Long tube headers MPG with bigger tires

[Matte454]

Yes, my truck is 4.8 with 3.42s and stock 245/75r17

 

[buckshot85]

I don't know about the 4.8 but my 5.3 has long tubes tuned and running 305-55-20 on 20x10 wheels and I only get 15mpg at best. That being said it's mostly city and a heavy foot. With stock rims tune and 33's I saw 18.6 all highway back home after my BB tune

 

[bobkyle2]

Custom tune, Best bang for buck.

 

[Draenor]

Get a tune. With my LT's and staying about 70mph or under I can get 15MPG. Im running a 2500 with the 6.0. Put a trailer on it, 8-10mpg. You just not going to get much more out of it.

 

[66nova]

You can always buy an Autocal so you can change your tune right back to stock before going to the dealer.

You're not going to get anywhere near the full potential out of the CAI or headers without a tune.

 

[GotExhaust.com]

On the highway, at best you could expect little change in MPG. If you have a heavy foot around town you could see a decrease in MPG to the effect of 2-3 MPG. Headers are definitely a worthwhile performance mod, but lower fuel economy is the trade off for sure.

Who knows, maybe we can save you some money on LT's to make up for the loss in MPG?