Carpokes Porsche Forum

Hello,

I live in Southern AZ and cooling is a hot topic for me. A proper working cooling system is pretty good at keeping temps in check but I still run hot if I'm stuck in traffic mid day in ambient temps over 100. This is with AC going full blast and it starts to warm up if I'm in traffic.

I was looking for improvements in both cooling and AC performance at low speed and in traffic. The best way I know to improve both is with more airflow. As an aside, I keep the belly pan and front end air guides in place as those parts are important to prevent hot air reversion (pulling hot air back through the cooling stack after it already went through the condenser and radiator).

A shop local to me builds brushless fans for specialized applications. They are small but have worked with top race teams (until the products were banned because of their performance advantage). I dropped off a 3 blade early fan and a 6 blade late fan on the shroud to see what they can come up with. https://www.steeleracingproducts.com/

Below is the outcome. They fit the brushless motor to the OE blades and it is wired as a soft start 100% on.


-----------------------------OEM 3 Blade-----SRP 3 Blade----OEM 6 Blade--------SRP 6 Blade
Startup Amp Spike----46.5A-----------------0A---------------------57A------------------0A
Current Draw------------11A-------------------15A------------------14.1A---------------18.5A
CFM--------------------------1020 CFM----------1199 CFM---------1277 CFM--------1555 CFM

So a 20% increase in flow with stock, bolt in fit.

I plan to wire these to maintain OE control. to do this I'm using an off the shelf Faston (1/4"spade terminal) housing that will accept the stock chassis side harness. (just de-pin and re-pin to the new housing)
Bypass the ballast resistor and leave the passenger side resistor disconnected.

The operation will be one fan comes on 100% at the first temp setting. This is because the PWM is tied to the power lead. Then once the temp hits the high temp switch on the OE relay the other fan comes on. The goal here is a simple install using OE controls.

For full PWM control an aftermarket ECU or dedicated fan controller can be used but that is another $200 or so.

I will install these soon and give it a go. I like the fit and operation of the OE style paddle blade fans as well as the shroud. That design maximizes fan area and thus airflow. For comparison, the CSF setup uses tiny 9" brushed spal fans that pull a combined 1180cfm. That is less than one OE 6 blade fan.

Great work, I've been running 1 fan on at a time from my PDM, but it seems to run hotter for some reason. Your better fans may negate this issue with more flow but I've gone back to 2 on at 50%DC @92degc and stepping up to 100%DC @ 102degc or A/C on.

Does your PDM have a PWM control? If so the brushless fans have a PWM input, for now it is spliced to the + lead so when power is applied it runs to 100% but a simple 3rd wire input can allow fan speed control from an outside controller.

Right now I just have pwm on the outputs because I'm running the OEM brushed fans, I wsh I'd looked into it and put the wiring for a pwm output to a fan controller into my extra body harness but I hadnt thought about fans when I built it.

Like you say theres not many aftermarket fans out there that actually flow better than the stock fans as well

I also wanted stock fit and these ticked that box.

Very nice. Does the extra flow come from higher RPM's? Or?? I have a brother-in-law in Phoenix, and can't imagine the car-heat challenges with ~110 temps for days on end... Parallel flow condenser and bigger aluminum radiator would seem almost a must? When I was in Miami, I put in a brand new factory radiator and it dropped the temps by over a needle's width. There was nothing 'wrong' with the original, but I could tell from the head gasket that the original owner filled his radiator with a garden hose, so the calcium and minerals reduced the radiator's ability to cool. I also ran about 15/85 antifreeze to water -- just enough to lubricate -- and that helped quite a bit too.

Tom, Yes, higher RPM form the higher torque motors. I have a parallel flow condenser and I have run some of the aftermarket all aluminum rads but the one I ran didn't perform as well as an OE rad. I also run a mostly water (deionized) mix for coolant as there is no need for the anti freeze element. On the highway it cools well as there is plenty of airflow and also airflow extraction from the bottom of the car. Like I mentioned, city driving and stop and go is what is killer.

There are corrosion inhibitors you want in the anti-freeze. Run 50/50 for maximum engine life.

For the SRP parts, is this something they'll offer to folks, if you get hold of them? I took a look at the website but didn't find anything that indicated they offer just the motors, which is what I think is happening with your setup, correct?

This is very cool (pun not originally intended).

Cheers

Zirconocene wrote: Wed Jul 09, 2025 8:14 am For the SRP parts, is this something they'll offer to folks, if you get hold of them? I took a look at the website but didn't find anything that indicated they offer just the motors, which is what I think is happening with your setup, correct?

This is very cool (pun not originally intended).

Cheers

They did the conversion for me as I just dropped off the OE setup and the installed the new motors. For the conversion they press on an adapter to the motor that fits the OE blades. They are happy to do the conversion.

Cheers,
Sean