BOV vacum location???
#1
Captain Obvious
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BOV vacum location???
I'm looking to locate a vacum line for the BOV on my '85 928. I need a location past the throttle plate. The BOV needs a vacum line that is different when the throttle is closed. They operates on the principle of difference in pressure. All the ones I found under the hood so far are under constant vacum. This keeps the BOV open all the time.
#4
Captain Obvious
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Tom,
Thanks for the info. Sent you a PM regarding the FMU.
Curtis,
I think the brake booster line is under constant vacum, regardless of the throttle plate position. Or am I mistaken?
Thanks for the info. Sent you a PM regarding the FMU.
Curtis,
I think the brake booster line is under constant vacum, regardless of the throttle plate position. Or am I mistaken?
#5
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Typically the brake booster is straight off the intake manifold. On the '86.5 it's off the left intake plenum.
The feed to the "spider" is "port timed" and is found on the throttle body.
The feed to the "spider" is "port timed" and is found on the throttle body.
#7
Captain Obvious
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Ok, let me get this straight. Since I’ve never used a BOV in any of my previous SC applications its operation is not completely clear to me. I thought it was but it’s apparent that what I think I know is not accurate.
A BOV will vent during idle and off boost, right? It will also close as soon as vacuum reaches 0 and goes into boost, right? Is it necessary to run the vacuum line for the BOV past the throttle plate?
As for the BOV location, it's located at the middle of the radiator so eithe side of the TB will do. The easier to get to the better it will be for me.
A BOV will vent during idle and off boost, right? It will also close as soon as vacuum reaches 0 and goes into boost, right? Is it necessary to run the vacuum line for the BOV past the throttle plate?
As for the BOV location, it's located at the middle of the radiator so eithe side of the TB will do. The easier to get to the better it will be for me.
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BOV is for venting excess pressure. If you have the throttle wide open then close it the turbo/sc is trying to cram air into an engine that doesn't want it. The BOV, prevents over boost. That's why you here the pop and squeel when boosted cars shift. The revs drop, more air is provided than needed, pressure goes up, excess air is 'blown off'.
I guess you could also use it to get boost earlier without over boosting at higher revs with an SC. That's one of the purposes of a wastegate on a turbo.
Edited to add: I would think you'd want your vacuum/pressure line to be on the intake side of the throttle, not the engine side. If it was on the engine side, that line could have vacuum while the other side is still building (too much) pressure.
I guess you could also use it to get boost earlier without over boosting at higher revs with an SC. That's one of the purposes of a wastegate on a turbo.
Edited to add: I would think you'd want your vacuum/pressure line to be on the intake side of the throttle, not the engine side. If it was on the engine side, that line could have vacuum while the other side is still building (too much) pressure.
#11
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AAhhhm never mind, I asked before i read the whole page Curtis has. At the bottom, explains the operation of a BOV (factory and aftermarket). For now I'm using a '93 ZX300TT BOV and it operates different than the aftermarket type. I will "T" into the fuel pressure regulator as a sorce.
Thanks for all the help!
Thanks for all the help!