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Tigger937 · Joined: 11 Apr 2004 Posts: 914

What kind of upgrades are folks doing to improve engine cooling (ie., radiators, fans, oil coolers, etc.) and how effective are they? I've done some searching on this in the archives and haven't been able to find a whole lot.
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1981 931 (Concours)
1982 931 (Daily Driver)

"Think outside the box"

924RACR · Posted: Fri Feb 17, 2006 11:27 pm Post subject:

I haven't played with the turbo in this way, but rather with my NA racecar - oil cooling is huge. Of course, the 931 already includes... my first upgrade would be a bigger oil cooler swapped in for stock. The stock one isn't exactly huge.

I also had to upgrade my radiator; had it recored by a rad shop with a thicker core mated to the stock endtanks. Very convenient, works very well (though the brackets have sorta popped loose - that's another issue, installation). Not cheap - nearly $400 as I recall. I've heard of some fitting 944 radiators; might be easier or cheaper than what I did.

Cooling fan - stock ones are SO heavy and take up so much space!!! I replaced on the racecar with only 1 slimmer aftermarket SPAL fan, about $40-60 IIRC, and far lighter, leaves a lot more space in the engine compartment. I'd probably want 2 for a street car, but 1 suffices for a racecar.

That's all I've needed to do, that I can remember. Well, actually, you can also achieve some gains by sealing up around the radiator (gaps around the edges) to ensure that all the air coming in up front goes through the rad - that's a free efficiency boost.
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Vaughan Scott
Webmeister
'79 924 #77 SCCA H Prod racecar
'82 931 Plat. Silver
#25 Hidari Firefly P2 sports prototype

numbbers · Posted: Sat Feb 18, 2006 11:43 am Post subject:

First and easy mod, is to go to the lower temp fan temp sensor. I tried the recorred radiator from Performance Products ($400) with little to no improvement. Then I picked up a 951 aluminum radiator and fans off of Ebay for $100. Big Improvement.
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1980 924 Turbo

emoore924 · Joined: 13 Apr 2004 Posts: 2815

I converted to a 944s rad and it made a big difference. Some converting had to be done to the hose setup but it has worked very well for more than 10 years. I have a low temp fan switch and thermo (you need to change both if you change one). And, at the same time, I changed to a dual fan setup and rewired so both fans run on hi speed when they're running.

macBdog · Posted: Sat Feb 18, 2006 5:53 pm Post subject:

Ive installed a cooler thermostat, had the radiator reconditioned and switched to the 2 fan thermo setup. Made a good differance, temp is fully under control.
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1979 931 with a 350 chev
1973 911E with EFI

simsport · Joined: 06 Nov 2002 Posts: 573 Location: UK Warrington

I fitted a davies craig elec water pump. It gives better cooling flow than the stock pump plus saves weight and uses less power.

Cheers
Simon
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Blown is always best!

macBdog · Posted: Sun Feb 19, 2006 8:06 am Post subject: Re: Cooling

D Hook · Joined: 02 Nov 2002 Posts: 3156 Location: Omaha, NE

I would really like more info on this setup, when you have time.

Thanks!
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'80 924 n/a SOLD

bass gt · Posted: Wed Feb 22, 2006 12:01 pm Post subject:

Guy's,

I have the same set up. It's eay peasy. The Pump sits in the lower pipe that runs from the rad to the original water pump. You then remove the impeller from the pump and weld over the shaft hole which mounts the pulley wheel. Then you wire the pump up and hey presto. One MAJOR advantage over the mech pump is that above 3k rpm, mech pumps tend to lose efficiency, ie they start cavitating. So what you get is lots of bubbles being forced around. With the electric pump, there is a constant feed of water, regardless of engine speed. There is also a variable contrlooer available, which fine tunes the pumps operation. As the sensor measures the water temp, the pump is sped up or slowed down accordingly.
Oh, and try turning your water pump pulley by hand. You are saving that power staright away. Probably 2-3hp in lost energy.

Regards,
Steve

macBdog · Posted: Wed Feb 22, 2006 12:31 pm Post subject:

Damn this sounds great. What is the flow rate/diameter of your pump? Or any other important details...
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1979 931 with a 350 chev
1973 911E with EFI

Paul · Posted: Wed Feb 22, 2006 1:20 pm Post subject:

Bet you can find it here:

http://www.daviescraig.com.au/main/display.asp

Looks like he does business out of Leadfoot's home town...
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White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Paul · Posted: Wed Feb 22, 2006 1:26 pm Post subject:

Bass GT did you have to remove the thermostat as indicated at the web site?

If so how long does it take the car to warm up? I assume if you used the controller the pump runs very slow until the car warms up?

Did it effect the heater output?
_________________
White 87 924S "Ghost"
Silver 98 986 3.6l 320 HP "Frank N Stein"
White 01 986 "Christine"
Polar Silver 02 996TT. "Turbo"
Owned and repaired 924s since 1977
Porsche: It's not driving, it's therapy.

Dans931 · Joined: 20 Jan 2006 Posts: 45 Location: Baltimore

I have been told that the gigantic washer fluid tank blocks some of the airflow behind the oil cooler. I removed this on my 82 and replaced with a much smaller tank. If you don't use the A/C, remove the condenser. This will help. The fan switch and thermostat changes made a big difference in my car. Having the radiator professionaly cleaned also helps alot and is not expensive if you remove it and take it in.
Daniel

bass gt · Posted: Wed Feb 22, 2006 7:12 pm Post subject:

Paul,

Yes, the thermostat has to come out. However, with the controller unit the temperature control is much better.
Regarding the heater, as my car is a pure racer, no heater in there, so no idea about output.
My car warms up pretty quickly, but it always does that sitting still

Other than that, i think its well worth looking into.

Regards,

Steve

Smoothie · Posted: Thu Feb 23, 2006 2:34 am Post subject:

I'm trying to visualize the coolant flow with this setup and it looks to me like you'd also need to block off the flow into the top of the gutted mech water pump. Did you do something like that as well? Even with that, if/when the elect pump shuts off, you'd have no flow through the engine (the mech pump at least recirculates continuously through the engine whether the thermostat is opened or closed) (or does the elect pump run continuously, only slowing down and speeding up as needed?).
Without having the upper inlet to the mech pump blocked, I see most of the flow looping around from elect pump up through mech pump, to thermostat housing, through the radiator and back down to the elect pump, with lessened flow through the engine. (Haynes Pg 59) Also something tells me the flow through the heater would be affected, making the gutted mech pump approach less than wonderful for use in for colder climates.
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"..it's made in Germany. You know the Germans always make good stuff."

'82 924T, US version, dark green metallic, 5 speed Audi 016G gearbox