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Looking for suggestions for engine cooling

 
Old 07-01-2019, 11:07 AM
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Noahs944
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Default Looking for suggestions for engine cooling


The 944 I converted to turbo runs REALLY WELL but runs hot. I'm looking for creative solutions.

A contributing factor might be that I angled the rad on about a 45 degree slant and I'm running a front mounted inter cooler & AC condenser.
The more boost I run the hotter it gets (duh!), so I can start using the meth-water injection kit I installed for when boost is on.

I don't need to bring temps down a lot but a bit would help.
Things I've done to help:
-AFR 11.5-12.5:1
-Running 2 oem fans simultaneously
-Ducting or Air Dam in effect
-70/30 coolant/water ratio

Things I haven't done yet that I think will help: add batwing and seal up headlights with clear covers.
Am also considering cutting off the back ends of the factory fog light pockets & extending the air dam to those backsides.
Any suggestions would help, thank you.
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Old 07-01-2019, 11:12 AM
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Is there maybe an auxiliary coolant heat exchanger I can plumb in and mount remotely?
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Old 07-01-2019, 12:42 PM
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CyCloNe!
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Do you happen to have the 951 radiator in your car? That would help if not.
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Old 07-01-2019, 02:49 PM
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that is too high a percentage of coolant....way too high. the water is what carries the heat away and the highest percentage one would need is 63-64% of coolant to water if its -40F.

dump it and go with a 50-50 mix and your temps will drop.

wetters, like red line and royal purple stuff, decreases the surface tension of the molecules. most of the engine heat is around the exhaust port. heat transfer from the metal of the head to the liquid coolant is reduced when bubbles occur on the surface (nucleate boiling. heat a pan of water on the stove and you'll visualize it). the purpose of the wetter is to make the bubbles smaller, thus carry away more heat. note, some say the redline water wetter isn't compatible with g-11 or the blue coolant.

put a 20-21 psi (149kPa) cap on the overflow. a 100kPa isn't enough to keep it from boiling. same principle as above. small bubbles.
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Old 07-01-2019, 03:30 PM
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Originally Posted by thomasmryan View Post
that is too high a percentage of coolant....way too high. the water is what carries the heat away and the highest percentage one would need is 63-64% of coolant to water if its -40F.

dump it and go with a 50-50 mix and your temps will drop.

wetters, like red line and royal purple stuff, decreases the surface tension of the molecules. most of the engine heat is around the exhaust port. heat transfer from the metal of the head to the liquid coolant is reduced when bubbles occur on the surface (nucleate boiling. heat a pan of water on the stove and you'll visualize it). the purpose of the wetter is to make the bubbles smaller, thus carry away more heat. note, some say the redline water wetter isn't compatible with g-11 or the blue coolant.

put a 20-21 psi (149kPa) cap on the overflow. a 100kPa isn't enough to keep it from boiling. same principle as above. small bubbles.
+1 👍

Increasing the proportion of antifreeze (e.g. 30:70) does not lower the freezing point any further. On the contrary, undiluted antifreeze freezes at around ľ13░C and no longer dissipates sufficient engine heat at temperatures above 0░C. This would cause engine overheating

https://www.hella.com/techworld/uk/T...-coolant-2708/
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Old 07-01-2019, 03:43 PM
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Originally Posted by CyCloNe! View Post
Do you happen to have the 951 radiator in your car? That would help if not.
My rad is a 944 n/a rad (which I *thought* was the same as a 951 ). No?
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Old 07-01-2019, 03:45 PM
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Thomas, that is very interesting information!!
Where can I get a rad cap like this to fit the 944 overflow tank?
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Old 07-01-2019, 06:50 PM
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Late model 944 after 85 or 86 got the 21psi cap stock.

951 rad is about 3cm taller than NA and thicker too iirc.

You shouldn't need an aux rad in a climate like Alberta.
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Old 07-01-2019, 06:59 PM
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I typo'ed 149kPa..i meant 140. its what's on the 968 and most mid 90 Mercedes use them. pretty sure the 951 uses the higher pressure rating also.

less is more. try 50/50 but it might get slushy at -15C. mix the junk up before you pour it in. add a few liters of water then pour the antifreeze into the water jug and shake it up. keep the process up until you have a gallon(3.78L) of each in the system. premix another gallon for the bleeding and future leakage.

imho....air can get sucked into the system as the car cools through the fittings. I pump the system up with air with the system dry. if a hose fitting leaks/bubbles after misting it with soapy water, I seal it with hylomar until it holds air pressure. BUT, it always blows the head gaskets on my kids cars...lol
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Old 07-01-2019, 11:35 PM
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Old 07-02-2019, 01:31 AM
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Originally Posted by V2Rocket View Post
Late model 944 after 85 or 86 got the 21psi cap stock.

951 rad is about 3cm taller than NA and thicker too iirc.

You shouldn't need an aux rad in a climate like Alberta.
Good to know! Thanks Spencer.
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Old 07-02-2019, 02:52 PM
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Originally Posted by Noahs944 View Post
Good to know! Thanks Spencer.
Get the exact psi oem radiator cap. They are different psi ratings on different years and models. Bleed the air out. Bleed the air out and Bleed the air out again. Sometimes I drive a few days and bleed air out and drive a few days and do it again. And on and on. Til needle stays on white mark. These cars just wont bleed even at angle. It is a crazy mess to do it right.
Hours and hours spent on this through the years!

Also dont always (ever) trust the needle. Haha
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Old 07-02-2019, 04:13 PM
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Jay W,
The thermostat I'm using seems okay, it worked great as a NA but I think if it opened a bit sooner would help. It came with the 944online waterpump package (full kit) I bought some time ago.
Regarding the overflow cap, correct me if I'm wrong, but if I'm not experiencing a problem with the car puking coolant, then there's no need to change psi rating, right? It was puking coolant until I made the aid dam & wired up both fans to turn on together.
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Old 07-02-2019, 04:19 PM
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Originally Posted by CyCloNe! View Post
Do you happen to have the 951 radiator in your car? That would help if not.
Thank you for bringing this up. I should probably upgrade. Anyone know how much thicker the rad is vs n/a?
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Old 07-02-2019, 08:20 PM
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Your biggest issue in my opinion is the 45 degree slant of the radiator.
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