Re: More IC stuff

["Scott M." <scottmo@teleport.com>]

Turbo Meisters,

Here is some Intercooler data to chew on, don't know if the
results are good, bad or indifferent, I will let the turbo
"enthusiasts" comment. Car under test, 1989 200TQ,  Dual
Knock sensor MC engine, K24 turbo, stock intercooler/turbo
etc. Ambient air temp 43F, test run done in 4th gear from
2500RPM to 6300RPM, (~115MPH max) ~1.8 bar boost produced
in the upper RPM range.

A thermocouple was mounted in the intercooler inlet to
measure the temp of the air exiting the turbo and another
thermocouple was mounted in the intercooler exit where the
accordion hose is. The temperature meter was set to record
the maximum temps recorded. After the banzaii run, Turbo
exit max temp was 210 degrees F, intercooler exit max temp
at 85 (Delta temp between intercooler inlet/outlet 125F)
According to the Corky Bell math exam, this would be a
intercooler efficiency of ~76%. 

One point of interest, the Dual Knock Sensor MC engine is
reported in the 1989 Audi Tech literature to have a "New
turbo intercooler with improved air flow", not very
quantitative......

I'm not sure which Audi intercooler test Scott J. was
referring to, but I took another look at the SAE article
#860103 which describes the 1986 5000TQ turbo engine and
they did a high speed intercooler temp test at full
throttle, 5th gear, Ambient air temp = 20C (68F). The
intake manifold air temp rose slowly to the peak temp at
230kM/h (143MPH) where it was ~38C (100F). 

The same 5th gear WOT test indicated the delta temp between
inlet/outlet of the intercooler and the pressure drop. At
~6400RPM/5th gear  they found the delta temp to be ~52C,
(125F), this would indicate a turbo exit temp of ~225F.
Intercooler efficiency = ~80% The pressure loss in the
intercooler was shown to be ~145millibar, which according
to my calcs is about 2.1 psi. 

My copy of this article sucks so others may want to check
my figures as the fine print is tough to read. One thing
that is a bit odd in this test, is the top speed shown at
143MPH, my understanding was the '86 5000TQ was only good
to 130-135MPH with the 162HP MC, I wonder if the Euro
version with ~185 HP was actually tested......if it was,
the max turbo boost may have been ~1.6 bar and not the
lousy 1.42 Bar found in the US version. 

Well, those are a few data points, looks like someone needs
to do a  intercooler temp test at speed using 2.0 bar of
boost.

Let the games begin! Be careful where you stick those
thermometers.....

I will scurry back to my cave....to make some more
measurements........next step is to get some pressure
transducers setup to measure the pressure at the air filter
intake, turbo intake, turbo exit, intercooler exit and
intake manifold. Oh what fun........

Cheers
Scott M. 
TempTakinPsiSniffinDude