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Discussion Starter · #1 ·
I know it sounds like a stupid question, but is there anywhere in the intake path that's below atmospheric pressure during full boost operation - e.g. at the s/c or turbo compressor intake? I think I'd need a couple of psi below at least.

Cheers.
 

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? I would assume their would be a huge suction goin on in the intake once the turbo starts spooling.. think about it.. the turbos pretty much sucking the air in, and a sucktion would have much less atmospheric pressure than the piping past the turbo which is being compressed..
 

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the only part of the system that wouldnt be under any pressure is the intake for the turbo. but there wouldnt be any vacume pressure, just outside pressure
 

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Discussion Starter · #4 ·
Smaay said:
the only part of the system that wouldnt be under any pressure is the intake for the turbo. but there wouldnt be any vacume pressure, just outside pressure
Hmm, that's what I was worried about - I suppose if the intake to the turbo is made from decent diameter tube, there won't be much of a pressure drop below atmospheric even with 100's of cfm of air flying by.

Do you think a PCV-valve is a good enough valve to use to make a vacuum reservoir?
 

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Gravel said:
Do you think a PCV-valve is a good enough valve to use to make a vacuum reservoir?
The one for the brake booster is designed to hold vacuum. It might be a better candidate.
dB
 

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deltaB said:
Gravel said:
Do you think a PCV-valve is a good enough valve to use to make a vacuum reservoir?
The one for the brake booster is designed to hold vacuum. It might be a better candidate.
dB
Yup yup - thats the route I would go.

What are you running off vacuum under boost?
 

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Discussion Starter · #7 ·
Boosted2.0 said:
Yup yup - thats the route I would go.

What are you running off vacuum under boost?
I don't think I'd want to risk losing my brake-assist after a shed load of boosting ;)

I might add another one though, but I'm also considering using a venturi pump on the intake or a cruise-control pump if I can find one second-hand.

I just need enough vacuum to operate a valve but I need to have an endless supply of vacuum - hmm, sounding more and more like a pump to me.
 

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Any area after the TB is under ported vacuum, any area outside (intake) is atmospheric, 14.7psi.
 

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If you're worried about brakes you'll have brake assist the moment you lift off the throttle.

Otherwise, there are some simple vacuum reservoirs designed for the V8 guys and diesels as well as electric pumps as somebody else mentioned.
 

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monkeywrench said:
If you're worried about brakes you'll have brake assist the moment you lift off the throttle.

Otherwise, there are some simple vacuum reservoirs designed for the V8 guys and diesels as well as electric pumps as somebody else mentioned.
I was under the impression he was making a vacuum reservoir. I remember the #10 coffee cans under the hoods of mid-70s fords. I was suggesting to use the same type check valve as the one for the brake booster, not tap into the booster itself.
dB
 
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