i went from a bullet performance muffler one in one out to a one in two out flowmaster 40 series and it seems that my gas gauge hits E alot quicker! is this possible or is it just me? Also does having a dumped exhaust on an f150 really take away back pressure?

comments and opinions appreciated!

 

The flowmaster is more restrictive, decrease in low end power, you CAN lose some mpgs at times.

 

If anything that chambered muffler is only holding back 0.5mpg. Straight through is the best to run though.

 

Ya, flowmaster is not your problem here...

 

aight good to hear it!

 

maybe it because the flowmaster isnt as loud and your getting on the gas more? just a thought

 

badd97f150 has a point. if your current setup is any quieter than your last you may be driving a bit harder without realizing it. Coupled with the fact that when you think you are getting worse mileage, your subconsciously gonna cause it to continue by worrying about it. Stop thinking about it and check your mileage in another week or two.