[Diy_efi] Compressor "surge ring"

Grant Beaty gbeaty at ufl.edu
Fri Jan 31 16:06:35 GMT 2003


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"...It is also possible for the surge to occur in the diffuser of the
compressor housing due to the dynamics of the system. In this case what =
is
called a ported shroud compressor housing is used. You might have seen =
these
on really big turbos. A ported shroud looks like a really big inlet bib =
with
the inducer bore of the housing inside it. Looking closer, you can see =
an
annular groove around the inducer of the compressor in the housing. What
this does is allow air to recirculate around the compressor wheel at =
higher
boost pressures, "fooling" the compressor into thinking it is actually
flowing more and helping prevent surge. This also costs you some peak
efficiency but preventing surge is much more important. Ported should
housings are useful in preventing surge at higher pressure ratios."

I'm wondering if anyone has experiences with the real-world gains (or =
losses) of one of these housings.

Thanks,
Grant Beaty
  ----- Original Message -----=20
  From: Mark=20
  To: List for general do-it-yourself EFI talk=20
  Sent: Friday, January 31, 2003 10:58 AM
  Subject: Re: [Diy_efi] Compressor "surge ring"


  I'm not entirely positive on this, but thought I'd throw it out there =
in case it helps ... It looks to me that it may be just that (an =
'anti-surge' ring) ...  I think it is just a venturi type of restriction =
aimed at increasing the incoming air velocity, resulting in an increased =
stangnant pressure and an increased Net Postive Suction Head (NPSH) .. =
resulting in less surge. .. the downside is that it is a restriction in =
the intake.  I think a better method of thwarting intermitent surge is =
to utilize an upstream intake plenum.=20

  Again, I'm just taking an educated guess on this and could be wrong.=20

  Regards,=20

  Mark=20

   Grant Beaty <gbeaty at ufl.edu> wrote:=20

    In the interest of turning this into a DIY_TURBO list ;) (The =
out-of-print
    books on turbos I've ordered still haven't gotten here...)

    Anyone ever see something like this:
    http://www.dsmtimes.org/images/products/fp305.jpg

    Someone at Forced Performance (DSM turbo maker, 2L engine) mentioned =
they
    needed this to prevent surge at boost >=3D 15 psi, at RPMs > 5000.

    Does anyone know exactly how this works, and if there are any =
drawbacks?

    Thanks for any help,
    Grant Beaty


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<STYLE></STYLE>
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<BODY bgColor=3D#ffffff>
<DIV>"...It is also possible for the surge to occur in the diffuser of=20
the<BR>compressor housing due to the dynamics of the system. In this =
case what=20
is<BR>called a ported shroud compressor housing is used. You might have =
seen=20
these<BR>on really big turbos. A ported shroud looks like a really big =
inlet bib=20
with<BR>the inducer bore of the housing inside it. Looking closer, you =
can see=20
an<BR>annular groove around the inducer of the compressor in the =
housing.=20
What<BR>this does is allow air to recirculate around the compressor =
wheel at=20
higher<BR>boost pressures, "fooling" the compressor into thinking it is=20
actually<BR>flowing more and helping prevent surge. This also costs you =
some=20
peak<BR>efficiency but preventing surge is much more important. Ported=20
should<BR>housings are useful in preventing surge at higher pressure=20
ratios."</DIV>
<DIV>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>I'm wondering if anyone has experiences =
with the=20
real-world gains (or losses) of one of these housings.</FONT></DIV>
<DIV><FONT face=3DArial size=3D2></FONT>&nbsp;</DIV>
<DIV><FONT face=3DArial size=3D2>Thanks,</FONT></DIV>
<DIV><FONT face=3DArial size=3D2>Grant Beaty</FONT></DIV>
<BLOCKQUOTE=20
style=3D"PADDING-RIGHT: 0px; PADDING-LEFT: 5px; MARGIN-LEFT: 5px; =
BORDER-LEFT: #000000 2px solid; MARGIN-RIGHT: 0px">
  <DIV style=3D"FONT: 10pt arial">----- Original Message ----- </DIV>
  <DIV=20
  style=3D"BACKGROUND: #e4e4e4; FONT: 10pt arial; font-color: =
black"><B>From:</B>=20
  <A title=3Dflamindakman at yahoo.co.uk=20
  href=3D"mailto:flamindakman at yahoo.co.uk">Mark</A> </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>To:</B> <A =
title=3Ddiy_efi at diy-efi.org=20
  href=3D"mailto:diy_efi at diy-efi.org">List for general do-it-yourself =
EFI talk</A>=20
  </DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Sent:</B> Friday, January 31, 2003 =
10:58=20
  AM</DIV>
  <DIV style=3D"FONT: 10pt arial"><B>Subject:</B> Re: [Diy_efi] =
Compressor "surge=20
  ring"</DIV>
  <DIV><BR></DIV>
  <P>I'm not entirely positive on this, but thought I'd throw it out =
there in=20
  case it helps ... It looks to me that it may be just that (an =
'anti-surge'=20
  ring) ...&nbsp; I think it is just a venturi type of restriction aimed =
at=20
  increasing the incoming air velocity, resulting in an increased =
stangnant=20
  pressure and an increased Net Postive Suction Head (NPSH)&nbsp;.. =
resulting in=20
  less surge. .. the downside is that it is a restriction in the =
intake.&nbsp; I=20
  think a better method of thwarting intermitent surge is to utilize an =
upstream=20
  intake plenum.=20
  <P>Again, I'm just taking an educated guess on this and could be =
wrong.=20
  <P>Regards,=20
  <P>Mark=20
  <P>&nbsp;<B><I>Grant Beaty &lt;gbeaty at ufl.edu&gt;</I></B> wrote:=20
  <BLOCKQUOTE=20
  style=3D"PADDING-LEFT: 5px; MARGIN-LEFT: 5px; BORDER-LEFT: #1010ff 2px =
solid">In=20
    the interest of turning this into a DIY_TURBO list ;) (The=20
    out-of-print<BR>books on turbos I've ordered still haven't gotten=20
    here...)<BR><BR>Anyone ever see something like=20
    =
this:<BR>http://www.dsmtimes.org/images/products/fp305.jpg<BR><BR>Someone=
 at=20
    Forced Performance (DSM turbo maker, 2L engine) mentioned =
they<BR>needed=20
    this to prevent surge at boost &gt;=3D 15 psi, at RPMs &gt; =
5000.<BR><BR>Does=20
    anyone know exactly how this works, and if there are any=20
    drawbacks?<BR><BR>Thanks for any help,<BR>Grant=20
    =
Beaty<BR><BR><BR>_______________________________________________<BR>Diy_e=
fi=20
    mailing=20
    =
list<BR>Diy_efi at diy-efi.org<BR>http://www.diy-efi.org/mailman/listinfo/di=
y_efi</BLOCKQUOTE>
  <P><BR>
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href=3D"http://rd.yahoo.com/mail/mailsig/*http://mailplus.yahoo.com">Yaho=
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href=3D"http://rd.yahoo.com/mail/mailsig/*http://mailplus.yahoo.com">Sign=
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  <P></P>_______________________________________________<BR>Diy_efi =
mailing=20
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