Hi guys I’m a long time lurker making his second post. I need some of your expert advice. I have a 2011 with the 5.0. As the title says I deleted the stock muffler. While I love the sound I have lost close to 1mpg and definitely some low end torque. I’m torn between either putting the factory muffler back in or going with the 14” Magnaflow. If I choose the latter do you think I will gain my performance/mpg back?
Im not stuck on Magnaflow any better recommendations for just a muffler swap?


Edit

 

Why do you think you lost low end?

 

Less pressure, less torque.

Get a tuner if you want more performance.

 

It definitely lost low end torque. With the stock muffler I could spin the back tires. With no muffler I can no longer do this. It also takes more gas to get up to speed. I don’t want a tuner I just want a nice sound with close to my stock performance. Am wondering if an aftermarket muffler like the Magnaflow 11219 will do this.

 

Seems weird that, all other things being equal, you would feel this kind of difference with something so far down the exhaust line, the muffler isn't the restriction here, it's the cats, which i assume are still in place?

If it's easy to test the stock unit back on the truck, do that, to make sure it's the reason, but it doesn't make sense, even the back-pressure part, for the muffler - anyway, are you sure ambient temps haven't increased? what about tyre pressures? Are you sure it doesn't take more gas to get off the line because you're now noticing and hearing the exhaust earlier now? (placebo?)

 

Agree, the muffler is a straight thru piece, i have it on my garage floor and can take pics if you want

 

I’m aware it’s a straight through muffler. I believe the culprit is the velocity has slowed down. I have read other threads with people experiencing the same issue and I didn’t believe them either lol.... until I cut mine off😞 that is.

I was hoping someone else who experienced this could comment on whether adding the Magnaflow corrected the issues.

 

That's not how exhausts work.

Question has to be whether you've dumped it at the start of the muffler, or if you've replaced the muffler with straight pipe and kept the same overall length.

 

Reset the truck with the muffler removed. You can do so easily by disconnecting the battery negative clamp for no less than 15 mins. That clears the keep alive memory (KAM) and restarts the trucks PCM into learning mode.

 

i cut mine before the muffler but have a straight pipe sitting in the garage. Right now its dumped at my back doors, i plan to have it dump just before the axle