Awesome BOV for WRX
10-06-2005, 11:23 PM
#34
VIP Member
Join Date: Nov 2004
Location: Moved to Portland, OR
Posts: 376
Car Info: 2005 Black WRX STI
Originally Posted by Cyrus923
Not the make or model but the individuals car. The hks should never cause the car to backfire. Either should other BOV's that are made well.
Under WOT (wide open throttle) and running with boost, you are pumping a serious amount of air and fuel into the cylinders to give you the power you need. You rev up and shift, at the point that you shift - your BOV vents to atmosphere but you are still drawing a huge amount of air through the MAF, for a split second your ECU gives an proportionate amount of fuel but you just blew off all the air that would have leaned out your mixture to the correct point. End result is a super rich mixture for a split second at shifts. The unburnt fuel travels out of the block into with your exhaust gas, hits the oxygen rich atmosphere (end of the tail pipe) and ignites... tada! Backfire.
Can you avoid this? Yes, recirculate the BOV vent so that the same amount of air goes into the cylinder, you have the right mixture and no backfire.
Why do race cars run with VTA? It give a feeling of better response from your engine and turbo. This is very slight but none-the-less helpful.
So, I hate to you that your wrong but you are and I don't want allot of people out there to have bad information. The fact is that the fastest, most well tuned cars out there (JGTC 300 and 500 cars, Amuse cars, WRC etc) run VTA BOVs that cause backfires. Can you buy a bad BOV, of course - generally if you spend the money, you will get what you pay for.
10-07-2005, 02:16 PM
#35
Registered User
iTrader: (1)
Join Date: Apr 2005
Location: In my TD04 WRX
Posts: 752
Car Info: 2002 WRB WRX
Originally Posted by depdivr
Actually, if the BOV is a VTA (vent to atmosphere) - it absolutely should cause the car to back fire. Unless modified, the BOV is positioned after the MAF (mass air flow sensor). As your turbo pressurizes air, it pulls more air through the intake past your MAF, this air travels from your turbo (now pressurized), to your IC, past the BOV and into your intake manifold. More air = more fuel = more power. Fuel calculations are made by your ECU using the input data from your MAF sensor.
Under WOT (wide open throttle) and running with boost, you are pumping a serious amount of air and fuel into the cylinders to give you the power you need. You rev up and shift, at the point that you shift - your BOV vents to atmosphere but you are still drawing a huge amount of air through the MAF, for a split second your ECU gives an proportionate amount of fuel but you just blew off all the air that would have leaned out your mixture to the correct point. End result is a super rich mixture for a split second at shifts. The unburnt fuel travels out of the block into with your exhaust gas, hits the oxygen rich atmosphere (end of the tail pipe) and ignites... tada! Backfire.
Can you avoid this? Yes, recirculate the BOV vent so that the same amount of air goes into the cylinder, you have the right mixture and no backfire.
Why do race cars run with VTA? It give a feeling of better response from your engine and turbo. This is very slight but none-the-less helpful.
So, I hate to you that your wrong but you are and I don't want allot of people out there to have bad information. The fact is that the fastest, most well tuned cars out there (JGTC 300 and 500 cars, Amuse cars, WRC etc) run VTA BOVs that cause backfires. Can you buy a bad BOV, of course - generally if you spend the money, you will get what you pay for.
Under WOT (wide open throttle) and running with boost, you are pumping a serious amount of air and fuel into the cylinders to give you the power you need. You rev up and shift, at the point that you shift - your BOV vents to atmosphere but you are still drawing a huge amount of air through the MAF, for a split second your ECU gives an proportionate amount of fuel but you just blew off all the air that would have leaned out your mixture to the correct point. End result is a super rich mixture for a split second at shifts. The unburnt fuel travels out of the block into with your exhaust gas, hits the oxygen rich atmosphere (end of the tail pipe) and ignites... tada! Backfire.
Can you avoid this? Yes, recirculate the BOV vent so that the same amount of air goes into the cylinder, you have the right mixture and no backfire.
Why do race cars run with VTA? It give a feeling of better response from your engine and turbo. This is very slight but none-the-less helpful.
So, I hate to you that your wrong but you are and I don't want allot of people out there to have bad information. The fact is that the fastest, most well tuned cars out there (JGTC 300 and 500 cars, Amuse cars, WRC etc) run VTA BOVs that cause backfires. Can you buy a bad BOV, of course - generally if you spend the money, you will get what you pay for.
that right there should be posted on every single BOV thread on this thread!!
12-25-2005, 12:03 PM
#42
VIP Member
Join Date: Nov 2004
Location: Moved to Portland, OR
Posts: 376
Car Info: 2005 Black WRX STI
Originally Posted by SubitunerSTi
I think that should sufice for all you non-BOV believers
Is an aftermarket BOV necessary or desirable on a stock WRX or STI? NO!
Is an aftermarket BoV necessary or desirable on a Stage I WRX or STI? NO!
Is an aftermarket BOV necessary or desirable on a Stage II WRX or STI? NO!
Is an aftermarket BOV necessary or desireable on a Stage IV WRX or STI? YES!
Why sacrifice performance on your WRX or STI before you have to? For more noise? I wouldn't...
01-04-2006, 01:03 AM
#43
Registered User
Join Date: Nov 2005
Location: mililani,hi
Posts: 61
Car Info: 03wrx
got a ssq on mine for a year now and had no problems with anything..only thing is the occasional backfire cause running rich but it sounds pretty cool..scares the shyt out of people wen there next to me..but it never dies out and runs cherry..my friend has 04 sti and bought the greddy bov and his shyt died out,,,backfire and wouldn't idle good..now he bought the ssq and everything is perfect..so if your gonna buy one i would go with the ssq..
02-02-2006, 06:04 PM
#44
Registered User
Join Date: Nov 2005
Location: So Cal
Posts: 85
Car Info: 2005 WRB w/ Silver Rims
yeh.. im gettin my ssqv tomorrw.. lotta friends have it.. not good for the car.. makes u lose a little hp... quoted around 3 by most... im getting it solely for the sound.. and for when i swap my turbo for a Sr50 or SR55....does run rich and probably will backfire... on the stock turbo/ic setup... what im wondering is have any of you who own one had trouble with it damaging your cat(s) or exaust at all?
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