924Board.org

[Scorpio]

944 turbo radiator and expansion tank

Any thoughts or suggestions about running a water coolant line from the radiator to water pump outlet ---> Garret turbo---> electric water pump---> radiator hot side

The pump could be boost controlled in which Case will only be on during boost time... Other possible ideas are turbo temp controlled but how will this be done.... Or always on when engine on

Other considerations would be when thermo opens it will reverse flow possibly towards turbo and radiator cold side

If this idea doesn't work I'll be taking a water feed line from engine coolant transfer pile under inlet manifold
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1979 NA
MS1..EFI..
GARRETT T25 TURBO
BILSTEIN SHOCKS
GT BASED CUSTOM BODYKIT

Brisbane , Australia
Think mean think fast
all youll see is
my Porsches Arse!!!

[fiat22turbo]

On most factory water cooled turbos, the cool water goes in the bottom and the hot comes out of the top.

This way, the water can cycle on its own as it essentially percolates after shutdown. That is pretty much all water-cooling does for a turbo, provide extra cooling capabilities after shutdown, while running, the oil provides quite a bit of heat management.

Running a pump doesn't hurt and certainly would help cool more quickly, but on the factory Garrett's on my other turbo cars, they live to 150+K miles without much issue at 10-14psi without a blow-off or bypass valve.
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Stefan
1979 924 Carrera GTS (clone-ish)
1988 944 Turbo S (Silver Rose)

[Rasta Monsta]

Think about pump happiness while you are planning this. Both the turbo hotside and (I think) the line under the mani will be hotter water.

For the sake of longevity, I would find a cool supply to run through the pump.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[flosho]

I would just ditch the pump idea and plumb it w/o one.
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[This Space For Rent]

[musicalannette]

The place that going to get hot is the turbine side of the turbo, the temperature measurement there is critical if this is a non-standard setup. You need to know the EGT or Exhuast Gas Temperature. Its called TP or TailPipe temp on aircraft. If will be dependant on how hard you are pushing the turbine.

It does have a maximum recommended value and I would look into th max value for that particular turbo. Its probably around 600/650 deg C .If you exceed it you will melt the turbine itself. No amount of cooling water (unless sprayed into the engine or intercooler as charg cooling) or oil cooling will stop it from melting.

If you want to get special then you need to look into superalloys.
I dont know of any car manufaturers off the top of my head that use this type of material but im sure some will have looked into it.

http://en.wikipedia.org/wiki/Superalloy

The bearings run in oil and when you stop the heat can soak backwards from the turbine down the shaft and into the bearings, the water is there to try and get some of the heat away from the oil.

Your cooling system takes water from the bottom of the rad, through the pump into the engine though the thermostat, which when it opens, lets water into the radiator. there is usually a small bleed bypass from the engine around the thermostat for whne the stat is shut.

You want to plumb the turbo into the circuit between the rad and the pump or the pump and the engine (whichever is easier with pipes).


This means the waterflow will always be "on" but the waterflow will still be regulated by the thermostat, if you put too much energy into the cooling system you might have cooling problems (the radiator might not be able to cope, so you might have to fit a larger radiator), so keep an eye on the temp guage if you keep the same rad.

Hope this helps.
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I KNEW white wall tyres were invented by Americans .....just not at Boeing.... to be fitted on the 737.....