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

[Mihnea Cotet]

Ned, what about the small #6 K26 hot side (50mm exducer bore) used on oil 
cooled K26s???? MTM do such a turbo with a water cooled bearing housing, 
small turbine wheel and hot side housing, bolted on a 7200 cold side, and I 
happen to have one here on the bench...

Mihnea

At 10:11 23/12/2003 -0800, Ned Ritchie wrote:
>A few of you already know from that for a sacrifice of about 10 hp at
>the top I've used a custom turbo from the folks at 3K that will give RS2
>power lower in the rpm range like 2400 rpm
>For the purpose of comparison here are the specs.  All are RS2
>compressors with the 10 mm shaft.  The differences are only in the
>turbine section.
>
>K24  2672 GGC  6.13 -- Stock sized S4/S6 turbine
>K24  2672 GGC  6.11 -- Custom size between stock and RS2
>K24  2672 GGC  6.12 -- RS2 sized turbine
>
>(Yes, I know the numbers appear wrong for the turbine sizes, but that is
>how 3K does it)
>
>On a twisty track or in and around town you can't beat the 6.11 turbine
>
>Ned
>
>-----Original Message-----
>From: s-car-list-bounces at audifans.com
>[mailto:s-car-list-bounces at audifans.com] On Behalf Of QSHIPQ at aol.com
>Sent: Tuesday, December 23, 2003 5:36 AM
>To: mik at info.fundp.ac.be; gary.m.lewis2 at boeing.com;
>s-car-list at audifans.com
>Subject: Re: [s-cars] Bypass Valves and Pressure Losses (Uh, Pizzo??)
>
>I agree Minhea.  Look guys, if you are looking for 26psi on the I5, the
>RS2
>will hit it.  If you are looking for Flow at 26psi for xxxhp, the RS2
>(modified
>cold side) can hit it (I say up to about 480 or so - Minhea?).  If you
>are
>looking for 26psi at low RPM's on a 2.3L motor, I can't think of a
>better turbo
>for the task (well I can think of one, but Herr Meyer gets a lot of
>money for
>it).  If you take a big turbine and try to get it to do big things with
>a
>small motor, you will hit the surge line very quickly.  Surge sucks.
>
>Someone really (hey let's get Mikey) should put a couple of these
>mongosized
>turbo hybrids on a turbo dyno.  Chassis dynos only give part of the
>story, as
>several here are finding out.  I'm intrigued by solving turbo problems
>with
>bypass valves.  In fact Gary, using this logic, you are actually going
>to
>'increase' pressure losses to get 26psi at 3k.  Part throttle may just
>require
>bleeding of boost as several here will find out.  Especially at
>altitude, these
>problems are going to get worse, cuz the turbo is spinning faster to
>attain the
>same pressure ratio, which means a bigger problem at part throttle.
>
>IMO, you are going to see dual sequential turbos (already here) and
>modified
>scroll design (already here) as alternatives to one monster turbo trying
>to be
>both a lamb and a lion.
>
>My .02 arbitraged thru the peso
>
>Scott Justusson
>QSHIPQ Performance Tuning
>
>
>
>
>
>In a message dated 12/22/2003 1:52:22 PM Central Standard Time,
>mik at info.fundp.ac.be writes:
>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
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