popping

[cris88]

any1 know wat exactly causes exuast popping... wen decelarating the car?? car to rich or lean?? as tuff as it can sound at times... is it a bad thing..??

[Bludger]

too rich, fuel igniting in the exhaust.

[cris88]

im guessing its a normal thing since even the properly tuned cars have it,,

[Bludger]

you hear it on the Nissans a lot cos they are tuned rich.

safer rich than lean.

[mrwillz]

u love that sound cris, I always hear u do it at glen.

[cris88]

hhahaha... i dont even do it... cos mine rarely does it... soo tuff!

[TheSaint]

my subaru liberty does it - 2.5ltr boxer engine with 2.5" catback - 2 long resonators and a magnoflow barrel on the end - it was louder when it had a canon on it but the drone was killing me lol

never had the sound from a honda tho

[dvsx]

so thats what it is...

[SHU-ES1]

yo cris, the popping sound i think some people call backfire where the unburnt petrol ignites in your exhaust. just be careful it doesn't shatter your cat.

[bbds]

dw chris its the turbo

[curtis265]

Some people say it's the air rushing back in - what's that.....?

[02gzm]

yo cris, the popping sound i think some people call backfire where the unburnt petrol ignites in your exhaust. just be careful it doesn't shatter your cat.

Backfire is caused from incorrect timing or air/fuel ratio's where incomplete combustion will allow the gasses to flow into the exhaust where they ignite. It sounds nasty but it is the emmisions system doing it's job of burning off the excess fuel.
The popping noise on engine braking is a similar effect with the excess fuel burning off in the exhaust system. This is because the throttle plate is closed and fuel injection is dictated by the O2 sensor which in most cases will be narrowband and thus not 100% accurate.
It's just more noticable in an aftermarket exhaust than a standard exhaust as there is less sound deadening.

Having too advanced timing can also allow the gasses to flow up the intake arm where they will ignite with the fresh air. This is more likely where the damage will be caused.

[TheSaint]

i get it bad in my subaru (EJ25 n/a 2.5ltr efi boxer) ... i thought it was the exhaust gasses from the opposite banks of the boxer engine hitting eachother??