What causes exhaust "popping"?
03-25-2010, 05:23 PM
#1
Melting Slicks
Thread Starter
What causes exhaust "popping"?
Just out of curiosity, what causes the "popping" noise in exhausts? I imagine it has to do with how the exhaust flows. When I had long tubes and stingers, it would pop all the time during deceleration.
So what is the technical cause of this?
So what is the technical cause of this?
03-25-2010, 05:55 PM
#3
In cars with very quick acting butterflies in the intake (Carb or injected), the driver can be running at a constant or accelerating rpm range. If that driver suddenly lets off the gas the butterfly snaps shot. This ultimately translates into a vacuum in the exhaust manifold/headers. As atmospheric pressure is re-established in the manifold it causes a "poping" sound, much like when you mimick a champaigne-cork being releaed from the bottle by use of your finger against your inner cheek.
Glen
Glen
03-25-2010, 06:43 PM
#4
Melting Slicks
Thread Starter
In cars with very quick acting butterflies in the intake (Carb or injected), the driver can be running at a constant or accelerating rpm range. If that driver suddenly lets off the gas the butterfly snaps shot. This ultimately translates into a vacuum in the exhaust manifold/headers. As atmospheric pressure is re-established in the manifold it causes a "poping" sound, much like when you mimick a champaigne-cork being releaed from the bottle by use of your finger against your inner cheek.
Glen
Glen
03-25-2010, 09:32 PM
#12
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Probably needs a X-Pipe.
03-26-2010, 06:30 PM
#13
As a child of the 60s, I like the sound. It reminds me of the sports cars of that era - usually British, that would frequently "pop" with upshifts. If you get a chance to see film footage of vintage racing you can often hear that sound as well. Maybe it's an acquired preference. I don't know. But I like it.
Glen
Glen
03-26-2010, 11:56 PM
#16
Burning Brakes
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usually only stick cars do that caused most times by lean cond.when decellerating in gear w/motor slowing down the car but if extended decellerating computer shuts off fuel to save cats from damage all pop stops at that time
03-27-2010, 10:33 AM
#19
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St. Jude Donor '03
I looked at my stock 2001 M6 tune (in EFI Live).
OK, it technically is enabled, and DFCO can become active only if all of the following conditions are met:
ECT over 283.9°
RPM over 10,000
MPH over 200
MAP less than 0.0 kPa
Best of luck achieving that combination.
OK, it technically is enabled, and DFCO can become active only if all of the following conditions are met:
ECT over 283.9°
RPM over 10,000
MPH over 200
MAP less than 0.0 kPa
Best of luck achieving that combination.
03-27-2010, 10:29 PM
#20
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Used to be that people did a lot of things to make the car pop on deceleration. If it didn't pop it wasn't any good. A glass pack muffler with the glass blown out of it would really produce a fantastic popping noise. Guaranteed to wake the dead and draw the attention of LEOs.
Bill
Bill