[s-cars] Bypass Valves and Pressure Losses (Uh, Pizzo??)

[Lewis, Gary M]

Hi Hap,
 
I oriented it from the bottom (pressure side), as the instructions indicated, with 6 shims, as Pizzo indicated.  It works far better than the old 710N unit from a pressure loss standpoint (I gained 200 rpm in 4th gear).  My current automotive goal in life is to reduce pressure losses in hope of getting 26 psi at 3,000 rpm.  I'm making progress.
 
I think the idea you postulate is really a neat one.  It should provide far better response than a shimmed-to-the-max BPV.  Uses vaccuum primarily, not pressure and vaccum to open the valve.  I will try it.
 
Sorry I took so long to answer, but I needed to think about this for a few days.
 
That Trevor is something else, ain't he?  The more I talk to him (virtually of course), the more I want to drive his car.  No to mention your of course...
 
Thanks Again,
Gary Lewis 

1995.5 S6 Avant, Green/Ecru, RS2 MAF, RS2 Exhaust Manifold, RS2 Injectors, Custom Turbo (K26 Turbine, Factory K26 Cold side (Audi Works '999' P/N) with 50mm intake and custom Innovative Turbo compressor wheel), TurboXS Type 25 Bypass Valve, Bilsteins, Eibachs, Big Reds, Spec II Clutch.

	-----Original Message-----
	From: CaptMagu at aol.com [mailto:CaptMagu at aol.com] 
	Sent: Thursday, December 18, 2003 1:23 PM
	To: Lewis, Gary M; s-car-list at audifans.com
	Subject: Re: [s-cars] Bypass Valves and Pressure Losses (Uh, Pizzo??)
	
	
	Gary
	
	I have the H34 TurboXS right now. Do you have it plumbed from the side? In other words is the pressure feed from the turbo plumbed into the side of the piston. If not you'll want to reorient it this way and then you won't need any washers. In fact I went to a softer/shorter spring. I had shimmed my old H34 like crazy, well beyond the provided washers and was still having a problem getting it to hold boost. I talked directly to the TurboXS folks a while back when there was a thread running on mounting BPVs backwards. They admitted that for high hp applications that this was the way to go and sent me a brand new H34 configured for a hard mount at the side. Tha's what I have now but even with the softer/shorter spring I'm still getting that boost surge at throttle lift from boosted runs. It was Trevor Frank's idea to try a softer spring and it has greatly improved the problem but has not totally fixed it. My next try is a beefier diaphram unit. The stock Mitsu EVO BPV couldn't hold my turbo's force.
	
	Hap, boostin and surgin in Everboost, Maguire