924Board.org

[JjyKs]

Does anyone have an idea how the water actually flows in our system?

I made this bad picture. I'm trying to find points to mount flanges for turbos water in/out. Only "problem" is that there are 3 tubes on the pump. Blue one comes from the back of the head/heater core and goes to the head from the purple port and then there's the thermostat on the brown tube. Should i mount the turbo inlet on the blue (or brown?) and outlet on the green pipe?

[ideola]

None of the above.

The ideal solution would be to just mount a completely separate water circuit just for the turbo. This could be accomplished fairly inexpensively with an electric pump, a small heat exchanger about the size of the OEM 931 oil cooler, some hose, a few clamps, and a basic relay/wiring arrangement.

The next best solution would be to mimic the 951 setup, which has an extra port on the cold side of the radiator and an extra port on the expansion tank. You could emulate this without modifying the stock radiator or expansion tank by cutting the OEM hoses and installing some tees. The feed line should come off the lower radiator hose (cold side of the rad) using a tee. Run that to the electric pump, putting it at the lowest point in the system. Run the return line back to the expansion tank, and tee it in to the main feed line that goes into the tank.

I would absolutely NOT recommend relying upon the stock mechanical water pump.
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erstwhile owner of just about every 924 variant ever made

[Rasta Monsta]

I would skip the whole thing. Many people run K26 units dry. The most significant purpose of the water jacket is to mitigate damage done by idiots who flog their cars and shut them down without proper cool down.

K26 was designed to be oil cooled, which works fine if you run it properly. There is no advantage while the engine is running, just one additional system to maintain. If you don't wire it with a timer to run the pump after shutdown, the whole endeavor is pointless.
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Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[JjyKs]

Rasta:

Skipping water lines completely it isn't an option since I'm running a freshly rebuilt GT17 instead of K26 which is famous for being pretty weak turbo that absolutely needs water cooling. Gonna swap it to Mitsubishi TD04 at some point like the Saab guys do to get it more reliable, but since it was literally almost free from the guy I purchased my megasquirt from I decided to use it for a while.

ideola:

Thanks for the tip. I was somehow under the impression that electrical pumps wouldn't be safe option but if that's how it's done in the 951 i think that it would be a feasible option.

Anyone has an idea about some "regular" car that has an electric water pump? Porsche parts are quite hard to get here in Finland without ordering and waiting for 1-2 weeks so something from a regular Toyota/Mercedes or something else would lot easier to find. Aquarium pumps aren't proparly meant to operate at these temperatures..?

[ideola]

Use the Bosch 0 392 022 002 auxiliary electric water pump. It is designed for this purpose and should be readily available in Europe. This is the unit that I included with my Top Mount Charge Cooler kit.


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erstwhile owner of just about every 924 variant ever made

[gerben1986]

[JjyKs]

Thanks guys. I some BMW auxiliary pump that had this basic Bosch connector. Right now i temporarily mounted some marine pump I had lying around that should handle high temperatures, pressure and continuous usage as well. Gonna change it to the BMW one at some point though.

[Rasta Monsta]

Bilge pumps don't like hot water... btdt.
_________________
Toofah King Bad

• WeiBe (1987 924S 2.5t) - 931 S3

[JjyKs]