what causes backfiring?

[FiestaR]

on my travels i had a run in with the silver fiesta. dont know the specs of it or which engine its got but from the little run in today i now know that fuckers a beast. i ended up pulling out behind him in the town and he noticed me and wanted to play which was obvious from his moronic actions. the dumb fuck went tearing down the road right in the middle of the town with cars parked and people all over, etc. i wasnt even going to think about going after him because it would have been far too risky with people cars and work being dont to the road. anywho... he caught the light at the bottom of the street and i rolled up behind him and while im sittin there he starts revving like a madman and BOOM. he did this about 3 times. then the light changed and he blasts off and when he goes from first to second BOOM and a ball of fire shoots out the exhaust. ive seen the car around a couple times but never really at WOT, from the exterior modifications i would have thought it would have been more of a showy car but i guess not after that incident.

what i want to know is how this happens, i mean in detail, not unburnt gas in the exhaust gets heated crap. what are the typical mods that set the stage, so to speak, for the car to backfire. i want to know A to get an idea of what hes got under the hood and B just want to know what stuff causes it to happen.

ofcourse i know backfiring doesnt = fast just a little curious since this is only the second car i know if that does backfire and this is the first with a ball of fire out the back. hes obviously got something hiding under the hood since fiestas dont normally travel at warp speeds or backfire not to mention its insanely loud, probably been de-catted ontop of whatevers under the hood.

[Wolf]

Running rich will do it, if it backfired when he shifted, he might have hit the rev limiter (pulls spark when max rpm is reached, so air/fuel isn't ignited, flows into exhaust and combusts).

[FiestaR]

i didnt hear him hit the limiter though. he was also doing this at the light before he took off. im almost posative its a zetec engine (sounded like one) and theres no way in hell an endura-e could ever move that quick. zetecs have a wasted spark maybe this has something to do with it?

i know fiesta, beast and quick normally wouldnt be in the same sentence but this thing hauled ass. i should have my hands full for quite some time. now i really want nitrous... just to own his arrogant ass:haha:

[SLpornSERIES]

I had the same thing happen to me. My car turbo b18 hatch back fires when i hit the check engine light when it runs so rich. At the end of a run where my CEL came on when going back to the pits it backfired so loud it sounded like a shot gun and all the guys staged were looking at me hella crazy.. they asked me if my motor blew. but umm yeah. it happens to me when i run hella rich.:hi:

[Fenrir]

Backfiring > Knocking.

It's usually like that and both problems are at two total ends of the spectrum.

[CoNFuSioUs2002]

my car backfires when shifting sometimes when i shift from 5,500 to 6,000 rpm, no flame comes out but a loud pop, too much fuel for me.

[Fenrir]

Gotta love those stock rich RICH fucking fuel maps in the DSMs. :rolleyes:

As soon as I get on it around 4500RPMs big black clouds of smoke start coming out the back. I guess it's nice to know the fuel pump/injectors are still doing their job...

[FanaticalKilla]

A buddy of mine had a old FB RX-7. Anyways he took the muffler off and figured out how to make it backfire. That thing was louder than a shotgun. Scared the shit out a lot of people.

[CoNFuSioUs2002]

Originally posted by FanaticalKilla
A buddy of mine had a old FB RX-7. Anyways he took the muffler off and figured out how to make it backfire. That thing was louder than a shotgun. Scared the shit out a lot of people. pulling the choke, my friend got one, shit sounds like a gun. Everyfriend i have with a rotary though (about 4 or 5) all backfire, all have no cats, and all are fast as hell for the under 200hp they have.

[bnaka75]

back in hawaii my car poped when shifting but only after i pulled the cats.

[loply]

As I understand(and i may be wrong), on turbo charged cars when you come off the throttle, because of the latency in the turbo there is some compressed mixture which was 'on its way'(to use a non technical word) to be injected and thus has to be vented off somewhere, and it goes into the exhaust via some kind of valvey thing thus igniting.

[FiestaR]

haha fuck you:p

i didnt race him. might help if you read the post first. i might race him eventually but im not in much of a rush to go race (not overly confident ill win haha). seems like this silver fiesta could possibly be the fastest in the city, definately the most modfied (on the outside). im thinkin theres a connection between this guy and his beasty of a fiesta and someone with a beast of an astra, both are loud as fuck and very modified on the outside, again i have no idea whats under the hood. ive seen the astra parked in a little space outside a house and ive seen that fiesta parked there too a couple times. im guessing theyre friends/brothers/roomies or maybe one guy owns both cars?

if i catch him doing that again i will race but im not too sure id win it :( ill definately race him after ive got a few more things under the hood like adjustable fpr, install that piping for colder air into the engine, adjustable pulleys, etc.. or when/if i get a nitrous setup (nothin huge either a 25 or 50 shot).

so back on topic, could the wasted spark in the zetec have something to do with the backfiring? can just de-catting make a car backfire and create a nice little ball of fire? haha im just itchin to find out what hes got under that hood:haha:

[Mr. Import]

yea i know a guy with an old chevy caprise and he'll be driving and he'll rev it up then turn the car off and pump the gass then start it and it booms really loud...we blew the side of the cat out hahaha it was funny we always do it under bridges and stuff and its really loud

[FiestaR]

yea i know that trick. a friend of mine had an old mk2 golf and when he was driving he would turn the car off and back on really quick and itd pop.

this fiesta wasnt being switched on/of tho it was proper backfiring.

[Jhay3]

Originally posted by Import Hater
Proper backfiring? Is that like an oxymoron?

Rob

No, its kinda like doing the wrong thing the right way......

if i catch him doing that again i will race but im not too sure id win it ill definately race him after ive got a few more things under the hood like adjustable fpr, install that piping for colder air into the engine, adjustable pulleys, etc.. or when/if i get a nitrous setup (nothin huge either a 25 or 50 shot).

Well I'm pretty sure will be updated on it on the Kill stories forum whether we like or not. I'll bet it'll be one hell of a race.....:rolleyes:

[T_MO]

Originally posted by Mr. Import
yea i know a guy with an old chevy caprise and he'll be driving and he'll rev it up then turn the car off and pump the gass then start it and it booms really loud...we blew the side of the cat out hahaha it was funny we always do it under bridges and stuff and its really loud
LOL HAHAHAHHAHAHA

all i can think of is the movie ubcle buck!!!!!

thats my favorate movie!!!!
:haha: :haha: :haha: :haha: :haha: :haha:

[FiestaR]

i know all about those flamer kits... he didnt have one. it wasnt a flame out the tailpipe like you get with the old sparkplug trick it was a small explosion/fireball exactly when the it popped.

by proper backfire i meant without hitting the rev limiter, turning the engine off/on, sparkplug in the tailpipe, etc.