Installed a Apexi BOV and it works good....
08-01-2002, 12:19 PM
#1
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Installed a Apexi BOV and it works good....
So i desided to bolt up a Apexi twin chamber blow off valve to my 951.The reason i bought a Apexi is because i got a good deal from the distributor here in Montreal. I used one with a 93-95 rx-7 adapter and it worked great. I know blow off to the atmosphere and it works great. No dropping idle, no smoke betwen shift,no running rich.
It Blow off real fast,much faster then my wastegate for example. When i shift i first hear my BOV,then al most a the end of the BOV discharge my stock atmospheric wastegate opens.
I will be posting pics and audio ove my TEMPORARY setup(untill i find better tubing to make it perfect). Here's a pic of the valve it self
It Blow off real fast,much faster then my wastegate for example. When i shift i first hear my BOV,then al most a the end of the BOV discharge my stock atmospheric wastegate opens.
I will be posting pics and audio ove my TEMPORARY setup(untill i find better tubing to make it perfect). Here's a pic of the valve it self
08-01-2002, 07:17 PM
#5
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[quote] I thought venting to the atmosphere was not possible on our cars? <hr></blockquote>
From what i know, when venting to atmosphere you great a rich condition because you just vented a calculated amount of air,and then you end up with too much full for the amount of air left.
But i have been running it for 1 day and it works good, i am not puffing or running extra rich.
I will take notes of my a/f ratio guage on my way home from work to see if it really see a difference on the guage. But up to know i did not notice my guages indicating richer when im venting.
[quote] Does venting to the atmosphere cause any running problems ? <hr></blockquote>
Well beside's runing rich when venting, i don't think there's other side efects.
Here is some info i found on the web about BOV to help clear up why upgrading BOV/or DV with a high performance.(it a bit long sorry)
• Most turbo cars have some form of factory blow off valve (sometimes referred to as bypass or anti-surge valves), most of which dump the excess turbo pressure back into the inlet to reduce or eliminate the associated noise. It is common for factory valves to open at very slight vacuum signals, meaning that whenever your manifold pressure is not experiencing boost, the valve is wide open and is recirculating a significant amount of air from the turbo's outlet to it's inlet. This means that for about 95% of the time that you are driving your car, the turbo is trying to generate boost but can't until the valve shuts. In this condition you might as well take the turbo off the car!
If a slight throttle increase is made (say to maintain speed on a freeway up a small rise) and the manifold pressure makes the transition from vacuum to boost, the valve closes. So the rather significant amount of air that has been pumped around in circles by the turbo is now pressurized and directed at the engine. The end result is an annoying surge that makes freeway speeds difficult to maintain.
A high performance blow off valve uses the correct spring pressure to keep the valve closed until it is needed, so that the turbo's energy is not going to waste at light throttle applications. End result? You now use less throttle to drive the car around for the 95% of the time that is not spent on boost, meaning better fuel economy.
• A factory blow off valve is only designed to cope with factory levels of power, and tests performed on a variety of them show that they leak significantly at boost pressures as low as 3psi! Why waste that boost? It is also important to realize that a small boost increase of 2-3psi will quite dramatically increase the speed of the turbo and the airflow passing through it, and it is almost certain that a factory valve will not be able to vent the required volume quickly enough to prevent damage to the turbo.
• If you want people to know that you are driving a turbocharged car, you need the WHOOOSH noise between gear changes!
From what i know, when venting to atmosphere you great a rich condition because you just vented a calculated amount of air,and then you end up with too much full for the amount of air left.
But i have been running it for 1 day and it works good, i am not puffing or running extra rich.
I will take notes of my a/f ratio guage on my way home from work to see if it really see a difference on the guage. But up to know i did not notice my guages indicating richer when im venting.
[quote] Does venting to the atmosphere cause any running problems ? <hr></blockquote>
Well beside's runing rich when venting, i don't think there's other side efects.
Here is some info i found on the web about BOV to help clear up why upgrading BOV/or DV with a high performance.(it a bit long sorry)
• Most turbo cars have some form of factory blow off valve (sometimes referred to as bypass or anti-surge valves), most of which dump the excess turbo pressure back into the inlet to reduce or eliminate the associated noise. It is common for factory valves to open at very slight vacuum signals, meaning that whenever your manifold pressure is not experiencing boost, the valve is wide open and is recirculating a significant amount of air from the turbo's outlet to it's inlet. This means that for about 95% of the time that you are driving your car, the turbo is trying to generate boost but can't until the valve shuts. In this condition you might as well take the turbo off the car!
If a slight throttle increase is made (say to maintain speed on a freeway up a small rise) and the manifold pressure makes the transition from vacuum to boost, the valve closes. So the rather significant amount of air that has been pumped around in circles by the turbo is now pressurized and directed at the engine. The end result is an annoying surge that makes freeway speeds difficult to maintain.
A high performance blow off valve uses the correct spring pressure to keep the valve closed until it is needed, so that the turbo's energy is not going to waste at light throttle applications. End result? You now use less throttle to drive the car around for the 95% of the time that is not spent on boost, meaning better fuel economy.
• A factory blow off valve is only designed to cope with factory levels of power, and tests performed on a variety of them show that they leak significantly at boost pressures as low as 3psi! Why waste that boost? It is also important to realize that a small boost increase of 2-3psi will quite dramatically increase the speed of the turbo and the airflow passing through it, and it is almost certain that a factory valve will not be able to vent the required volume quickly enough to prevent damage to the turbo.
• If you want people to know that you are driving a turbocharged car, you need the WHOOOSH noise between gear changes!
08-01-2002, 08:32 PM
#6
Racer
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ricers vent to the atmosphere to make noise; any system that cares about performance will use a closed loop BOV in order to recirculate the air through the turbo and slow the despool between shifts; the wastegate is what should slow the turbo because it's
A) before the turbo and thus will slow what is driving the turbo instead of keeping the turbo spinning and pushing useless air
B) it's faster then a BOV because it's again "upstream" in the system; id est before the turbo
C) the wastegate is computer controled and can be actuated acording to what the computer wants the car to do; a BOV is just a dumb valve that opens when pressure builds
let ricers rent the fast and the furious and use open loop BOV's in order to be loud; They can tell me what my tail lights looks like when i hit second. <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
A) before the turbo and thus will slow what is driving the turbo instead of keeping the turbo spinning and pushing useless air
B) it's faster then a BOV because it's again "upstream" in the system; id est before the turbo
C) the wastegate is computer controled and can be actuated acording to what the computer wants the car to do; a BOV is just a dumb valve that opens when pressure builds
let ricers rent the fast and the furious and use open loop BOV's in order to be loud; They can tell me what my tail lights looks like when i hit second. <img src="graemlins/burnout.gif" border="0" alt="[burnout]" />
08-01-2002, 10:47 PM
#7
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[quote] it's faster then a BOV because it's again "upstream" in the system; id est before the turbo <hr></blockquote>
Not true, i'm running an atmospheric wastegate and i can perfectly hear it when it open, and the wastegate opens way after the BOV.
My BOV also stay open alot longer than my wastegate because it need to remove all excess pressure witch the turbo keep spinning even after the wastegate has vented some pressure.
A wastegate is to controle boost, A BOV is to vent unused pressure in the intake track when you close the throtle.
I know venting to the atmosphere is not the best way to blow off for performance,but the stock setup IMO is not the best ither.
The stock valve needs a stronger spring to hold up to vacum.
I got this BOV because i wanted to try something new and im happy with the result considering what i paid for it.If i get bored of it i'll sell it.
And i can see why you think atmospheric BOV are only for ricer. But IMO having a turbo car and not hearing the Blow off is a bit boring.
I love the sound of a spooling turbo,the groull of a wastegate and the pressure relif of a BOV,and if those sound could only be heard in the car, i would be in paradise. But since it's comming from the engine bay then everybody must hear it too.
If liking the sound of a turbo car is RICE then i guess you can call me a RICER <img src="graemlins/crying.gif" border="0" alt="[crying]" /> <img src="graemlins/crying.gif" border="0" alt="[crying]" />
Not true, i'm running an atmospheric wastegate and i can perfectly hear it when it open, and the wastegate opens way after the BOV.
My BOV also stay open alot longer than my wastegate because it need to remove all excess pressure witch the turbo keep spinning even after the wastegate has vented some pressure.
A wastegate is to controle boost, A BOV is to vent unused pressure in the intake track when you close the throtle.
I know venting to the atmosphere is not the best way to blow off for performance,but the stock setup IMO is not the best ither.
The stock valve needs a stronger spring to hold up to vacum.
I got this BOV because i wanted to try something new and im happy with the result considering what i paid for it.If i get bored of it i'll sell it.
And i can see why you think atmospheric BOV are only for ricer. But IMO having a turbo car and not hearing the Blow off is a bit boring.
I love the sound of a spooling turbo,the groull of a wastegate and the pressure relif of a BOV,and if those sound could only be heard in the car, i would be in paradise. But since it's comming from the engine bay then everybody must hear it too.
If liking the sound of a turbo car is RICE then i guess you can call me a RICER <img src="graemlins/crying.gif" border="0" alt="[crying]" /> <img src="graemlins/crying.gif" border="0" alt="[crying]" />
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08-01-2002, 11:24 PM
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It's purely preference. Closed loop is fine and stealthy but atmosphereic venting is fine too, as long as you're set up to do that. Just because Edman likes his whoosh doesn't mean he's a ricer. I have seen kits that place a speaker under the hood and FAKE that noise on N.A. cars.. THAT's rice!
If venting to atmosphere hurt performance, then why do you hear the sharp whoosh during WRC?
If venting to atmosphere hurt performance, then why do you hear the sharp whoosh during WRC?
08-02-2002, 11:37 AM
#10
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So if I wanted to vent to the atmosphere could I simply block the inlet on the intercooler pipe being fed from the dump valve and leave the dump valve to vent to the air??? <img src="confused.gif" border="0">
08-02-2002, 12:15 PM
#11
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[quote] So if I wanted to vent to the atmosphere could I simply block the inlet on the intercooler pipe being fed from the dump valve and leave the dump valve to vent to the air??? <hr></blockquote>
First you need to upgrade you BOV, the stock one CANNOT be used to vent to the atmosphere.
To vent to atmosphere you must conect your BOV to the intake tube just before the throttle body. And plug up the hold in the intake boot next to the coolant over flow tank.
Just like this guys.
I will post pics of my setup soon.
First you need to upgrade you BOV, the stock one CANNOT be used to vent to the atmosphere.
To vent to atmosphere you must conect your BOV to the intake tube just before the throttle body. And plug up the hold in the intake boot next to the coolant over flow tank.
Just like this guys.
I will post pics of my setup soon.
08-02-2002, 02:41 PM
#12
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[quote] First you need to upgrade you BOV, the stock one CANNOT be used to vent to the atmosphere. <hr></blockquote>
Well, that's not really the case. The stock compressor bypass valve isn't really any different in function than any of the aftermarket valves, it's just not as durable. I've been venting to the atmosphere with the stock valve ever since my SDS install in February. It works just fine and sounds kickass too!
Well, that's not really the case. The stock compressor bypass valve isn't really any different in function than any of the aftermarket valves, it's just not as durable. I've been venting to the atmosphere with the stock valve ever since my SDS install in February. It works just fine and sounds kickass too!
08-02-2002, 03:37 PM
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[quote] Well, that's not really the case. The stock compressor bypass valve isn't really any different in function than any of the aftermarket valves, it's just not as durable. <hr></blockquote>
Really,is yours modified or anything because my valve did not leak under boost but when i tried to run my stock valve to atmosphere the car could'nt hold idle because it would take in air on vacum.The only time i could get the car to hold an idle was when i disconected the top vacum hose,but then it did not vent. Does this mean my stock valve was busted??? but i think its a 993 valve too...
Really,is yours modified or anything because my valve did not leak under boost but when i tried to run my stock valve to atmosphere the car could'nt hold idle because it would take in air on vacum.The only time i could get the car to hold an idle was when i disconected the top vacum hose,but then it did not vent. Does this mean my stock valve was busted??? but i think its a 993 valve too...
08-02-2002, 07:49 PM
#15
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Since Russ is running the SDS it dosen't matter if his is open during idle because it is unmetered air for him. If you are still useing a AFM or MAF then it will give you a problem.