Installed my Banks SS Monster exhaust the other day. It sounds awesome, and the huge 5" tip looks mean, but my MPG display shows that I am getting worse mileage. Is this normal? I would think a free flowing exhaust would help with fuel economy. Has anybody else experienced this? Thanks in advance for any comments.

 

you havn't been putting your foot in it to hear the exhaust have you

 

Well of course, now and then, but before at cruising speed the display showed a constant 14.5, now it's at 13.6.

 

wow this is very interesting. i have a 2006 fx4 supercab and i installed a banks power monster exhaust single side exit exactly one week ago. i have a 5.4L and a 3.55 gear ratio (dont know if that has anything to do with it)...but anyway i usually go through one tank of gas per week. during my first week with the exhaust, i only used 1/4 (and yes, that is one quarter) of a tank in ONE week!!
hmm i dont understand your prob..let me know if you have any other questions

 

Same motor same gears, maybe the display is wrong? Before the intake was put on it displayed 14.5 whether in stop and go in town, or out on the highway. The first day after the intake was on, I saw increases up to 2mpg's and then back to 14.5. After wheels and tires same mpg. Now with exhaust it displays less. I don't know how accurate the digital display is.

 

I'd wonder about the dash display.. check your mpg the old fashioned way, top off, drive, top off again.. I put on a Borla SISO a little over 3 weeks ago and my math says I've gained 1.8 mpg on the highway.. I don't see how a straight through exhuast could rob mileage..

 

have you checked the filter on your intake, I know when you buy an aftermarket intake that the filters get dirty really fast, my dad has a 05 f150 4x4 that was strangly getting 13.5 mpg, after cleaning the filter it is around 15.3-15.7 around town

 

I'll give that a try, the filter's been on their for about 9,000 miles. Thanks.