https://frsport.com/spal-automotive-...RoC-moQAvD_BwE
The pins.
Mike

 

Thanks -- that is the type of thing I was thinking, but had no idea what it would be called.

I think I'll look around for a fan controller that can do a linear scaled voltage 0-12 output instead of PWM -- that will work with the 4" Spal fans.

 

Well this is interesting. Noctua makes PC fans, CPU headsinks, etc -- they have a line of industrial PWM fans. The "NF-F12 industrialPPC PWM" is a 120mm (4.7") fan rated at 150,000 hours, IP52 water resistant ("Protected from water spray less than 15 degrees from vertical." -- whatever that means), flows 187m^3/h (~110 CFM) and is much thinner than the 4" Spals. They say it will operate at close to 300F also. I wonder if that IP52 water rating is good enough for the job...

They also have a line of IP67 ("Protected from immersion between 15 centimeters and 1 meter in depth.") fans but they are all 24V...

Edit here's an IP67 one @ 105 CFM: https://www.coolerguys.com/collectio...fan-cg12025h12
No word on operational lifetime or temperature rating, though.

 

I use a 24V fan for my Autoexe intake fan. I use a small golf cart step-up transformer that goes from 12V to 24V. $20 on Ebay. Use a IP67 fan, the IP52 will fail rather quickly with water getting in it. The problem with the PWM fans is they don't pull well under stress or higher pressure that is required to pass air through the IC. The Spal's and similar radiator type fans do. The PWM fans are more computer type cooling fans for low pressure pulling or cooling. I did also try to find a fan controller for the Spal with no luck. Even bought the Denali fan controller but it didn't work with the Spal.
Mike

 

Do you mean to say that the PWM and/or computer-type fans have poor static pressure ratings for pulling air through an IC/duct, or that the PWM mechanism interferes with air passing through them as the vehicle speed increases?

 

Poorer static pressure ratings.
Mike

 

I couldn't find any real datasheet for the Spal's. I assume they have better static pressure since they are so thick but who knows what the actual number is. I'd imagine a 120x120x38 or 127x127x38 PWM fan at around 300CFM would be up to the task...

 

Mike's setup is indeed badass. If I were doing another ASP build or OEM++ car that would be my route. I love my big ole M2 intercooler and air box, but they are hard to find complete and I miss my air pump/emissions cuz the car is stanky now. The ease of install, fit, and finish of the u-type and autoexe look to be way better too.

Regarding the duct extension... Take a look at how much difference a duct extension made for my stock IC back in the day: https://www.rx7club.com/3rd-generati...temps-1070765/

 

I recently read that thread and... yeah, WOW.

 

I have the PWM fan controller that Derale makes on my OEM FD fans with my Greddy V-Mount kit and the slow ramping up is nice for idle control and helps keeps voltages up when cruising around slowly as it's not just an on/off switch like the 4 relay system. It actually ends up controlling the temperatures very nicely with minimal adjustment. No more waiting around for higher temperatures to kick the fans on. I'm sure it will wear out the fans quicker, but it's really nice implementing a PWM controller. It also simplifies the wiring which is a bonus.

 

So I was looking through the FSM today trying to figure out what the 2 extra wires on the OEM rad fans were for (FSM schematic in section W says to reference section B-2 for cooling system... I can't find B-2 anywhere in my manual ) but I was wondering if one of them was for PWM signal and one for tach. Is that indeed what's going on?

I'm searching and searching but can't seem to find any automotive-grade 4"-5" PWM fans.

 

So the weird thing about the OEM fans is that they use two positive wires, and two ground wires to use the full potential of the fan. I personally spliced both positives in to one wire and did the same for the grounds. I have no idea exactly how or why it works, but that's just how Mazda did it. If you look through the fan section long enough, you'll be able to find out which wire is which. You should be able to buy any fan and then use a PWM controller to control it theoretically.

 

Your setup is exactly like mine ..... and I use stock IC duct with my Super U .... the difference in output is huge.
Maybe it's the 91 octane you use vs my 93/94?

 

Curious what numbers you’re making.

 

https://www.rx7club.com/time-slips-d...-dyno-1138347/

Check here.

 

Oh, yeah, this is one of my references.

I literally have a link to that thread in a text doc called “350hp.txt”

You bastard.

 

they are two speed fans, with just one wire its low speed, with both its high speed. if you wanted to change that for single speed fans the 2004-2008 Rx8 fan motors fit, and are single speed. the 2009-2011 are back to two speed, with the 99 FD fans (also Tribute diesel)

 

Another fact that is rarely or ever discussed in these discussions about a well designed SMIC system using the U-type SMIC and the Autoexe air box vs. a V-mount is the ability with a setup like mine where the intake air is taken directly from the outside ambient air. All or the vast major of V-mount setups take in their intake air from in the engine bay due to space constraints, which is a disadvantage from the start. If the outside ambient air is let's say 40F, then my preturbo air is likely around 45-50F with my setup(slightly warmed by the piping components). In a typical V-mount with the air intake in the engine bay, that preturbo intake air is at least 90-100F if not greater. That is a 40-50F difference to start no matter what turbo, twin, single, etc. Even on hot days, I still have an advantage but not as great. V-mount are indeed more efficient than my setup after the turbo/turbos, but I have a head start on the starting air temp. Remember also that the turbo that sees cooler air at the inlet is more efficient by as much as 4%, which is also advantageous for my setup. That is why preturbo WMI, which cools the intake air, is often touted for dual spraying WMI systems.
Mike

 

Good info.

I just talked to Sasha at FD Motorsports in Sydney and he says the new U-type IC is about two months out on availability. For reference, here is a prototype image from about two years ago, and a few recent CAD renderings:





What's really interesting to me about this is that the new model comes with a built-in fan (plugs into air pump connector) and the core sits inside one large carbon fiber shell combined with the duct providing thermal insulation from the radiator air.

 

It looks very nice. The built in fan setup should work well as long as the fan itself is skinny enough. It is a very tight fit even with my smaller dual Spals.
Mike

 

Thinking about it, why does the air pump even have a harness connector? It's a mechanical pump... what is the harness connector even for?

 

It's an electromagnetic clutch that is turned on and off by the CPU as needed. You will not be able to simply plug in a fan to it. The wire gauge is too small as it is a low amperage switch, the control is through the CPU or the PowerFC (if used) and it will blow your CPU due to too high a current draw for a radiator type fan. Also, the control itself is for the air pump and the fan would not be on all the time and would come on and off when the CPU calls for the air pump to be on. I don't know why Sasha told you this was the plug you should use. It is not.
Mike

 

Maybe you use the air pump connector to trigger a dedicated fan relay.

 

This would work to trigger a relay for the amperage problem. The main problem is the signal would turned on and off all the time by the CPU. If a PowerFC, it is only on in idle and cruise and off all other times, particularly in acceleration and boost. I am not sure about the stock CPU since I haven't used one in almost 20 years, but I would guess it is similar.
Mike

 

The connector for the air pump gets power from a relay (located near the radiator/airbox/front bumper area). I don't know exactly how much current the relay and wiring is designed to carry, but the wiring diagram shows it's powered by the 15A A/C fuse (which also powers the AC clutch relay). I agree it's not likely to work well for a full-sized radiator fan.