Has anyone made ducting under the bonnet for airflow to cool the turbo? If so did it make much difference?
Nope. I toyed with it, but you want the hotside to stay warm, it`s the cool side you want to keep cool. Are you concerned about radiant heat ? If so, I`d look for a Turbo Blanket.
It's not heat while running that kills a turbo it's heat soak after its stopped running that does the most damage
^ Which is why you should idle down, let the oil and water take the extreme heat away You don't really want to blast cold air on to a hot turbo, the temperature across the unit will be uneven, for a start Blankets work well, as do simple shields to stop the radiant heat
the higher power 20v lumps have a relay to run on an aux waterpump after engine switch off, though obv this is only of any use on water cooled turbos the mk2 rad fan after-run relay could be used for the same effect, or if its in a mk3 golf swap a VR6 fan control unit in there and add wiring to the pins for the 6 pot electric waterpump
I ALWAYS do a cooldown lap (unless the session is red-flagged) then leave it idling in the paddock with the cooling fans running for several minutes before switching the engine off. With a Turbo car, it`s the only way.
