View Single Post
copbait73 copbait73 is offline
Registered User
 
copbait73's Avatar
 
Join Date: Nov 2003
Location: Chesterfield IN
Posts: 1,314
Garage
Quote:
Originally Posted by 911st View Post
Question.

What is or what should we expect from an 'anti surge' style compressor?

I suspect compressor maps are without any undue restriction before the inducer.

Should we change or expectations when looking at a compressor map for a CIS 930?

With the restrictive metering system such maps should be optimistic it would seem?
Turbocharger compressors are tested to rigid industry standards on a laboratory gas stand.
Anti-surge compressors effectively broaden the map. For the Porsche, and most gas applications, this means the engine will operate in areas of higher efficiency through a broader engine RPM range.
Anti-surge was developed in the late 80s for modern diesels having electronic control of injection, primarily so they could operate at higher altitudes without going into surge.
Intake restriction can be accounted for in your "atmospheric conditions" portion of the P.R. calculations.
Regarding testing with actual vehicle inlet and discharge manifolding, I was part of doing this 36 years ago (GM Vega pull through compressor with Holley progressive carb) and a unique map" was generated. However, since then I've heard of no one in the turbo industry having any interest to do so.
That said, I learned on my first homegrown turbo application analytical compressor matching and actual operation within the engine system described by the manifolding, can be wildly different.

Last edited by copbait73; 02-02-2010 at 01:07 PM..
Old 02-02-2010, 12:44 PM
  Pelican Parts Catalog | Tech Articles | Promos & Specials    Reply With Quote #12 (permalink)