[s-cars] Max. Boost Question

[Kaklikian, Gary]

Calvin,

A K26 will run efficiently at 18-20psi even at this altitude. The turbo and driveline are not the problem. The problem with the 10vt engine is the CIS fuel system, intercooler, exhaust, etc, nothing internal to the motor.  I ran my ex-4000 with a K26 Sport at 16 psi here regularly using an electronic boost controller, but it had an upgraded downpipe/exhaust, intercooler, extra injectors, custom chip, etc, etc.  18-20psi was possible with race fuel.
By comparison, my S4 with only a stage 1 chip overboosts to 21psi, a scary pressure ratio for a puny K24 at 6000ft. But it will only maintain 16psi, and the knock sensor will do its thing on a warm day unless I use 93 octane.

Gary Kaklikian
'92 S4
'89 951


From: "Calvin & Diana Craig" <calvinlc at earthlink.net>
To: "S-car list" <s-car-list at audifans.com>
Date: Mon, 13 May 2002 21:45:48 -0600
Subject: [s-cars] Max. Boost Question

This may be a little off-topic since it isn't for an S4 but this is the most
knowledgeable group I can think of for this question.  I was wondering if
anybody knows why the chips for the 10 valve engines only max out at about
1.8 Bar, where all the 20 valve chips stage 1 starts at 2.25 Bar and things
just go up from there.  Since my specific question involves my early '89
wagon with the 7.6 CR and K-26 turbo I certainly don't see any limitation
driving this from the turbo or the CR of the engine.  Is the CIS injection
not up to the job?  Is the head gasket weaker??? (I doubt it).  Is the
intercooler not able to handle the extra boost effectively?  Driveline??? I
am interested in chipping the car and wondering if anybody makes a 2.0 Bar,
or so, chip for it?  Thanks.
--Calvin Craig
Parker, CO
'92 S4
'91 200 TQ
'89 200 TQW
'72 Formula Firebird



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