MPG and exhaust?
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More Turbo
Joined: Nov 2004
Posts: 515
Likes: 6
From: Denver, NC
MPG and exhaust?
Ok when I bought my 04 F250 with the 5.4 I was getting 14 mpg on the highway and the truck had some unknown brand of aftermarket exhaust. After the trip I was soooo sick of the low tone that I cut the system out and put the stockwalker exhaust back on. since then the best I get is 9.7 MPG on the highway. Can an exhaust add that much MPG?
FTE Leadership Emeritus
Joined: Sep 2000
Posts: 23,174
Likes: 1,679
From: Stephensville WI
Yes. First, replace the Y-pipe with a free flowing Y pipe. The 04 and older V-8/V-10 Y-pipes have a built in restriction. Also, ask teh muffler shop for a free flowing QUIET muffler. There are a lot of brands.
Your mileage should not have dropped that much with a stock replacement system. This may sound silly, but was the muffler put on backwards? Some mufflers will build up a lot of back pressure if installed backwards.
Check the rest of the install to see if it looks OK. It sure sounds like they introduced some blockage with the new system.
Your mileage should not have dropped that much with a stock replacement system. This may sound silly, but was the muffler put on backwards? Some mufflers will build up a lot of back pressure if installed backwards.
Check the rest of the install to see if it looks OK. It sure sounds like they introduced some blockage with the new system.
Hotshot
Joined: Mar 2007
Posts: 10,101
Likes: 40
From: Pa
A stock exhaust vs an aftermarket freer flowing exhaust isn't going to affect mpg much if at all. You might have gotten into a headwind or crosswind, combined with winter blend fuel, that will make your mpg go in the toilet fast.
If you want a freer flowing muffler than stock with a very close to stock sound look at the Flowmaster 70BB2 or Flowmaster 50BB mufflers. A large 28"-36" case magnaflow oval muffler will also yield a close to stock sound.
If you want a freer flowing muffler than stock with a very close to stock sound look at the Flowmaster 70BB2 or Flowmaster 50BB mufflers. A large 28"-36" case magnaflow oval muffler will also yield a close to stock sound.
