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wastegate vacuum source question

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Old 08-09-05, 09:45 PM
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wastegate vacuum source question

hi, im almost done with my gt35r single install and i need a pressure source before the throttle plates according to the diagram below for the boostcontroller. Where can i buy a vacuum nipple that i can get welded onto the intercooler piping right after the turbo?
thanks,
Craig

Old 08-10-05, 10:20 AM
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I send a UIM nipple source to the input of my MBC and the output to the bottom of my WG. It seemed to spool a little faster that way maybe because I didn't have a vent???
Old 08-10-05, 01:31 PM
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Ideal place is not on the UIM/ b/c the wg “could” see vacume in between shifts and over spool or some strange phenomenon like that.

Best spot is right on the compressor discharge tube, you probably have seen many people have a vac bung on the compressor housing
If you don’t feel up to drilling and taping the comp housing here is a great fix

http://www.atpturbo.com/Merchant2/me...egory_Code=BCS

It’s called the quick tap, goes right into the silicone connector, I use one with my profec b and couldn’t be happier
Old 08-10-05, 01:56 PM
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Almost forgot your not looking for a wg vacuum source, your looking for a Non-Vacuum Boost source:-)
Old 08-10-05, 04:59 PM
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Originally Posted by Bacon
Ideal place is not on the UIM/ b/c the wg “could” see vacume in between shifts and over spool or some strange phenomenon like that.
well, I guess I should have gone into my more detailed explaination of my boost control...I did put a solenoid inline with the output line on the BC. It keeps any signal away from the WG until ~10psi. I was trying to achieve faster spool with a MBC, did I? I don't know. But I do not have a vaccum source creating some strange phenomenon...that I have never heard of?!?

between shifts my WG shuts.
Old 08-10-05, 06:45 PM
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The “strange phenomenon” is having the Turbo still spooling in between shifts, now it definitely will help with lag in between shifts, but if your WG is closed during shifts, the turbo is still spooling, now when you go into the next gear lag is not as noticable but you take the chance of over boosting (depending on how much you Wg can flow.) Most of us single guys run larger WG that we would need by design just to be safe. But think of running 20+psi into a motor, the volumetric flow going through the turbo under boost is high, when your shifting the bov is letting the over flow off but in your case the turbo is still spooling. Although the volume of exhaust gas is lower the turbo is still spinning @ speed, and not only can out flow your BOV, but when you go into the next gear you could spike and POP. And it may not even be that your Wg cant flow, it could simply be the delay in the system between pressure, to valve switching, to Wg actuation

Not saying your setup doesn’t work great but they design, and recommend it with a non vac source for a reason.

Any of the Pros in here want to shed some light on this situation? Im far from a pro, and its been a while since I’ve read up on turbo system design.
Old 08-10-05, 10:50 PM
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back to my question. where can i buy a vacuum nippple that i can get welded into the intercooler piping right after the turbo, i dont wanna do that quicktap into the silicone coupler and i dont want to tap the compreser housing. can i just buy a 1/4" stainless steel tube and get that welded into the piping?
Old 08-10-05, 11:19 PM
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With my GT35R kit, my boost was smoother by moving my pressure source from the turbo outlet to the elbow before the throttle body.
Old 08-10-05, 11:26 PM
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just make it work. take a trip to home depot.. look for the racing department.
Old 08-12-05, 08:38 AM
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www.burnsstainless.com
Old 08-12-05, 09:45 AM
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Originally Posted by Bacon
The “strange phenomenon” is having the Turbo still spooling in between shifts, now it definitely will help with lag in between shifts, but if your WG is closed during shifts, the turbo is still spooling, now when you go into the next gear lag is not as noticable but you take the chance of over boosting (depending on how much you Wg can flow.) Most of us single guys run larger WG that we would need by design just to be safe. But think of running 20+psi into a motor, the volumetric flow going through the turbo under boost is high, when your shifting the bov is letting the over flow off but in your case the turbo is still spooling. Although the volume of exhaust gas is lower the turbo is still spinning @ speed, and not only can out flow your BOV, but when you go into the next gear you could spike and POP. And it may not even be that your Wg cant flow, it could simply be the delay in the system between pressure, to valve switching, to Wg actuation
I don't follow how my turbo can spike with no [reasonable] exhaust flow spinning the turbine, with my foot off the throttle??? The WG never sees vacuum with the solenoid in place...even when it did [see vac], I never had a spike. Maybe if I was running 4-7psi and my BOV and WG were undersized, but I'm running 17psi and the components are sized properly.

I would love to hear someone else's view on this strange phenomenon...I'm not trying to argue...just don't follow the logic.


even if the source was a +pressure only source, that pressure isn't enough to hold the WG open during shifts.
Old 08-12-05, 10:13 AM
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You are right,

I retract above statements, I was remembering problems some people I have know who had undersized components. I.e. small Wg. I re-read what I posted after I drank my coffee yesterday and was like “I’m a retart” Lol

It’s all relative to how you drive it and what works for you,
Realistically the way you have it set up is like having the sharp setting tuned up on the boost controller. If you vent it till you get the psi you want to you have a solenoid wired inline to keep it form seeing boost its all the same. Keep the gate shut until the last possible second.
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