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

[Lewis, Gary M]

Agreed Mihnea.

The REAL RS2 turbo is limited by the turbine side wheel being the smallest of the K26 line.  I don't have that limitation, and I also have a much larger compressor wheel and housing.  I have a 600RPM penalty vs. the Rs2, but I also have the rpm range above 3,200 in performance.  I understood the trade-off vs. a $1,000 premium for the RS2, and I took the custom K26.  I have no regrets.

My suggestion?  If someone is into high-performance at low rpm, go with the RS2.  If you want all out performance above 3,000 rpm, check out some of the other turbo's available (Custom K26's/K27's or Garretts').

I have all the parts to build a psuedo RS2 comp, but I don't think I'm going to.  I'm having too much fun with the turbo I have.

Thanks,

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: Mihnea Cotet [mailto:mik at info.fundp.ac.be] 
> Sent: Monday, December 22, 2003 12:51 PM
> To: Lewis, Gary M; s-car-list at audifans.com
> Subject: RE: [s-cars] Bypass Valves and Pressure Losses (Uh, Pizzo??)
> 
> 
> 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
> >
> >_______________________________________________
> >S-CAR-List mailing list
> >S-CAR-List at audifans.com 
> >http://www.audifans.com/mailman/listinfo/s-car-list
> 
>