and exhaust. It always felt like the Focus engine was stifled in it's stock form. Opening it up made for better/ easier take off from a stop, the engine worked less to stay at speed on the highway, both of which would lead to better economy if you could just drive the car as a normal person and not as an enthusiast

[BondiBlue]

Originally Posted by Lonestar

My own experience with headers is that whatever increase in mileage is lost with the more enthusiastic driving that results.

This.

Nobody gets header(s)/exhaust/intake/etc for hyper-miling. Hyper smiling perhaps.

[ripper806]

Thanks guys. I would no doubt have to give it some throttle love! I only ask because its my daily driver, and I drive 26 miles all highway to work and back. Thank you for the reply's.

[Pennut]

I would think that headers would improve mileage a bit. BUT .... you may void your warranty. Have to be sure which mods will or will not possibly void your warranty.

[dcubed121]

In theory it might help mileage. In practice you will get on it more because it sounds cool.

[FORDSVTPARTS]

It probably would get better mileage but it'll be a LOT louder.

It shouldn't actually "void" your warranty but it can affect the warranty in that they may not be able to diagnose certain issues without the cat in place.

It's also illegal so you should keep that in mind as well since the header will delete the catalytic convertor.

[Captainmorbid]

Unless you get a high flow cat setup. Which likely will void your emissions system warranty anyway, plus it might pop a CEL. And could affect your engine warranty. Don't change things unless you've made your peace with the fact that you'll be on the hook for repair costs.