Any Performance or MPG Improvement with Flowmaster 817666 system?

[TedH]

As one of my last major purchases from Walmart.com (yes, Walmart) using my now cancelled Associate discount (recent lay-off), I wanted to give my truck a better sound and hopefully performance and gas mileage. No complaints on either but if I can have more, it is good.

 

Anybody have improved mileage with a less restrictive dual exhaust system than the stock, flapper stainless from GM?

 

I purchased the Flowmaster Force II dual #817666. Planning to have local Rainbow Muffler shop install it next Saturday. I plan to keep the stock system in my shop if I ever decide to go quiet again.

 

I note from the Jeg's page that the system can be good for 5-8 hp/tq gains at 4,000rpm on chassis dyno.

 

If i can expect better mileage, that will be great!

[Rkaroll953]

I put an MBRP system on my truck, 3 inch single exit. i dont notice any mileage gains around town but i haven't gone on a highway trip yet. it definitely has a little more go when your in 6th cruising and you roll on the throttle to speed up, thats the only place i noticed more power.

[Jennabear]

Don't buy an exhaust for performance gains....

[fondupot]

You won't notice anything except db levels increasing.