22" Magnaflow, Install, and MPG

Last C5 · May 18, 2014

I installed a 22" Magnaflow and made an identicle tow of about 250 miles with the same trailer and weight as before the installation. My MPG went down from about 14.8 to 14.6. Liveable, but not what I expected and I was wondering if anyone else had experienced this.

What we took off

What we added

Why we took off the stock unit

mike94silverado · May 18, 2014

Maybe you're into the gas a bit more because of the sound?.... happened to me lol

Last C5 · May 18, 2014

Maybe you're into the gas a bit more because of the sound?.... happened to me lol

That's a definite "yes" before I started the tow trip.

But I reset the trip thing and used the cruise control for most of the tow trip so that I could make it as equal to the first trip as possible.

kstruckcountry · May 18, 2014

A change of .2 mpg could be caused by temperature, wind, tire pressure. You're really splitting hairs trying to pin that on the muffler. Most notice no real change. Not to mention the mpg on the screen has been known to not be all that accurate.

Last C5 · May 18, 2014

A change of .2 mpg could be caused by temperature, wind, tire pressure. You're really splitting hairs trying to pin that on the muffler. Most notice no real change. Not to mention the mpg on the screen has been known to not be all that accurate.

Yeah, you're probably right and the temperature was very different the two different days. Everything is going so well with this truck I have to find something to obsess about.

kstruckcountry · May 18, 2014

I wouldn't worry about it. It seemed that I picked up about .25 mpg on my 2006, gain on the new ones is even less I bet.

scz71864 · May 18, 2014

the muffler didnt do that. like KS said, there are other factors that came into play with that.

fondupot · May 19, 2014

lol a .2 change in MPG is NOT related to the muffler. Its because you ate an extra donut and you were heavier in the truck.

Bet it sounds good tho

Cliff14Denali · May 20, 2014

Any sound clips? I got the same muffler which I am possibly installing tomorrow.

Last C5 · May 20, 2014

Any sound clips? I got the same muffler which I am possibly installing tomorrow.

No clip, but it's very mellow and not all that loud. At idle you can hear it running now and when you stand on it the rumble is low and authoritive.

Cliff14Denali · May 20, 2014

No clip, but it's very mellow and not all that loud. At idle you can hear it running now and when you stand on it the rumble is low and authoritive.

Good to hear!

Cliff14Denali · May 21, 2014

I had mine installed today and I love it.....nice rumble at idle and not loud on acceleration. All I wanted to do is remove that factory restrictive muffler with something free flow. No bottom end lost and still looks stock.