BACK FIRES! Good or bad? please read n help!

[Jonesy_325iS]

when im aproaching a roundabout, or a junction, goin down the gears I get a lovely sounding 'pop pop pop' when i release the clutch. so if im in 4th, clutch in, shift to 3rd, let clutch out, 'pop pop pop' clutch in, shift to second, let clucth out, pop pop pop, clutch in, shift to 1st, clutch out, pop pop pop.

Also happens when i'm goin down a hill in 2nd 3rd or 4th......as the engine is braking i get an almost continous low growling pop pop pop pop pop pop pop pop pop.

Its quite loud, when my mates follow me, they can hear it poping from 5 or six cars behind me! If I drive down my street late at night, just going slow, me mates in houses 2 and 3 streets away text me telling me to keep the noise down coz they can hear the popin!

It sounds really lush, but it is a good thing or a bad thing? is my fuel mixture to rich? I dont seem to have l;ost power, it keeps up fine with my mates phase 2 sport!

Any ideas?

[Jonesy_325iS]

forgot to add its only since I fitted a full powerflow zorst system. one of them straight through things with a jap style 5inch back box..........bought it off Demonbiker off the zone.

[Jonesy_325iS]

oh and one last thing, I wouldnt actually call it a back fire, that might have been the wring word, it doesnt 'BANG', just 'pops'!

and it doesnt happens when im parked up and revin it, and it doesnt happen goin up the gears, just down the gears and engine braking

[Turbo-Brown]

Think it's caused by the weak mixture and retarded ignition on the over-run.

When the exhaust valve opens, the fuel's still burning in there so it 'pops' out.

Pretty sure all engines do it, but that straight through exhausts just amplify (or don't damp out) the sound

[E30BeemerLad]

I get a bit of popping on mine but only at very low revs when engine braking, scorpion system amplifies it quite a bit, you can hear my car streets away.

[fuzzy]

jap style 5 inch tailpipe?...........hmmmmm

[jmc330i]

My 325i Sport did this, but with the really silenced back box you could hardly hear it

So, one hollowed out 325i backbox later with added 3inch tailpipes and all sounded great

No problems with running or lack of power. As long as its only popping (almost like a thumping sound) then I wouldnt worry.

[m-dtech]

its just back preasure mate, dnt worry about it.

bet it sounds sweeeeet

[Jonesy_325iS]

Cheers guys, yeah it does sound sweet, must be bordering on illegal tho.......very very LOUD!

I'll get a sound file linked up soon and let yas hear ya selfs.

And yeah, I know a 5" jap pipe sounds weird lol but it does actually look pretty cool, think its a love or hate thing tho

Cheers

[BrAdZ]

powerblow.....they dont make exhausts with proformance in mind... just looks and sound