EOE

Someone asked me today, how did you get the exhaust to pop and crackle like that? "Sounds fantastic when you let off the gas." Porsche owner said...

Honestly, I don't know how. What exactly causes this effect on sport cars? Is it the tune, my SuperCharger, or simply my HKS with a test pipe? Because I don't recall it being crackly and vicious when I was NA as I let off the gas.


Can you guys enlighten me?

teamvalorracing

1.rich afr and unburnt fuel igniting in the exhaust system.
2. non-oem decel fuel/ignition map

SRT4's are notorious for that crap.

s2000Junky

Unburnt fuel typically. Can be small exhaust leaks as well. No cat is helpful in creating the environment for this, but isnt solely the reason, just helps allow the unburnt fuel to ignite in the exhaust since there is no cat doing the residual burning. If severe enough it will blow a back fire like a gun shot. That can be timing related as well. But your talking about crackling so its likely excess fuel.

spectacle

Its the combination of having no cats and a slightly rich A/F combusting inside of the exhaust. Anything with a turbo will have hotter exhaust gasses than n/a, which makes the effect that much stronger due to the increase in temperature.

Just speculation.

camuman

p0staboy

Can it affect the motor in any way?

razzele

Mine doesnt do it




http://www.flickr.com/photos/61873555@N06/7245689554/

s2000Junky

If its just crackling, no. If your getting chronic actual backfiring yes, that's not good.

faxter18

Nice pic

FluKy15

My car is NA and does it, mostly just low rpms.