Exhaust Terminology

S

sbottum622

Member
Okay this might sound stupid, but whats the term for like the crackling/popping type sound out of the exhaust when you let off the gas? I know there's a word for it....
 
Pretty sure its backfire.

Wikipedia:
Exhaust system backfires occur in engines that have an emission system malfunction, like an air injection system diverter valve problem, an exhaust leak, or when the catalytic converter has been removed. In some high-performance vehicles, when a driver shifts up and lets off the accelerator, the engine has a moment of running rich. This causes an incomplete burn which causes the fumes to explode in the exhaust system along with an audible pop or bang sound. This is a result of working equipment, and is unlikely to cause damage.
 
I'm surprised by the wiki description; as far as I understood a backfire occured on an incorrectly set up carburettor, when the cylinder literally fires back through the carb rather than through the exhaust?

And the over-run as I understood it was not a period of running rich, but rather a period of running lean.

Open to being corrected on that, but I'm fairly sure I'd understood it right!!
 
Ed Doe said:
I'm surprised by the wiki description; as far as I understood a backfire occured on an incorrectly set up carburettor, when the cylinder literally fires back through the carb rather than through the exhaust?

And the over-run as I understood it was not a period of running rich, but rather a period of running lean.

Open to being corrected on that, but I'm fairly sure I'd understood it right!!
Click to expand...

I could easily be wrong on over-run.... but wikipedia is almost certainly wrong about everything :-)
 
Always thought pops and bangs off throttle was over run caused by a rich mixture.


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tonesgtt said:
Always thought pops and bangs off throttle was over run caused by a rich mixture.


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Click to expand...

Not always. On a less baffled or restricted exhaust there is more hot metal for the tiniest bit of un burnt fuel in the gasses to ignite causing your pops.

If you get flames then yes running rich and very cool.

Better than running lean
 
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