Exhaust pops and rumbles

[Daniel Young]

I've had Apex motorsports exhaust on my car for a little over a month now and it was my first time ever replacing a exhaust system on an four banger. I was wondering why it pops and rumbles, especially when downshifting from third to secondand from second to first. Is the exhaust creating to much backpressure and could it be harmful. Anyways I kind of like it. sounds cool. And the new exhaust has hampered the msp's performance at all. I hope someone can fill me in.

 

[2K3 MSP]

You're back firing. It's normal when running a catless downpipe. Downshifting, and sometimes just letting off the gas at the right rpm wil cause it to ignite the unburned fuel, causing the popping sound.

 

[Glowmunkey]

You're back firing. It's normal when running a catless downpipe. Downshifting, and sometimes just letting off the gas at the right rpm wil cause it to ignite the unburned fuel, causing the popping sound.

Yeah man, secondary combustion is fun.

 

[kingpin7666]

if its a rough rumble you might need to rotate the 3rd pipe on the exuast (the one before the mufler). Does your mufler touch the bumper??? (see i got this friend who ....... yea yea thats it).