Exhaust backfiring?!

[LAZZEE RARSE]

Call me a noob im not assed.

But on my way home from work i saw another veccy burn passed me. As i caught it up at the traffic lights, it started reved its engine and the exhaust started backfiring.

Seen this before on tv and other highly tuned cars.

But got me wondering how do you get your echaust to backfire. And why does it backfire??

[John LE]

Backfiring is caused by unburnt fuel igniting in the exhaust normally

[keefy*2010]

Call me a noob im not assed.

But on my way home from work i saw another veccy burn passed me. As i caught it up at the traffic lights, it started reved its engine and the exhaust started backfiring.

Seen this before on tv and other highly tuned cars.

But got me wondering how do you get your echaust to backfire. And why does it backfire??

Must have been petrol head and able to adjust the electronic timing or perhaps they turn ignition off momentarily, mainly boy racers around here do it

[Grumpy1954]

It's possible to advance/retard (can't remember which) the timing to make it backfire, but John likely got the reason in this case.

[rushy]

De cat.......or flamer kit.

[Das]

or flamer kit.

I go with that, it would be difficult to get a "normal" car to do that these days due to the lambda sensors and the cat. Used to be able to get my MKII escort to do teh popping and banging on over run years ago, that was fun.

[LAZZEE RARSE]

Fail mot if you decat exhaust though dont it?

[John LE]

Not if you re-fit it before the MOT

[rushy]

Fail mot if you decat exhaust though dont it?

You can get a de cat pipe made so you just bolt the cat back in when needed, although on more modern petrol's you need to play the the management as well so the EML doesn't come on and put you into limp.

[sxi-dean]

My 3.0 V6 406 coupe used to pop following heavy accelaration and then subsequent quick lift off. Only did it after I had a stainless system fitted though, and it sounded great!