Hey guyz, im new
I have a 2004 f-150 with the 5.4 v8. The 300 hp machine lol. Well I am getting flows put on in two weeks, i am wondering how much it will help my gas mileage, and how much hp gain i will get. Thanks for any replies..

 

you will gain close to nothing with a flowmaster system.

 

do you have any suggestions on which exhaust system to use.... and would they help alot on gas mileage.

 

A lot of people on this forum are happy with the Magnaflow system. You should have gains in hp and torque. As far as gas mileage, I dont think there is much you can do with these trucks to get gains in this area.

 

on my 05 I went with a magnaflow system. I had the flowmasters on my 04 and I did not like them " 40 series", and the flowmaster started to rust after 8 months, just check out magnaflow I think they claim like 11 hp or so, I have a bunch of mods and I get 19 mpg hwy.

I got mine from www.hottexhaust.com with the cupon code fordtruck8

 

Hi.

The term "Flowmaster performance" is an oxymoron... y'know, like "rush hour" .

Here's my well-used, standard answer to your questions:

https://www.f150online.com/forums/sh...=silly+baffles

Call Mike - and just ask him for some advice - it won't cost you anything...

Hope this helps.

Cheers
Grog

 

If you want maximum results from a catback then you will need the a SISO. I have the the Magnaflow 15821 SISO on my 04 and I love it.