Exhaust popping
#1
05-03-2008, 10:19 PM
Exhaust popping
I have a problem I just cant seem to figure out. The engine is a basic 350 with vortec heads and afterburner headers when you let off the gas it pops through the openheaders . Ive had three cams in it and three different carbs no difference. At the end of the run its like fire crackers going off the engine runs well for what it is but the popping is annoying. Ive changed the plugs and installed the aluminum header gaskets it is still the same. The only way I can get rid of it was to put header mufflers on it I am at a loss.....any ideas?
#2
05-03-2008, 11:48 PM
RE: Exhaust popping
I have the same problem...and was told what that is..and forgot.... but don't get header mufflers, I think it's due to there being no back pressure..........you mean the pop corn sound?
#3
05-04-2008, 12:47 AM
RE: Exhaust popping
this should help you guys out a little
and yes, i realize that it says "riders" in there, i found this info on a motorcycle forum. but it's the same basic principles for a caar engine.
Burn Baby Burn
The last thing I want to address today is the subject of deceleration backfire, or “poppingâ€. This topic generates a lot of concern from inexperienced riders, or even from experienced guys who just hate the noise, so lets take a look at what causes it. But first things first, lets define the issue:
Deceleration Backfire is caused by fuel burning in the exhaust manifold or header.
No ifs ands or buts, that’s what causes it. But the bigger question is how does gas get there in the first place, and that’s a bit more complicated. Generally, there are a variety of ways it gets there, and a variety of things that can make the backfiring worse. But there’s a kicker, and something you should understand before we go any farther:
A motor in perfect tune will exhibit deceleration backfiring.
Therefore, just because your motor is banging it up, doesn’t mean there’s anything wrong. And consequently:
Getting rid of the noise means de-tuning your motor.
The last thing I want to address today is the subject of deceleration backfire, or “poppingâ€. This topic generates a lot of concern from inexperienced riders, or even from experienced guys who just hate the noise, so lets take a look at what causes it. But first things first, lets define the issue:
Deceleration Backfire is caused by fuel burning in the exhaust manifold or header.
No ifs ands or buts, that’s what causes it. But the bigger question is how does gas get there in the first place, and that’s a bit more complicated. Generally, there are a variety of ways it gets there, and a variety of things that can make the backfiring worse. But there’s a kicker, and something you should understand before we go any farther:
A motor in perfect tune will exhibit deceleration backfiring.
Therefore, just because your motor is banging it up, doesn’t mean there’s anything wrong. And consequently:
Getting rid of the noise means de-tuning your motor.
#4
05-04-2008, 01:43 AM
Join Date: Oct 2007
Location: The 'Burbs of Chicago
Posts: 18,306
RE: Exhaust popping
As the saying goes, "they all do that". There's nothing wrong with your engine. Most hotrodders or racers like that noise, it sounds more......manly!!!
#5
05-04-2008, 07:29 AM
RE: Exhaust popping
It does seem to be running a little bit rich, I inspected the old header gaskets and can find a few places where they might have been leaking which would give air to the unburnt fuel. I noticed the headers dont seem to match up real well with the gaskets I am not overly thrilled with the flowtech afterburner headers... After today I am going to pull off the aluminum header gaskets and see if they are sealing ok. The few guys I asked at the track say its nothing to worry about but it is the only car that seems to do it...
#6
05-04-2008, 10:23 AM
Join Date: Oct 2007
Location: The 'Burbs of Chicago
Posts: 18,306
RE: Exhaust popping
I took out my rusty old plain headers and put the ceramic coated Afterburner headers in mine, I like them. I don't know if I would notice much of a difference if I were to gasket match the headers. For a street car, I did't feel it was worth the effort. Unless your gaskets are leaking, I would leave it alone. That's not the source of your rapping anyway, it's a natural phenomenon. Are you using Percy's "Seal-4-Good" gaskets? I swear by 'em.
#7
05-04-2008, 09:25 PM
RE: Exhaust popping
It has the percy gaskets on it. The car was running decent today but it was hard to be consistant after the sun started to heat up the track up some its an 1/8th mile we ran a 8.46, 8.46, 8.42, 8.52(spinning) and a 8.34. It only has a .440 lift cam in it and stock shortblock I am going to rejet the carb and play around with a few other things I think it could get in the 8.0s with some better tuning and I need to get the line lock installed. I am going just to ignore the poppingwe have another engine to install when I get the time.
#9
05-05-2008, 07:28 PM
RE: Exhaust popping
It bangs and pops about 5 or 6times till I hit neutral its faily loud it also does it when you rev it up in neutral and let off. It will shoot a flame out the headerabout 8 inches or so when it pops.
