Free Flow Exhaust Questions???

[randyf]

I have a friend that just bought a 2003 Suburban with the 5.3 engine.

It has Flowmaster type dual exhaust system on it.

 

He claims he picked up 2 mile per gallon with the exhaust system.

I find that hard to believe..............if it's true I was thinking about changing my 05 over to something less restrictive.

 

Anyone else whose changed exhaust seen any milage improvements?

[Knowklew]

I have a bridge to sell.....

[mhenshaw]

Big lift and tires help mpg too. Along with bigger cams, superchargers and snow plows.

 

The best mpg is a stock truck with a custom tune for the motor to improve efficiency. Going to smaller tires as well.

[Big Whiskey]

My mileage actually went down when I took my muffler off...cause I love to hear it, lol.

[Rons05z71]

I will let you know over the next couple of fill ups, I just put on a dynomax on my 05. The first fill up I didnt bother because I was listening to it alot. This time I was a little easier though. However it does seem that I have gone more miles this time. (Not a lot) on this tank. I really do think they help in the high RPM range but overall how often are you going to go circle track racing and keep the rpms around 4k? I only did it for the dual out the rear look anyway

[tyhuck]

Performance mufflers + stock engine = lighter wallet and some noise.

 

I have two exhaust setups for my truck that I can change out just by unbolting one and bolting the other in. One is the stock muffler and tailpipe, and the other is a Magnaflow muffler and a 3" single tailpipe. Both setups seem to have the same level of performance (judging by feel since Ive never dynoed the truck) and acheive the same MPG. I had the Magnaflow on for about 8 months nd got consistantly around 14.5 mpg. The stock muffler has been on since deer season started (about 2 months) and Im still getting around 14.5 mpg.

 

Dont get me wrong, I love my Magnaflow, and as soon as deer season is over I will put it back on. But, I bought it with the intention of changing the sound not the fuel mileage. Things like intakes and exhausts may have increased the MPG of the old carburated trucks of the 70s and 80s, and they can help make more power on a high performance engine that makes its power close to redline. But, on a stock pickup, its just truck jewlery and ear candy.

[Chris]

Tell your friend I have ocean front property in Arizona

[Mckenzie]

2 mpg from an exhaust? Maybe on a diesel... But not on a gasser. If anything it will lower it from wanting to hear it run and flooring it at lights to try and turn heads...at least that's what it did to me

[desrtrat]

I have a bridge to sell.....

 

 

[ram1067]

I have a friend that just bought a 2003 Suburban with the 5.3 engine.

It has Flowmaster type dual exhaust system on it.

 

He claims he picked up 2 mile per gallon with the exhaust system.

I find that hard to believe..............if it's true I was thinking about changing my 05 over to something less restrictive.

 

Anyone else whose changed exhaust seen any milage improvements?