Single Turbo RX-7's Questions about all aspects of single turbo setups.

Tell me about the POV :)

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Old 08-24-07, 12:00 AM
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Tell me about the POV :)

i was reading somewhere in a sticky that its recommended to use a POV in conjunction with a smaller wastegate to keep the turbo spooled up i guess? can someone explain to me how this works? its late and im having trouble seeing how this wont kill your turbo.
Old 08-24-07, 09:17 AM
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Have you even considered doing your own search on "POP OFF VALVE"?
Old 08-24-07, 09:27 AM
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Wastegates don't really have much to do with Spool. Spike definitely. POV is more a safety device, not a boost or spool controlling device.
Old 08-24-07, 09:31 AM
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a POV is a big hole in your Manifold with with a BOV that doesn't seal screwed/welded/attached to it. Your wastegate may be set for 15pounds and if you make 20psi ore something, the POV will pop open, dumping all your boost (even at full throttle), not blowing your engine.
Old 08-24-07, 09:41 AM
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Wastegates don't really have much to do with Spool. Spike definitely. POV is more a safety device, not a boost or spool controlling device.
Old 08-24-07, 11:08 AM
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Originally Posted by cewrx7r1
Have you even considered doing your own search on "POP OFF VALVE"?
Have you even considered being less lame??? i searched and read everything i could. you know im not asking HOW a pop off valve works, read it again. dont give me some stupid "youre a newb search" answer.

Originally Posted by Zero R
A POV(pop off valve) not to be mistaken with a BOV(blow off valve). This can help with response greatly. By running a smaller wastegate(or even no wastegate in some) and using a POV you can get better crisper response. One of the reasons is a wastegate opens slowly bleeding off exhaust. Diverting any exhaust energy will obviously slow down how quickly the turbine wheel reaches it's desired maximum. Combine this with a constant on/off of the throttle and the wastegate fluctuates creating a rotating assembly that is speeding up and slowing down. Smoothing out those fluctuations will smooth out your response and power delivery. The wastegate then kinda works as a reliever of backpressure before the turbine, which in turn helps with reversion. This is nothing new. There are a lot of teams/builders out there doing this, and it was done back in F1's turbo days as well.

no one read what i asked i guess. im asking how this doesnt hurt your turbo.
Old 08-24-07, 06:29 PM
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Originally Posted by imloggedin
Have you even considered being less lame??? i searched and read everything i could. you know im not asking HOW a pop off valve works, read it again. dont give me some stupid "youre a newb search" answer.
no one read what i asked i guess. im asking how this doesnt hurt your turbo.
DOH!!!!
Old 08-25-07, 06:12 AM
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i fail to see where he says it wont "hurt the turbo" the way i read it, he states that it will aid in spool by essentially creating boost creap w/ smaller wastegate using more exhaust energy instead of bypassing it. BUT you NEED the POV to bleed the extra pressure off, so your not constantly increasing boost. ie: your are limited to said pressure 10,15,20.
in no way was it said it will not put extra stress on the turbo. anytime you spool a turbo you are stressing it and with this set up you are stressing it all the time since you will usually have at least a small amount of boost.
that is the way i read the post from zero r but i did not read the whole conversation either
this is my understanding of what you posted if anyone else has another idea please feel free to share
later
z
Old 08-25-07, 06:16 AM
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i would also recommend the book MAXIMUM BOOST by Corkey Bell it is not really current with modern day turbos but the theories in it ar eessentially the same, we just have more technology than when that book came out late 80's if my memory serves me
later
z
Old 08-25-07, 08:20 AM
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PM aspec, he has posted before about using this for boost control on a LARGE single turbo.
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