[s-cars] Max. Boost Question

[Calvin & Diana Craig]

Eric,

I think I may have been misunderstood a little.  The 1.8 Bar is absolute
pressure, so we are talking boost of around 12-15 psi.  Certainly since the
S4 comes with more boost than that stock with a k-24, the k-26 can handle as
much as the k-24 on the same size engine, right????
--Calvin Craig
Parker, CO
'92 S4
'91 200 TQ
'89 200 TQW
'72 Formula Firebird


-----Original Message-----
From: Eric Fletcher S.O.C. [mailto:steadi at attbi.com]
Sent: Monday, May 13, 2002 10:40 PM
To: Calvin & Diana Craig; S-car list
Subject: Re: [s-cars] Max. Boost Question


On 5/13/02 8:45 PM, "Calvin & Diana Craig" <calvinlc at earthlink.net> wrote:

> 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.

2 problems, your outta flow at 2.0bar on a stock K26 Not just compressor
flow but you can't get the exhaust out of that small housing. Then there is
the problem of the CIS starting to run lean.

Now you can get big Horsepower from the low compression engines but it does
require replacing some parts. You can go the way that I did on my old '87
5KCSTQ and put a hybrid turbo on it that has a K27 cold side that could make
700cfm at 2.4bar (And we were STILL efficient there) and then put a bigger
hot side housing on the K26 turbine. Then you massage the fuel system with a
few parts. A better intercooler (Less restriction mainly). A few other parts
here and there and your looking at 300Hp and beyond, REALLY Beyond.

The driveline doesn't become a problem till 475HP when you start to twist
input shafts.

Oh those mods... Make the car REALLY, REALLY Fun to drive.




Eric Fletcher
Former Pro Racer
Race Instructor
'00 S4tt
Abt K04 Turbo Conversion
RS4 Downpipes
Miltek Exhaust
RS4 Flywheel/Clutch and Pressure plate
Abt Z6 18x8 Wheels
Euro Headlights
and all sorts of other toys...