92 turbo 5spd intake chimney question?

[ciper]

All of us should agree that as gases cool they take up less volume or drop in pressure. Less pressure before the turbo means less energy to spin the turbine. Some will argue the difference is not enough to matter. We should all also agree that less heat in the engine bay increases reliability.

I think the ONLY argument against insulation are the fears of cracking. Personally I have never seen it happen. Does anyone know the cause? Is this only with cast iron parts? Intuition would tell me that a wrapped piece is less likely to crack since the temperature changes are more gradual.

[SubaruNation]

I couldnt get my turbo to get that hot after a very long run up a very steep hill... huh...

+1

[Steeper]

I would worry less about the turbo cracking and more about the oil cooking inside the turbo. When I get my turbo to glow, and it does everytime I go home (kelowna to big white, about 4000 foot climb in 30 minutes or so at WOT and 12 PSI most of the way) I have to take her easy for the last few minutes of my drive, which is hard 'cause my favorite corners are 2 hairpins minutes from my house, or idle for a bit at home. I kinda feel like wrapping my turbo would prolong both of these techniques of cooling the turbo...

[ciper]

Steeper and others: This is why many people use Turbo Timers. They keep the car running for a certain amount of time after a hard run without needing the key in the ignition and the doors can be locked.

[Steeper]

oh I know, I just dont have one, so I do it the old fashion way, by sitting in my driveway for 5 mins. I also use Mobil 1 and change it frequently.

[SubaruNation]

ok ciper, i thought our cars had some cooling technique that worked almost the same, so you dont need one (UNLESS YOU ARE RACING F1 BB) <---- just to make sure

[Steeper]

well our cars have one advatage over alot of other turbo cars, a tubular exhaust manifold. Cars with a cast iron manifold, that weighs a ton need turbo timers alot more than ours because that manifold holds so much heat in it that it will keep the turbo hot for alot longer. that said, its really only in everyday not hard driving hat we can get away with shutting her down right away, if you are on the gas makin boost/power, for the love of god let your turbo cool off for a few minutes, either a couple blocks of real easy driving or idle for a few minutes at your destination.

[ciper]

Subarunation: Now that you mention it I do remember something about the coolant routing that would keep the turbo cool after the engine was off... I think it was on this board somewhere we talked about it.

Either way I still say multiply the amount of time you were at full throttle by 8 and count 1-1000 2-1000 when you stop.

[SubaruNation]

cool i'll do that