CIS turbo power/boost limits

[Q]

Jukka & all.

I think the folks have several articles mixed together.

Using a stock turbo. . . I could easily get about 18 to 19 psig with
slightly lower control pressure.  Two European car articles were done with
good gas 104 octane. (artistic license or something)

I tweaked some things to get the 2.4 bar.  Yes things were stressed and a
little hot, but race gas is like an insurance policy.

On a turbo coupe with a 20V CIS head I've even seen 30 psi and severely
heated air using a stock turbo.  Yes the compression was 5.5 to 1, a
Colorado Car.  It could do a 4 wheel smoking start and leave a sport Q (Oh,
all right for only the first 500 feet)


On Carl Jerritts car there was an RS2 turbo
Some Mercedes injectors with increased fuel pressure (shim method)
16" x 16" x 3" intercooler
and other stuff I can't remember now.

We saw 25 psig briefly several times (I didn't want to push someone else's
car) when Carl & I were playing at Second Creek, outside of Denver with Karl
Baehre of Prestige Audi.

Audi Sport had, but no longer available, an air meter with a donut around
the sensor plate to change the air flow.  I've used it also for about 320ish
hp on the turbo coupe cars.  When I bought mine I think they had 4 left.

Now that I think about it I bought it back from the guy when he installed a
AAN engine.  It must be around somewhere.  It delevers so much fuel that you
have to use a control pressure regulator from a VW that is set for about 94
psi or the engine drowns in fuel.

The Rally Version used Bosch B 438 105 255  If you can find one they are
worth new $2200.00 US

Ned

-----Original Message-----
From: quattro-admin at audifans.com [mailto:quattro-admin at audifans.com]On
Behalf Of Jukka Majanen
Sent: Sunday, August 19, 2001 10:02 AM
To: Audi
Subject: Re:CIS turbo power/boost limits


Hi

Michael Gough <mdg3369 at mac.com>
wrote:

> ...Anybody have any BTDT with the 5kt cars knowing
> how much boost the stock fuel injection is good for?
> I may want to run the stock turbo fuel system on
> my next project for a wile before I upgrade to EFI...

I have used 2.2 Bar (absolut) max. charge pressure
on my ´90 10v MC-2 engine without problems.
That car has stock CIS.

I measured the A/F-ratio by O2-sensor voltage and
there seems to be ~800mV ( ~13.0:1 ) at full boost
( ~2.2 Bar/3500rpm ) and it remains to the max power
( +1.9 Bar/5500rpm ). Those restrictive exhaust parts:
header and K-24 seem to lower the pressure at the top?

Looks that CIS is capable to 2.4 Bar as Ned wrote.
When I was testing the car at that ( with our Euro 98
octane gas ) detonation made me to slow down and
readjust it to 2.2 Bar.

best
j-pm