Audi Turbos...Something a friend forwarded to me
07-25-2001, 09:22 AM
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Audi Turbos...Something a friend forwarded to me
Save your money. For more on turbo heat soaking, read SAE 880258 (The
development of a Severe Turbocharger Bench Engine Test) and specific to
the WC Audi turbos, SAE 860103 (The Third Generation Turbocharged Engine
for the 5000CS and 5000CS Quattro).
In 860103 Fig. 9, the measure of piston rings and temp of turbo center
bearing are measured Temp (100-400C) v Time (0-10min) after shutdown.
Without watercooling (NWC) of the turbocharger unit, at 0 time piston ring
temp was 260C(500F), the 1min post heat soak temps of piston rings
approached 400C (752F) and tapered to 280C (536F)@10min. The (NWC) Turbo
Bearing 0 time measured 140C (284F), then rises to a peak of 255C(491F)
@3min and measures 240C(464F)@10min. That's hot, now let's look at the
results with the Audi Afterun Water Cooling.
Comparing this to Watercooled Turbo center section (WC) with afterun the
piston ring shut down temp @ 0min was 190C(374F) dropping to 170C
(338F)@20sec and to 130C(266F)@10min. The turbo center section measures
125C(257F)@0min, rising to a peak of 150C(302F) and tapers to
110C(230F)@10min.
What does this all tell you? That Audi makes one of the best post shutdown
afterrun systems in the industry, straight from the factory. *All*
turbocharged Audis have this turbo cooling afterun system since 1986.
Bottom
Line: make sure the afterun circuit is functioning properly (the fan
should go to level 1 and the pump should start within a few seconds of
shutoff), and save your aftermarket "turbotimer" money for a good set of
gauges.
development of a Severe Turbocharger Bench Engine Test) and specific to
the WC Audi turbos, SAE 860103 (The Third Generation Turbocharged Engine
for the 5000CS and 5000CS Quattro).
In 860103 Fig. 9, the measure of piston rings and temp of turbo center
bearing are measured Temp (100-400C) v Time (0-10min) after shutdown.
Without watercooling (NWC) of the turbocharger unit, at 0 time piston ring
temp was 260C(500F), the 1min post heat soak temps of piston rings
approached 400C (752F) and tapered to 280C (536F)@10min. The (NWC) Turbo
Bearing 0 time measured 140C (284F), then rises to a peak of 255C(491F)
@3min and measures 240C(464F)@10min. That's hot, now let's look at the
results with the Audi Afterun Water Cooling.
Comparing this to Watercooled Turbo center section (WC) with afterun the
piston ring shut down temp @ 0min was 190C(374F) dropping to 170C
(338F)@20sec and to 130C(266F)@10min. The turbo center section measures
125C(257F)@0min, rising to a peak of 150C(302F) and tapers to
110C(230F)@10min.
What does this all tell you? That Audi makes one of the best post shutdown
afterrun systems in the industry, straight from the factory. *All*
turbocharged Audis have this turbo cooling afterun system since 1986.
Bottom
Line: make sure the afterun circuit is functioning properly (the fan
should go to level 1 and the pump should start within a few seconds of
shutoff), and save your aftermarket "turbotimer" money for a good set of
gauges.
07-25-2001, 09:42 AM
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No the coolant "gauge" never rises above normal
The guage is not really an acurate reprentation of what the temp of the coolant realy is.
Anyway if the coolant temp rises signaficantly the aux fan will turn on. The biggest heat spikes are durning stop and go traffic with the A/C on, duh, or after shutdown.
Anyway if the coolant temp rises signaficantly the aux fan will turn on. The biggest heat spikes are durning stop and go traffic with the A/C on, duh, or after shutdown.
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07-25-2001, 09:55 AM
#10
cooldown time
Possibly, if you're properly letting the car cool down after hard driving (as you probably are), there isn't a need for the fan to come on after you shut down the car; it's already cooled down below the threshhold.
Just a guess.
Just a guess.