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What causes afterfire in an exhaust system? I see some videos online and fire comes out after a rev and letting off the gas. Is this from running cat-less and too rich? Once I get my header will I have to worry about afterfire since I wont have any cats in my car?
 

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You won't have to worry about this no. Most people you see in vids are putting spark plugs in the exhaust to ignite the unburnt fuel. Its purely for show, someone can correct me if I'm wrong but I don't think its a concern on a N/A 2.0 liter engine.
 

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usally a bigger engine can do it...alot of times its only for show, but you can do it without any help...it's just unburnt fuel igniting and being blown out. a 2.0 nor 2.3 wont be able to do it unless maybe jet fuel was used. Also...complete straight pipes help acheve this.

Some people even hook a fuel line to their exhaust and spray fuel in there just for show. Don't try to do this
 

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[quote author=M3i-NTS link=topic=73204.msg1297517#msg1297517 date=1175120784]
I see the afterfire in WRX's all the time.
[/quote]

You can thank the Fast and the Furious movies for that. Any engine expelling enough unburnt fuel can do that, but its not going to happen on your stock motor regardless of your exhaust setup
 

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[quote author=threeforall link=topic=73204.msg1297691#msg1297691 date=1175125656]
try putting a couple of flashlight batteries in your exhaust pipe. what a rush
[/quote]...W H A T ?????? :screwy: :violinbash:
 

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lol.

i think fire in the exhaust pipe would be tight.

i think there may be a kit out there for that.

are we turning this into a rice how-to Since you guys answered the original post?
(not attacking no one)

I for-real would love to have fire in my exhaust. Seriously. I am a kid when it comes to my car.
 

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they do make kits for it, but it's not worth the money. A kid I graduated high school with installed a kit on his 68 mustang and the dumb ass did something...well...dumb, and ended up blowing up his rear end (thats where the fuel cells were located for the kit)
 

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Don't those old mustangs have problem with blowing up when the rear end is hit anyway? Something weird with the placement of their gas tank IIRC.
 

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Yes they make kits for this, no you don't run a fuel line to the exhaust for it. Basically you add a propane tank to your exhaust and a spark plug. The plug is located near the exhaust exit and the heated propane in addition to a bit of free oxygen in your exhaust and the spark plug causes a nice sized flame once the mixture hits the atmosphere with that much free oxygen there. It is extremely ricer.

The flames you see on race cars have NOTHING to do with this. Generally those are from one of two things, you can see them on very low resistance exhausts that are nice and short on race trim vehicles as the short length, large overlap on the cams, and the proper air/fuel trim means that when they lift throttle suddenly instead of the poping sounds you can hear in a free flowing exhaust you actually get fuel burning out the valves and through the exhaust out the exit for a fraction of a second.

Alternately it is caused by an anti-lag system on a turbo charged engine. These systems are NOT found on street vehicles ever. Basically they inject a small amount of fuel between the exhaust ports and the turbine housing which is then ignited. This causes extra pressure in the exhaust before the turbine causing it to spin up much faster, this also causes flames out the tail pipe in most cases. It is also extremely bad for the engine and turbine housing. Of course a race vehicle gets overhauled much more frequently then a road going car does and the turbocharger generally lasts much longer then the engine does anyway on a race vehicle.
-Matt
 

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[quote author=Kodos link=topic=73204.msg1298558#msg1298558 date=1175173368]
Don't those old mustangs have problem with blowing up when the rear end is hit anyway? Something weird with the placement of their gas tank IIRC.
[/quote]

they might...but he was hit...he was blowing flames out when something went wrong....lets just say he had to restore the car again haha

azazel....I never said what type of fuel line had to be ran ;)
 

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[quote author=Kodos link=topic=73204.msg1298558#msg1298558 date=1175173368]
Don't those old mustangs have problem with blowing up when the rear end is hit anyway? Something weird with the placement of their gas tank IIRC.
[/quote].....I think the car you are referring to is the Ford Pinto. One was hit from behind by a tractor-trailer on a freeway and it did explode. Kinda got a bum rap. The new cars today are suppose to be much safer...but I shudder to think what would happen to my Mazda3 if I was rear-ender by a semi> I think it would be good-bye asshole!
 

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my buddies wrx with a turbo back cat-less exhaust does this all the time....

also i knew a guy with a Mk2 golf that had some issue with the fuel levels(or something else)...he could blow a 2 foot flame out of his DTM tip exhaust(those are the ones that bend upright....)
 
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