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Old 11-15-2001, 02:21 PM   #1
RS_NW
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Default Spark Plug In Exhaust

I've watched some footage of some rally cars and noticed when they are off throttle they have a loud popping noise comming from a spark plug that ignites the unburnt fuel in the exhuast to keep the turbo spooled up.

Not that I would try this, but just out of curiousity, would it be possible to accomplish this with a otherwise NA car? Could this be accomplished with a otherwise stock car? There would obviously be no performance out of it just that cool rally car pop off throttle.
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Old 11-15-2001, 02:26 PM   #2
bsquare
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There are 2 different things going on here: the Anti-Lag System which is igniting unburnt fuel in front of the turbo to keep it spooled and the normal noises certain cars make when you come off the throttle. You can't do the former on an NA car, but you can get the latter with some headers and a Scoobysport exhaust. Pop pop pop growl!


Ben
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Old 11-15-2001, 05:23 PM   #3
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The popping noise you here is the anit-lag system. It is not unburned fuel ignited by a spark plug in thexhaust. When in use, the anit-lag system severly retards the ignition timing during off throttle applications to the point that the fuel mixture is still burning quite healthy when it exits the chamber. The still burning air/fuel charge keeps the turbo spooled up. Anything is possiable so I guess you could do it on a N/A car... but there would be no point. Since there is no turbo to spool, you would be retarding ignition timing for nothing. It would be precevied by most as a backfire... and people associate backfires with a poorly running car. Just ask my girlfriend... she hates the fact my Stromung pops when I shift. Says it makes my car sould like its farting. Go figure.
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Old 11-15-2001, 05:37 PM   #4
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You learn something new everyday. My girlfriend hates how my car pops in shifts too.
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Old 11-16-2001, 03:14 AM   #5
ashtaron14
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One of my friend owns a Supra, the newer one, after the squared one...

Anyways... he had a job working as a delivery boy for Domino's pizza... so he tuned his car for the job... hehe... He would have to put in new spark plugs every week because they would get blown from the engine and goes into the exhaust, and launched out of the car... He would see people behind him from the rear-view mirror trying to dodge whatever they thought it was...so while delivering he could suddenly lose a piston or two... eventually he lost the job because of the noise that his car makes and the speed that he drives... he said it was still his best experience/fun he has ever had... and I would believe him
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Old 11-16-2001, 03:52 AM   #6
Keiho
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Mmkay...doesn't sound very safe or plausible...but...cool nonetheless.
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Old 11-16-2001, 02:38 PM   #7
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How would a spark plug get shot through the muffler?!

-justin
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Old 11-16-2001, 03:15 PM   #8
scotty305
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The popping sound comes from unburnt fuel being ignited, I'm not sure if it's from a spark plug or if it can also be caused by a eiseling effect (hot unburnt fuel reaches a source of air/oxygen and ignites).

Cars sold to the general public have many features to prevent unburnt fuel from leaving the exhaust pipe, including EGR (exhaust gas recirculation) valves, catalytic converters, and probably a couple other things that I can't recall offhand. they do this for a couple reasons: fuel economy and environmental concerns.

You'd probably be better off to keep it that way. That popping sounds cool, but do are you really willing to sacrifice mileage or fail a smog test, just so that your car can sound like a rallycar?

After installing aftermarket exhaust and headers, some people get this popping sound, it ususaly comes from unburnt fuel reaching the catalytic converter and igniting. If you were to run your car with a free-flowing, cat-less exhaust system, you might shoot flames out the tailpipe when you shift.

-scott-
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Old 11-16-2001, 03:27 PM   #9
RS_NW
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I never said that I wanted to to do this.
Quote:
Not that I would try this, but just out of curiousity
It's from my first post.
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Old 11-16-2001, 05:20 PM   #10
Blindeye_03
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Quote:
Originally posted by scotty305
The popping sound comes from unburnt fuel being ignited, I'm not sure if it's from a spark plug or if it can also be caused by a eiseling effect (hot unburnt fuel reaches a source of air/oxygen and ignites).

Cars sold to the general public have many features to prevent unburnt fuel from leaving the exhaust pipe, including EGR (exhaust gas recirculation) valves, catalytic converters, and probably a couple other things that I can't recall offhand. they do this for a couple reasons: fuel economy and environmental concerns.

You'd probably be better off to keep it that way. That popping sounds cool, but do are you really willing to sacrifice mileage or fail a smog test, just so that your car can sound like a rallycar?

After installing aftermarket exhaust and headers, some people get this popping sound, it ususaly comes from unburnt fuel reaching the catalytic converter and igniting. If you were to run your car with a free-flowing, cat-less exhaust system, you might shoot flames out the tailpipe when you shift.

-scott-

I have seen flames coming out the tail pipe of my friends '97 supra tt, granted he has a catless downpipe, and a 3.5" catback & apexi N1 canister.

About the EGR: the phase2 block imprezas (my01 type) dont have the EGR (per subarumastertech on the board).

-justin
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Old 11-17-2001, 02:33 AM   #11
joltdudeuc
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rally car: no cats, str8 though pipe... it is backfire, that's the popping noise... basically, as the ignited fuel (which is kinda in a gas form) reaches the end of the pipe, the air hits and allows a complete burn...

this happens when you got not cats, and when you got huge compression (like a turbo)... Alex, out club president, could do it for a little while... when he'd shift from 1-2 and 2-3 he'd send a sonic boom with a little fireball out that back... nice... and loud... further tuning has now elminated that... now he has a nice sound with puffy white smoke comnig out in small, small spurts...

i doubt it's possible on a NA car...

besides, it's "pull me over" stuff... and here in Union City, that's a no no... just ask Brucelee how the cops are here

-Gagan
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