Bottleneck in exhaust system

Kamron Khannakhjavani · July 15, 2016

Just bought a used '07 1500 classic 5.8L. It came with an exhaust system thatstarts at the y pipe. So not full cat back but close. Its 3" pipe to the muffler then i noticed on the outlet of the muffler there is a small section of pipe that is reduced down to 2.5" before increasing back up to 3". Could that be creating efficiency issues or restricting performance?

I had a muffler guy say he wants to go 3" cat to muffler then 2.5" tailpipe to tip but the guys at flowmaster said thats not true it needs to be 3" all the way back.

Question is... Do i drop a few hundred dollars to fix a 4" long bottleneck or just leave ot alone? Im happy with the soind but if i can gain horsepower it may be worth it. Thanks.

kstruckcountry · July 15, 2016

Putting a Flowmaster on would be more restrictive than 2.5" pipe... It's probably not hurting anything, but it's odd that there's just a short section.

Sent from my SM-G920V using Tapatalk

arcasey · July 16, 2016

You aren't loosing enough to justify paying to fix that, unless you do it yourself. Even if you get that fixed I am sure you won't notice the difference and I highly doubt a dyno will notice much either.