LS 376/480 - Backfire Issues?
Thread Starter
Instructor
Joined: Dec 2012
Posts: 155
Likes: 5
From: Illinois
LS 376/480 - Backfire Issues?
I posted this on the C3 Tech Forum, but thought there might be an expert on this Forum that doesn't comment over there --- I have an LS 376/480 crate engine in my 1970 Corvette restomod. The engine runs great, but I'm experiencing a "popping" and "crackling" sound when I decelerate while the car is in gear. Sometimes, I even get one or two "backfire" pops. What is causing this? Can it be tuned out of the engine? The car has a stainless steel Magna-Flow exhaust system that has been installed by a pro, so I know there's no flow obstruction or other problems. Could it be inadequate air intake through the K&N filter setup? Help ...
Le Mans Master
Joined: Feb 2012
Posts: 6,644
Likes: 478
From: OK
Straight exhaust? X pipe? H pipe?
The popping with straight non cat pipes or H pipe is fairly normal... to get rid of it you may need to add cats and an X pipe...
Sorry I got them bass akwards.......
The popping with straight non cat pipes or H pipe is fairly normal... to get rid of it you may need to add cats and an X pipe...
Sorry I got them bass akwards.......
Last edited by 73Corvette; May 30, 2015 at 01:26 PM.
Thread Starter
Instructor
Joined: Dec 2012
Posts: 155
Likes: 5
From: Illinois
Yes, my SS Magna-Flow exhaust has an X pipe section in it and the pro who did it has 40+ years of experience. He's a real craftsman, and is used by all the classic car guys in my area. I have complete confidence that it's not an exhaust leak or flow problem, but didn't know an X pipe could cause this problem. I'll check that out ...
Last edited by Goin70; May 30, 2015 at 12:30 PM.
