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

[Mihnea Cotet]

Gary,


If you had had a real RS2 turbo (I know the turbo itself is way too 
expensive, I know!), you could have gotten 26 psi at 2.6k in 4th gear while 
accelerating WOT from 2k RPM.

Just my 0.02 Euros worth of 20vt engines tuning,

Mihnea

At 11:43 22/12/2003 -0800, Lewis, Gary M wrote:
>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
>
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