[200q20v] intercooler

Brian Link brianl at starsys.com
Mon Dec 3 08:53:52 EST 2001

Thanks Bernie,

Has anyone done some datalogging and read either the inlet air temp sensor
or the mass air sensor.  I'm just trying to run some numbers on 1.  how
hard im pushing the k-24, and 2. what are the other turbo options.  Scott J
made a comment on the S-car list that there is 100% failure rate on the
k-24 above 2.4PR (Is this True?).  I calculate that I'm at 2.6-2.7PR up
here in Colorado, sea level folks with chips are at 2.4PR.  Could anyone
that has had a k-24 fail chime in of the how's and whys of the failure?

Thanks in advance
Brian Link

-----Original Message-----
From:	Bernie Benz [SMTP:b.m.benz at prodigy.net]
Sent:	Sunday, December 02, 2001 2:44 PM
To:	Brian Link; Brett Dikeman; Scott Justusson
Cc:	200q20V mailing list; audi-20v
Subject:	Re: [200q20v] intercooler

Brian and Brett,

No simple answer to your complex question.  To really quantify IC
effectiveness you must specify and control many test conditions, such as:
Temperature and mass flow of cooling air, relative to ambiant.
Mass flow, temperature and pressure drops across the IC of turbo output
all relative to ambiant.
Steady state or specific transient, heat sinking conditions.

I agree with Brett, that Audi ICs are better designed, on an effectiveness
per unit volume basis, than are most expensive aftermarket ICs.

Here are some design details of the Audi S5 ICs that I have quantified:

The 200-20V ICs have an effective core length of 15", the 5Ks are 13.5",
just considering cores, not header controled flow patterns.
The cross sectional area and internal heat transfer designs are identical,
they are the same core, differing only in length.
The open flow CSA I have measured as being 6.2 square inches, twice that of
2" ID inlet piping @ 3.14 sq ", which seat of the pants wise, seems a
reasonable ratio, flow and pressure drop wise.

For my "3Bing the 7A" project, I have elected to use two 5K cores in a
single pass series configuration, for cost considerations and because the
only possible space in the 90Q is low, behind the bumper where the IC can
see ram air from the full width air vent under the bumper.  With fogs gone,
the IC will share this full width vent with the oil cooler.  The plastic
headers have been modified for single pass use, and the return air piping
will be integrated into the chassis cross brace, ala the RS2.

The two cores were combined by first swaging the inlet side of each core
tube end opened, such that the outlet tubes of the first section slip into
the inlet tubes of the second section, for no flow disturbing transitions.
The mating tube plates were then welded together around their periphery and
the modified headers reaattached.  I have the swaging tool, if any one

To quantify the effectiveness of this IC installation, I intend to install
temperature and pressure sensors either side of the IC.


> From: Brian Link <brianl at starsys.com>
> Organization: Starsys Research
> Date: Tue, 27 Nov 2001 14:15:36 -0600
> To: "'200q20v at audifans.com'" <200q20v at audifans.com>
> Subject: [200q20v] intercooler
> Guys, Do any of you have a value for how much the stock intercooler
> I'm looking for a rough ball park inlet/outlet temperature readings.   Or
> even better has someone pulled out mass flow values from the mas via the
> VAG or similar?
> thanks

> Brian
> From: Brett Dikeman <brett at cloud9.net>
> Date: Wed, 28 Nov 2001 02:18:40 -0500
> To: Brian Link <brianl at starsys.com>, "'200q20v at audifans.com'"
> <200q20v at audifans.com>
> Subject: Re: [200q20v] intercooler
> At 2:15 PM -0600 11/27/01, Brian Link wrote:
>> Guys, Do any of you have a value for how much the stock intercooler
>> I'm looking for a rough ball park inlet/outlet temperature readings.
>> even better has someone pulled out mass flow values from the mas via the
>> VAG or similar?
> Sounds like you're looking for the efficiency rating and pressure
> drop.  A search of the archives might turn up something.  It is, all
> things considered, a pretty big unit, vastly superior to the
> double-pass units in 10v cars, and the placement is pretty
> good...lots of airflow through the front there.  A few people I've
> discussed it with have said "nah, don't bother, it's fine for some
> pretty high HP levels."
> I've thought about the subject at great length, and there just
> doesn't seem to be much extra room in any particular direction; as
> is, the grille practically kisses the IC.  The only easy gain would
> be to find a unit with better efficiency/lower pressure drop.
> Keep in mind that a IC that lets more air flow through the outside
> surface may affect the engine in other ways.  Ask someone like Eric
> Fletcher, he seems to know quite a bit about aerodynamics in that
> area(he once explained to me why removing the hood seal at the back
> of the firewall would be a bad idea; turns out that's a high pressure
> area, not a low pressure area like one might think.)
> B

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