Missing Boost

Baer383 · 08-09-2013, 10:30 AM

Quote:

Originally Posted by pokeyl

New one is onthe way. The fix for now was Ace hadware springs. After the new spring install the valve is half-way open at idle. Under full boost it sould be full open from the SC pressure and the high vaccuum. At cruse it should be full closed. It should closer sooner as it is only part open at 15-18 inches of vaccuum. The old valve has never held up to full 1.5 SC boost. It will be fun to see if my new setup can handle 10PSI.

It should be open at idle,closed when you floor it and it will flutter under part throttle cruise.

pokeyl · 08-09-2013, 12:53 PM

It is open 1/2 at idel with 17 inchs of vaccuum. When I tested it with my vaccuum pump it was bypassing so much I could not generate enough suction to pull it open using my standard brake vaccuum bleeder hand pump. New one is on the way, tomorrow??? maybe today???

Sh0velMan · 08-09-2013, 01:08 PM

Quote:

Originally Posted by Baer383

It should be open at idle,closed when you floor it and it will flutter under part throttle cruise.

Hmm. My understanding of such things from my experience with my various F.I. cars, is that the BOV should be closed at all times, except when there is a pressure differential between the intake manifold and cold pipe, meaning the TB is closed but there's still boost in the cold pipe(s).

If it were open at idle, and you ran an un-recirculated BOV, you'd be sucking unfiltered and unmetered atmospheric air at idle...

I could be completely wrong though. Wouldn't be the first or last time.

luigi90210 · 08-09-2013, 02:38 PM

Quote:

Originally Posted by Sh0velMan

Hmm. My understanding of such things from my experience with my various F.I. cars, is that the BOV should be closed at all times, except when there is a pressure differential between the intake manifold and cold pipe, meaning the TB is closed but there's still boost in the cold pipe(s).

If it were open at idle, and you ran an un-recirculated BOV, you'd be sucking unfiltered and unmetered atmospheric air at idle...

I could be completely wrong though. Wouldn't be the first or last time.

i have always been told this as well, with a BOV you want to keep it closed until you let off the throttle which would release all the pressurised air and prevent compressor surge

with a BPV you can have slightly open at idle or completely closed because you are recirculating after the MAF so either way, you are taking in the same amount of air since its been accounted for via MAF

also there is no such thing as a recirculated blow off valve since a blow off valve, blows off the pressurised air into the atmosphere while a bypass valve, allows the compressed air to bypass the turbo/supercharger and is recirculated in the system, since internally they are the same, the set up ultimately determines what the valve will function as(IE remove the recirc hose from the BPV and you now have a BOV and vise versa)

if im wrong about anything though, anyone please feel free to correct me but afiak bov and bpv are the same internally, just depends on how it is set up

pokeyl · 08-09-2013, 04:04 PM

[

pokeyl · 08-09-2013, 01:12 PM

Quote:

Originally Posted by Baer383

It should be open at idle,closed when you floor it and it will flutter under part throttle cruise.

Mine sounds like a sewing machine at part cruse.

08-09-2013, 12:53 PM	#2 (permalink)
pokeyl Track Member Join Date: Nov 2010 Location: DFS Posts: 901 Drives: ??? Rep Power: 55	It is open 1/2 at idel with 17 inchs of vaccuum. When I tested it with my vaccuum pump it was bypassing so much I could not generate enough suction to pull it open using my standard brake vaccuum bleeder hand pump. New one is on the way, tomorrow??? maybe today??? __________________ It's not my fault I'm old, I was born a very long time ago! Last edited by pokeyl; 08-09-2013 at 01:11 PM.

08-09-2013, 04:04 PM	#5 (permalink)
pokeyl Track Member Join Date: Nov 2010 Location: DFS Posts: 901 Drives: ??? Rep Power: 55	[ __________________ It's not my fault I'm old, I was born a very long time ago! Last edited by pokeyl; 08-09-2013 at 04:10 PM.

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