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Joined: Dec 2004
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Senior Member 2003 Toyota Celica GT
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Senior Member
2003 Toyota Celica GT
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Ok, I know they sound sweet, and that you need a turbo for it, but do they acutally serve a functional purpose?
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Joined: Jan 2004
Posts: 311
Member 2000 Toyota Celica
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Member
2000 Toyota Celica
Joined: Jan 2004
Posts: 311 |
Most everything in life serves a purpose.
"I didnt realize girls had that much plumbing down there. I saw a diagram of it and it looked like a map for six flags."
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Joined: Aug 2003
Posts: 399
Member 2000 Toyota Celica
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Member
2000 Toyota Celica
Joined: Aug 2003
Posts: 399 |
i'm no turbo expert but i believe blow off valve is same thing as wastegate, i will stand corrected if i am wrong but read this. http://auto.howstuffworks.com/turbo6.htm
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Joined: Sep 2003
Posts: 315 Likes: 1
Ex-Ricer 2001 Toyota Celica
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Ex-Ricer
2001 Toyota Celica
Joined: Sep 2003
Posts: 315 Likes: 1 |
^yes. wastegate recycles, atmospheric blow off valve dumps it (making the noise everyone creams their pants over), and there are hybrid ones that will recirculate some and discharge the rest.
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Joined: Oct 2004
Posts: 368
GT4 1990 Toyota Alltrac
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GT4
1990 Toyota Alltrac
Joined: Oct 2004
Posts: 368 |
it is sort of like a wastegate... it lets off excess exhaust... that's what the 'pshhhhhhhhhhhhhh' is, lol. in n/a cars... you want back pressure... in turbo you want NO backpressure... that's why you get a 3'' exhaust. and the BOV lets off more excess exhaust
90 all trac 98k miles... *To be resurrected...* Gives new meaning to "It looks fast"...It IS fast '90 rolla "Lunchbox on wheels" 167k strong!
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Metal Storm 2040 2000 Toyota Celica
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Metal Storm 2040
2000 Toyota Celica
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kills un-needed "waste pressure" from the turbine
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Joined: Jun 2004
Posts: 262
Member 1993 Toyota Celica Alltrac
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Member
1993 Toyota Celica Alltrac
Joined: Jun 2004
Posts: 262 |
BOV is on intake side. It has nothing to do with exhaust. It vents out the air to prevent compressor surge due to the throttle is slammed shut when you shift.
Bypass valve works the same way as BOV. The only different is it recirculates the air back into the intake (before the compressor wheel) Bypass valve is common to car that come with AFM or MAF (non-MAP type or non-speed density air measuring system) This is to prevent venting metered air out. If the metered air is vented out too much, the car will run too rich and may stall.
On the other hand, wastegate lets the "exhaust" bypasses the turbine wheel. The main purpose of the wastegate is "to limit boost" So, the wastegate is more like boost controller than the BOV or BPV.
By the way, BOV, bypass valve and wastegate will not work on N/A car.
93 ST185, 91 ST185 (sold), 99 Solara SEV6 Boston
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Member 2004 Toyota Celica
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Member
2004 Toyota Celica
Joined: Apr 2004
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The bov release presure from the compressor when you let off the throttle. If the presure is held in the air presure can get to high and break the shaft connecting the compressor and the turbine, bov also helps get rid of turbo lag by letting the turbo freewheel in between shifts.
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Member 1993 Toyota Celica Alltrac
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Member
1993 Toyota Celica Alltrac
Joined: Jun 2004
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the air presure can get to high and break the shaft connecting the compressor and the turbine Nah...Not that bad. It just shortens life of the turbo, but not breaking the shaft. The pressure will not get too high due to the throttle is shut and there is not enough air in to the cylinder, so there is no enough exhaust velocity to spin the turbine and compress more air in. It's just the compressor surge at the wheel that is not good. When the wheel spins at 100,000 or more rpm, coming to hault instantly is not a good idea.
93 ST185, 91 ST185 (sold), 99 Solara SEV6 Boston
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Senior Member 2002 Toyota Celica GT
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2002 Toyota Celica GT
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Senior Member 2003 Toyota Celica GT
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2003 Toyota Celica GT
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Just out of curiosity, which is best: BOV, bypass valve, or wastegate?
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Joined: Jun 2004
Posts: 262
Member 1993 Toyota Celica Alltrac
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Member
1993 Toyota Celica Alltrac
Joined: Jun 2004
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Just out of curiosity, which is best: BOV, bypass valve, or wastegate? Read my post up there. BOV and wastegate are two different things. They do different jobs. You cannot compare them.
93 ST185, 91 ST185 (sold), 99 Solara SEV6 Boston
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Member 2000 Toyota Celica
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2000 Toyota Celica
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nice info gt4, i stand corrected. Just for clarification boost is limited at the wastegate correct?
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Member 1993 Toyota Celica Alltrac
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Member
1993 Toyota Celica Alltrac
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Yup.. boost is limited at the wastegate. It does that via the wastegate actuator. If the boost pressure on the actuator diaphram exceeds the wastegate spring setting, it open up the wastegate door and let the exhaust gas bypasses the turbine. Unlike the wastegate, BOV act on "vacuum" If it senses the vacuum (due to throttle shuts), it opens up and releases the compressed air out. Let me add more info on aftermarket boost controller. Aftermarket boost controller (manual or electronics one) allows you to boost more than stock wastegate setting by manipulating the boost pressure signal to the wastgate actuator. The actuator will not sense the real boost pressure. Hence, the wastegate door is kept shut longer and the turbo builds up more boost. (up until you hit the desired boost set by boost controller)
93 ST185, 91 ST185 (sold), 99 Solara SEV6 Boston
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Member 2000 Toyota Celica
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2000 Toyota Celica
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Specialist 2002 Toyota Celica
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Specialist
2002 Toyota Celica
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just a question: if the turbo car is in park and you rev the engine would you hear the blow off valve go off or does the car have to actually be moving? might sound dumb but ive never experienced a turbo car yet.
respect the gt-s
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Joined: Jun 2004
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Member 1993 Toyota Celica Alltrac
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1993 Toyota Celica Alltrac
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just a question: if the turbo car is in park and you rev the engine would you hear the blow off valve go off or does the car have to actually be moving? might sound dumb but ive never experienced a turbo car yet. Some yes, some no. For example, on alltrac, I can let off BOV if I rev the engine high enough. But it'll not be as loud as when engine is under load and boost.
93 ST185, 91 ST185 (sold), 99 Solara SEV6 Boston
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Specialist 2002 Toyota Celica
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Specialist
2002 Toyota Celica
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thats cool i was just wondering i hope i can hear mine if i just wanted to show it off sometime
respect the gt-s
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seabass 2000 Toyota Celica GTS
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seabass
2000 Toyota Celica GTS
Joined: Jan 2004
Posts: 873 |
it is sort of like a wastegate... it lets off excess exhaust... that's what the 'pshhhhhhhhhhhhhh' is, lol. in n/a cars... you want back pressure... in turbo you want NO backpressure... that's why you get a 3'' exhaust. and the BOV lets off more excess exhaust eek not the backpressure demon again only reason you can't do a 3 inch exhaust on are na 4cyls is because of heat the air in the exhaust will get too cold cold ai is denser there for flos slower a 2.25/2.5 exhaust will keep the temp up which means the exhaust is less dense and flos better... what flows better thru a straw hot oil or cold oil backpressure is a missunderstood read the exhaust post
hey thats a 20 minute phone call "if i have seen farther it is by standing on the shoulders of giants" derek: do you know that non dairy cream is flamable Jennie: ...derek..what did you do
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Joined: Dec 2002
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Member 2000 Toyota Celica
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Member
2000 Toyota Celica
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I cannot add any more to this, well said before. Just here is the sound of my R2D2 Video [ c2design.hu]
Last edited by c2gas; Mar 23, 2005 3:10pm.
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05 WRB 2005 Subaru WRX STi
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05 WRB
2005 Subaru WRX STi
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Posts: 10,110 |
it is sort of like a wastegate... it lets off excess exhaust... that's what the 'pshhhhhhhhhhhhhh' is, lol. in n/a cars... you want back pressure... in turbo you want NO backpressure... that's why you get a 3'' exhaust. and the BOV lets off more excess exhaust eek not the backpressure demon again only reason you can't do a 3 inch exhaust on are na 4cyls is because of heat the air in the exhaust will get too cold cold ai is denser there for flos slower a 2.25/2.5 exhaust will keep the temp up which means the exhaust is less dense and flos better... what flows better thru a straw hot oil or cold oil backpressure is a missunderstood read the exhaust post to add to that, even when you have a 3" exhaust with no cats on a turbo car, you will experience boost creep.
SUBARU TECNICA INTERNATIONAL
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Posts: 10,110
05 WRB 2005 Subaru WRX STi
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05 WRB
2005 Subaru WRX STi
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and a BOV releases the pressure inside and is usually recycled usually, 100% atmospheric BOV's will cause you too lose boost = loss of power depending on the setup
SUBARU TECNICA INTERNATIONAL
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seabass 2000 Toyota Celica GTS
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seabass
2000 Toyota Celica GTS
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and a BOV releases the pressure inside and is usually recycled usually, 100% atmospheric BOV's will cause you too lose boost = loss of power depending on the setup and will run rich when the bov goes (instead of the air the maf reads gonig in to the engine half of it goes out the bov)
hey thats a 20 minute phone call "if i have seen farther it is by standing on the shoulders of giants" derek: do you know that non dairy cream is flamable Jennie: ...derek..what did you do
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Member 1993 Toyota Celica Alltrac
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1993 Toyota Celica Alltrac
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and will run rich when the bov goes (instead of the air the maf reads gonig in to the engine half of it goes out the bov) That's why AFM/MAF suck. It's much better to change to speed density system. to add to that, even when you have a 3" exhaust with no cats on a turbo car, you will experience boost creep. Only true with some turbos with internal wastegate setup. No problem with the external wastgate setup.
93 ST185, 91 ST185 (sold), 99 Solara SEV6 Boston
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Member 1992 Acura Integra GSR
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Member
1992 Acura Integra GSR
Joined: Oct 2004
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lol my friend had MAD boost creep on his DSM. Good thing he had a gauge or he would not have realized he was running 28psi on all stock stuff
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Posts: 10,110
05 WRB 2005 Subaru WRX STi
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05 WRB
2005 Subaru WRX STi
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Posts: 10,110 |
and will run rich when the bov goes (instead of the air the maf reads gonig in to the engine half of it goes out the bov) That's why AFM/MAF suck. It's much better to change to speed density system. to add to that, even when you have a 3" exhaust with no cats on a turbo car, you will experience boost creep. Only true with some turbos with internal wastegate setup. No problem with the external wastgate setup. exactly, in which you would want to port the wastegate on the internal setup but that does not always fix the problem.
SUBARU TECNICA INTERNATIONAL
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Thank you.: me, myself, and I...! Random: a bowl of rice, fried chicken, and a glass of water!
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