[s-cars] Cold Air Intake Mod Reduces Turbo Temp

[Tony Curran]

Here is what may be considered un-scientific results of air temperature
measurements of air flowing just behind the turbo before and after cold air
intake mod. For the mod, the OE intake hose was removed leaving an increased
airflow path from grill to turbo. Also temperature of air scooped in is at
lower temperature (heat from engine does warm up OE scoop). A NTC thermistor
was mounted on the oxygen sensor cable protruding in to air space just
behind turbo and wastegate and wired to ohm meter in cabin - the lower the
measured resistance, the higher the temp (same device used for both tests).

Test conditions:
The measurements were taken on the same stretch of road at roughly same time
of day with approx ambient air temp: 16 deg.C +/- 1 deg.C (1450 ohms :
1000ohms at 25 deg.C). The speed was set via cruise control to 115km/h.

Results...

Measurement Time	Before Mod	After Mod
Start			779		694
10 mins		605		666
14 mins		602		640
22 mins		550		676
25 mins		670		714

The results suggest that the additional air flow over the turbo/wastegate,
due to OE intake hose being absent, reduces the operational temperature of
the turbo. I know, not enough samples to be conclusive, but indidicative?

I plan to place a shield over the exposed air intake hose from the MAF to
direct more air towards the turbo to see if this further changes the
temperature characteristics and also prevent turbo from heating that hose.
BUT this is unlikely to happen before car is MRC'd this weekend.

Food for thought...

Tony
96 S6