got a new bov...and now my car shoots rediculously large flames...
08-28-03, 04:44 PM
#1
got a new bov...and now my car shoots rediculously large flames...
What's the deal? Now that i installed my A'pexi bov, my car will shoot huge flames. All i have to do is be in any gear and boost just a little bit...hear the bov go off...a second later...BAM! I don't have a problem with it by all
...but would like to know how the bov is making it shoot flames now?
...but would like to know how the bov is making it shoot flames now?
08-28-03, 04:57 PM
#3
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I had the same problem with my RFL. I put the stocker back on until my S-AFC comes. I have a S4 and was planning on hooking the throttle input to the pressure sensor. If I leaned out my low throttle map, would this fix the fireballs? Any bad side effects I'm not thinking about?
I figure my vacuum at idle is considerably lower than the instant when I let off the boost. So if I leaned out the extreme vacuum I would get rid of my flame thrower? Anyone done this with success?
I figure my vacuum at idle is considerably lower than the instant when I let off the boost. So if I leaned out the extreme vacuum I would get rid of my flame thrower? Anyone done this with success?
08-28-03, 05:21 PM
#4
RX-7 Bad Ass
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Shoot, it's way fun having fireballs! That isn't something you need to fix!
If your car is doing it BIGTIME, you've got other problems - worn spark plugs, worn engine, something.
Dale
That isn't something you need to fix! If your car is doing it BIGTIME, you've got other problems - worn spark plugs, worn engine, something.
Dale
08-28-03, 05:51 PM
#5
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Exactly, it's just the ECU over compensating the mixture on deceleration, assuming that the excess air dumped by the BOV is being replumbed into the intake, so it's already metered it, thus it thinks there's more air than there really is, which gives you excess gas, and, hello flames!
08-28-03, 06:01 PM
#6
I have a feeling that aftermarket BOV's can cause more problems.. I modded my stock BOV (and plumbed to open air) and the metered air being dumped can cause problems.. shifting isn't the only time your BOV is open.. it's open any time your turbo is producing significantly more boost than your engine is taking in.. E.G. high RPM cruise conditions... it dumps the air, ECU adds fuel for that air, engien runs rich, fuel economy goes downhill quickly, plug life goes downhill quickly, turbo gets hot due to all of the fuel, etc...
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08-28-03, 06:20 PM
#9
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The BOV shouldn't open, the same amount of force should be pressing from the backside, as from the turbo side, plus the spring rate, which should hold it closed under boost.
08-28-03, 09:06 PM
#11
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Originally posted by Terrh
E.G. high RPM cruise conditions...
E.G. high RPM cruise conditions...
08-28-03, 10:31 PM
#14
OH,YOU TOUCHED MY TRALALA
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hehe now i want my bov. i shot a flame at a guy in a honda the other day that was ridding my ***. i was in 2nd and going from 6 to 8 grand and then POW!!! and he hit the breaks fast!!! it was great. and thats with the stocker vented open. hehe 
ej
ej
08-29-03, 12:05 AM
#15
I'm bastardizing my car!
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i wonder if its beneficial to have a little extra gas come in off throttle. This is why. I know that baja racers when going cross country let off the throttle for a second and get some extra fuel, unburnt though the engine. This is supose to help keep the engine cool. it only turns to fire when it hits the exhaust.
08-29-03, 01:17 AM
#17
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I have a Thunder Fabrications 3" DP/MP, Corksport Single 3" Catback, and the stock BOV, and I shoot 2' flames when shifting gears at WOT from what I hear. I can swear that I'm also going deaf in my left ear from the damn CS exhaust.
08-29-03, 06:47 AM
#18
Thats not an FC...
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you guys are funny...
the only BOV i know of that opens in reaction to a pressure differential is the HK$ SSQV, and that would be the mini-valve that opens and then the main/large valve open when the vaccum is high enough.
the Boost will hold the valve closed, if its a Pull type, like a Greddy Type S or others. the boost goes in thru the vaccum signal hose and presses on the backside of the valve and holds it closed, as previously mentioned, but there is also boost inside the IC pipes which is pushing back... so its about the same force and they cancel eachother out, and what force is left being applied to the valve is the internal spring.
the valve opens when the vaccum signal is high enough to overcome the spring pressure forcing the valve closed. Usually, the BOV is supposed to be tuned so that the only vaccum strong enough to force the vavle open, is the vaccum created during shifting/deceleration while in gear. So, if you pully 18 in/hg while idling, you want the BOV to be closed. and when you shift or let off the gas while in gear, your vaccum would jump to 20 in/hg or so... THATS the only time the BOV should open... not when you boost is 20 psi, or when its 1 psi or when your RPMs are 6000...
So, when the BOV opens and is vented to atmosphere, it releases metered air; air that your MAF has counted. When the air that has been counted by the MAF and ends up being released by the BOV... the ECU injects the "proper" amount of fuel, or what it Thinks is the proper amount. If you have 30 units of air counted and on its way to the engine and the ECU is programmed to supply 4 units of fuel... what happens if 15 units of that 30 units of air "magically" disappears? the ECU still adds the 4 units of fuel which is now too much for the 15 units of air that actualy made it to the engine... Voila! Fireballs... thats what happens on ANY car w/ a AFM-based intake system. the only way to get around that is with a MAP/SPeed density system (Hondas and VPC's, for example).
the Fireballs that come from WRC rally cars is actually from an Anti-Lag system. there is an additional injector plumbed right into the exhast manifold. When ever the driver lifts off the throttle, the injector fires extra fuel into the exhaust and explodes due to the sheer heat. this explosion keeps the turbine wheel spinning super-duper fast even when the throttle is closed... that way when the driver gets back on the throttle, the turbo is all ready to hit full boost; no turbo lag between shifts. Hence, "Anti-Lag". the only problem is... you need a new turbo after every event... at the very least, a new turbine wheel. Explosions occuring right on the turbine blades are not conducive to long turbo life
oh, and excessive richness will lower your EGT's as TurboIIRude dude said.
the only BOV i know of that opens in reaction to a pressure differential is the HK$ SSQV, and that would be the mini-valve that opens and then the main/large valve open when the vaccum is high enough.
the Boost will hold the valve closed, if its a Pull type, like a Greddy Type S or others. the boost goes in thru the vaccum signal hose and presses on the backside of the valve and holds it closed, as previously mentioned, but there is also boost inside the IC pipes which is pushing back... so its about the same force and they cancel eachother out, and what force is left being applied to the valve is the internal spring.
the valve opens when the vaccum signal is high enough to overcome the spring pressure forcing the valve closed. Usually, the BOV is supposed to be tuned so that the only vaccum strong enough to force the vavle open, is the vaccum created during shifting/deceleration while in gear. So, if you pully 18 in/hg while idling, you want the BOV to be closed. and when you shift or let off the gas while in gear, your vaccum would jump to 20 in/hg or so... THATS the only time the BOV should open... not when you boost is 20 psi, or when its 1 psi or when your RPMs are 6000...
So, when the BOV opens and is vented to atmosphere, it releases metered air; air that your MAF has counted. When the air that has been counted by the MAF and ends up being released by the BOV... the ECU injects the "proper" amount of fuel, or what it Thinks is the proper amount. If you have 30 units of air counted and on its way to the engine and the ECU is programmed to supply 4 units of fuel... what happens if 15 units of that 30 units of air "magically" disappears? the ECU still adds the 4 units of fuel which is now too much for the 15 units of air that actualy made it to the engine... Voila! Fireballs... thats what happens on ANY car w/ a AFM-based intake system. the only way to get around that is with a MAP/SPeed density system (Hondas and VPC's, for example).
the Fireballs that come from WRC rally cars is actually from an Anti-Lag system. there is an additional injector plumbed right into the exhast manifold. When ever the driver lifts off the throttle, the injector fires extra fuel into the exhaust and explodes due to the sheer heat. this explosion keeps the turbine wheel spinning super-duper fast even when the throttle is closed... that way when the driver gets back on the throttle, the turbo is all ready to hit full boost; no turbo lag between shifts. Hence, "Anti-Lag". the only problem is... you need a new turbo after every event... at the very least, a new turbine wheel. Explosions occuring right on the turbine blades are not conducive to long turbo life
oh, and excessive richness will lower your EGT's as TurboIIRude dude said.
08-29-03, 09:17 AM
#19
well then what made my turbo glow bright orange? huh?
excessive richness DOES lower EGT's... to a point.. when enough unburnt gasoline is getting into the exhaust to ignite there.. EGT's climb...
and I can HEAR my BOV venting air at 140-150kph + light throttle.. and when my TPS was screwed up and my car was idling at 3500RPM... I could watch/see/feel/hear the hurricane coming out of the BOV... So yeah, I know, if you take it easy to redline you don't see much boost.. but clearly the turbo spools, at least partially..
excessive richness DOES lower EGT's... to a point.. when enough unburnt gasoline is getting into the exhaust to ignite there.. EGT's climb...
and I can HEAR my BOV venting air at 140-150kph + light throttle.. and when my TPS was screwed up and my car was idling at 3500RPM... I could watch/see/feel/hear the hurricane coming out of the BOV... So yeah, I know, if you take it easy to redline you don't see much boost.. but clearly the turbo spools, at least partially..
