Wastegate vacuum source.. questions/theory
11-05-2004, 06:55 AM
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Wastegate vacuum source.. questions/theory
hey guys.. I know this subject has been covered very thoroughly, but no definite answer has ever been given. The topic is which vacuum source should I use for my wastegate?
There are two posibilities. One is the turbo or pre-intercooler charge pipe source. The other is an intake manifold source.
Turbo and pre-fmic source:
Pros: Helps a bit against compressor surge (as described in a pretty recent thread, so I wont go into detail. Here's the link : https://honda-tech.com/zerothread?id=975126 . It's about 2/3 of the way down.).
Cons: Engine will see max boost levels dependant on environmental temperatures. Since this source comes before the fmic, on cold days boost seen by the engine will be higher and on hot days, it will be lower. Very bad if you have a finely tuned car...
IM source:
Pros: Max boost level will be steady regardless of environmental temperature
Cons: Can cause slight compressor surge for slight second (yet again described in the very recent post).
So my question is.. what about tapping a nipple that come on the charge pipe AFTER the fmic, but before the TB? This *should* see the benefits of both worlds... please school me if I am wrong and/or missing something.. I also apologize if this has already been covered..
Also, does anyone know anything about spool up rates and boost creep depending on different wastegate vacuum source?
thanks guys
There are two posibilities. One is the turbo or pre-intercooler charge pipe source. The other is an intake manifold source.
Turbo and pre-fmic source:
Pros: Helps a bit against compressor surge (as described in a pretty recent thread, so I wont go into detail. Here's the link : https://honda-tech.com/zerothread?id=975126 . It's about 2/3 of the way down.).
Cons: Engine will see max boost levels dependant on environmental temperatures. Since this source comes before the fmic, on cold days boost seen by the engine will be higher and on hot days, it will be lower. Very bad if you have a finely tuned car...
IM source:
Pros: Max boost level will be steady regardless of environmental temperature
Cons: Can cause slight compressor surge for slight second (yet again described in the very recent post).
So my question is.. what about tapping a nipple that come on the charge pipe AFTER the fmic, but before the TB? This *should* see the benefits of both worlds... please school me if I am wrong and/or missing something.. I also apologize if this has already been covered..
Also, does anyone know anything about spool up rates and boost creep depending on different wastegate vacuum source?
thanks guys
11-06-2004, 10:39 PM
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Re: Wastegate vacuum source.. questions/theory (DOHCtah)
<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by DOHCtah »</TD></TR><TR><TD CLASS="quote">Also, does anyone know anything about spool up rates and boost creep depending on different wastegate vacuum source?
thanks guys</TD></TR></TABLE>
Id like to know this also, bump
thanks guys</TD></TR></TABLE>
Id like to know this also, bump
11-07-2004, 02:52 AM
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go at the manifold. I like to know exactly what's going into my engine. I read a few posts where people said that the difference between a boost gauged tapped at the turbo housing and one tapped at the manifold can be as much as 3psi difference. For a car only set to run 8 psi that's a HUGE difference.
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