[BiturboS4] Todd from AWE

Scott stiles_s at hotmail.com
Tue Apr 22 18:45:41 EDT 2003

Good to see you here again, Todd.
Any guesses as to why they fail more in the S4tt application then they
appear to in either the 1.8t or A62.7tt installations?
I realize the 1.8t turbo is a slightly different design (although still a
K03), but I can't remember hearing about a single A6 or Allroad failure...


-----Original Message-----
From: biturbos4-admin at audifans.com [mailto:biturbos4-admin at audifans.com] On
Behalf Of Todd Sager
Sent: Tuesday, April 22, 2003 4:58 PM
Cc: biturbos4 at audifans.com
Subject: Re: [BiturboS4] Todd from AWE

Yes, still here though not checking in as often as I wish to.

The pump is triggered by a thermoswitch, which is a sealed unit.  I
suppose by doing some parts bin engineering, a lower temp switch could
be substituted, or bypassed altogether with a manual or external switch.

However, while an afterrun pump is certainly a good idea, it is not a
substitute for proper cool down procedure.  Running coolant through the
turbo will help drop temps, but the real problem is letting the turbo
stop spinning when still red hot.

Allowing the turbo to cool while idling keeps the turbo spinning during
this time (as exhaust gasses pass through the turbine), which prevents
an imbalance issue from occurring.  If the turbine is red hot and is
allowed to stop spinning, the shaft can distort from the weight of the
turbine wheel.

There is no conclusive evidence why the K03s fail as often as they do,
nor is there evidence that the "updated" parts have cured this.

The failures are as varied as compressor wheel damage, turbine wheel
failures, and seizing.  These can all be caused by overheating during
operation, improper oiling, or improper cooldown.

Our recommendation to customers is to either allow a 2-3 minute cooldown
at idle after high boost application, or a gentle no boost cruise for
1-2 miles before shutdown.  No question that this becomes even more
critical when increasing the boost with a chip.

"Marc A. Abernethy" wrote:
> Todd are you still on this list.  A couple of days ago we were
> discussing turbo timers and the Audi after-run pump.  Are you guys at
> AWE able to come up with a new thermostat for the S4s after-run pump?
> So it will come on at lower temps.  This seems like it might be simple,
> then again I have no idea to to it.
> Any thoughts?
> Marc
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If you have any questions, please do not hesitate to contact me.

Todd Sager
A.W.E. Tuning
Orderline 888-565-2257

Be sure to check out our latest ad in the April issue of European Car

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