George D

None taken. This is good information shared, reason I'm here. Sometimes the "few" idiots chap my *** though.

Vehicle speed, not fan speed, nor a mechanical issue. I know it's a CFM fan pull issue using the stock fans with a 3.5" vertical FMIC, much larger than stock Griffiths condenser, then a Ron Davis radiator with two rows of 1" tubs and the stock fans isn't a good combination without vehicle speed. Cap is fine, and there is nothing blocking air flow.

I'm going to do a citric acid flush to make sure there's no build up, but the water is clean and the voltage reading of the coolant cold and after thermostat is open reads .06 which is about as low as you'll get using a multi meter using the 2v scale.

I'm calling Ron Davis tomorrow, as they used to manufacture fans with their 944 bolt in radiators. Stopped doing this from lack of demand. When you order one from them, it's built, not sitting on the shelf. They will know exactly what's needed, and likely build one for me.

You guys interested in a group buy? These will likely also work with the stock radiators, as mine attaches exactly as stock. Ron Davis uses SPAL fans, and the pic shared has a CFM of 3430.

Anyone know what the factory fans CFM is? I can't find this data.

The picture of the front of my car doesn't show all the work done to the frame for additional air flow and strength.

I need higher CFM fans, and that's just the facts.

Tom M'Guinn

ok, strike that then.... I've always wanted to check the RPMs on my fans to see if the circuit is slowing it down more than intended, and to see if new resistors and an iceshark style harness to the fans would speed them up. There has to be some reason why some folks seem to keep cooler than others even with all new parts-- recall Hosrom in Dubai who swore his gauge remained cool even in the extreme temps of the desert... If your car was getting hot after lots of WOT, then maybe it just doen't have enough cooling capacity, but if it's getting hot in traffic, it's not a lack of capacity...

Do you have other coolers in front of the radiator -- intercooler, oil cooler, a/c etc?

George D

I run two front mounted oil coolers, one is static, and the other is a Derale with an electric fan that comes on at 220 degrees. They make great products, but Ron Davis uses Spal and likely has a setup for my radiator using the factory shroud. The Spal fans are thinner than our 25 year old OE fans, and a mounting bracket would be an easy fab if necessary.

I'll keep you guys posted.

V2Rocket

George, you want to try the Volvo fan? I have a complete spare as pulled off a Volvo.

You'll have to be creative with mounting though.

mahoney944

The factory system cools the car just fine. If you're experiencing higher temps that are above where you're comfortable seeing you likely have a faulty cooling fan relay. I know because i just fixed this issue on my car. Id performed the relay test with the jumper as shown on clarksgarage and it passed but once the car got warm (relay got warm) the fans would act up. If your system checks out and you still have these issues they sell lower temp thermo switch/ thermostat combos that would likely be a cheaper and yet "stock" approach.

George D

No, oil coolers are on each side of the intercooler with good air flow from the vents. The car runs cool at speed, and at idle in traffic in this heat, it's fine. At WOT at speed, the car cools down quickly, but we're moving in these cars quickly keeping your foot down! I don't go to the track in the summer here, way too hot without AC running. My helmet would be soaked. The car currently would be fine, but I'd likely have a heat stroke. Not fun.

This only happened under light throttle, climbing up steep hills behind cars moving 25 to 35 mph in 100+ degree weather. Once it got hot, even with the fans blowing, it stayed that way till I could get some speed. Going down, the temps and gauge stayed at the first white line.

I've spend too much time/money on this car not to spend a little more time/money making it run as cool as possible in all conditions. Scary to think of ruining this motor from not spending under $500 for modern fans.

My wife wants me to get the new M3 TT, but I shared it's only got a 3.0 and doesn't get my respect like my 951 at the wheel. Car's currently running better than ever. Nuts fun, and pulls like a train. The newer TIAL HTA wheel Garrett setup is the best turbo I've ever used on these cars. Linear power delivery. Haven't had a car pull me yet messin around. New fans next, then my tuner, Mario, is programming a meth kit into the TEC for safety, not more power.

George D

Enjoyed reading your post. These modified motors require tenacity towards fitment of all parts not stock. Neat this setup is working well for you.

G

George D

Tom,

I'm using Shark cables, and updated wiring. Fans are spinning as fast as they're capable, just not enough CFM in slow HOT conditions driving below 40mph. Looking at the difference in the fan blades vs newer ones is 25 years of air flow/blade engineering with more efficient motors is worth the change. I'll have excellent working OE fans up for grabs if the local guys don't need them.

Humboldtgrin

I was taught that 100% coolant is accualy the best heat protection. The boiling point is over 400 degree f, but freeze point is 32+ degree f. At 68% coolant 32% water is the best freeze protection but boiling point drops a bit.

PaulD_944S2

Humboldtgrin,

Please explain what you mean by "100% coolant is actually the best heat protection."

Are you saying that pure (100%) ethylene glycol provides best cooling?

mahoney944

He means pure coolant handles higher heat temps better than water/coolant mix does but it freezes above 32 degrees making not ideal for cold weather. By mixing your coolant with water you lose some of its cooling ability being that water's boiling point is lower than coolant but it lowers the freezing point making it ideal for cold and hot weather. I don't think anyone would want to run pure coolant however, its not necessary. And is not how the coolant was designed to work. There is proper mixing %s on the back of the jug for a reason

George D

Please, H20 - water is the best heat transfer and thermal conductivity within a water cooled system like our heat exchanger - radiator - applications, the pumps and other moving parts require lubrication. Glycol increases H20's boiling point, and allows below freezing temps not create an expandable liquid become a larger solid state. Within the realm of automotive radiators transferring heat we have these choices:

•Water
•Deionized Water
•Inhibited Glycol and Water Solutions
•Dielectric Fluids

Running distilled water and a lubricant is what I've used for decades, trust me, my little issues have nothing to do with OE Porsche components as designed or the heat exchange capacity of what liquid used.

Consider what cools a Nuclear Power Generator, then think about a simple radiator transferring heat from air flow.

Tom M'Guinn

You have Shark-style cables running the fans?? That's what I was suggesting as a possibility. If big new cables make the lights brighter, might they make the fans spin faster?

mahoney944

We aren't comparing water vs coolant. We are comparing diluted coolant vs pure coolant in relation to their boiling point. And comparing why one is more or less ideal. I've used a nice 60/40 blend on every vehical I've ever owned and recommend that. Never had issues. You could use pure water if outside temp wasnt an issue, hell you could run pure coca-cola if you like. I'm not agreeing that pure coolant works best I was just clarifing the post as I read it.

Humboldtgrin

This is true for water evaporation. It's 540 calories a gram to take heat away. More then any other cooant avalible. I've read that the little bottle of "Water Wetter" workes well with only distilled water. The system does need a lubricant for the water pump. But the boiling point will be lower if using mostly water in the system. Using a higher PSI radiator cap would help a little bringing up the boiling point more in the coolant system, but risk blowing out hoses and the resivoir.
Also using 100% coolant will not hurt anything! It's a lubricant and a coolant, but I use it as a 60/40 mix as well. Just cost a little more at the part store. And it does have better "HEAT" protection then water due to the boiling point being higher.
However that's at the top of the heat index where we don't want our cars anyways. And water disperses heat better then strait coolant. But if you get your car that hot with just water in it then it might just boil out and leave you without any coolant protection. Bottom line is you should have some sort of coolant if your using water also, to lubricate the water pump and to bring up the boiling point of the water.
As far as you fans go I hope to see what you do. We all love your car!!!!!