Subaru Impreza wrx popping sound

ckendrick

Hi, i own a 2002 wrx, just recently sometimes when i change gear from 1st into 2nd and sometimes 2nd into 3rd it makes a popping sound from the exhaust, it doesnt happen all the time only now and again, it seems to do it when i take my foot off the accelerator to change gear. i recently fitted a cold air induction kit and was wondering if enough air was getting to it and if this would be the problem. any help is much appreciated.

ateixeira

Do you have a stock exhaust? Some times the aftermarket ones tend to do that.

ckendrick

Am not to sure, i know its been de catted and it has an aftermarket exhaust

ateixeira

Makes sense...the catalytic converter's job is to heat up and burn any unburned fuel in the exhaust stream so that it doesn't pollute.

If the cat is removed, such fuel could burn as it exits the exhaust tip and create that poppping sound.

The car might fail emissions tests, too.

turnten

Completely normal for a WRX with exhaust mods to have a little popping and gurgling. Rare, but it can even spit a small flame out the exhaust under certain conditions. If you have a blow off valve that vents to atmosphere, this is even more likely.

ckendrick

Thanks for your replies, i was hoping it was nothing bad, i did fit a blow off valve at the same time as the induction kit so that is probably it, it has had a mot since the de cat, previous owner spent a fair few quid on a remap after the exhaust was done.

turnten

If you can, recirculate you BOV. Cars equipped with an air flow meter are not designed to have a BOV vented to atmosphere. It causes a momentary extreme rich situation which is where your pop, and likely a flame, is coming from. If you have an intake system, you will still hear the audible "pssshhhh" even when recirculated.