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Going to single OEM fan question...

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Old 01-21-2018, 08:04 PM
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Default Going to single OEM fan question...

Searched this extensively and couldn't find anything in detail. Just that the second fan is used for cars with AC and it comes on at a higher temp (unless modified).

Just upgraded to a Supermiata radiator and Qmax reroute. Beautiful parts!

The car has no AC and I want to go to a single OEM fan. To remove the AC fan (passenger side) can I just cut the wires, cap them off (epoxy heat shrink) and tuck them back in the harness? Or is it more involved than that?

Engine is a '99 1.8 with a Hydra EMS if that matters.

Thanks for any help!
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Old 01-21-2018, 09:24 PM
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Just unplug the fan and leave the wire there. Dont cut that **** you goof.
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Old 01-21-2018, 09:31 PM
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Originally Posted by Leafy
Just unplug the fan and leave the wire there. Dont cut that **** you goof.
Damn, didn't realize how long the cable is for the ac fan. Need to pull apart my harness and find the plug.

Thanks!


Last edited by LukeG; 01-21-2018 at 09:45 PM.
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Old 01-21-2018, 11:13 PM
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I personally needed 2 fans when temps got above 95* outside on my street car with no AC. That was before ducting, so take that with a grain of salt.
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Old 01-21-2018, 11:54 PM
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I doubt that one OEM fan is going to cut it given that BOTH OEM fans should activate when the coolant exceeds a certain threshold, regardless of whether or not the A/C is ON (that's how my MSM fans worked before switching to the TSE radiator and single MASSIVE SPAL fan).

I certainly wouldn't be tracking the car with a single OEM fan, you'll blow your radiator cap as soon as you pull into the pits because there's no way that single OEM fan will suck enough air through your radiator to help shed heat from your coolant.

Also, you're in Texas - it gets F'N hot there!
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Old 01-22-2018, 02:07 AM
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I've always had a single OEM fan (car never had a/c) and I haven't had any issues with the car overheating in the pits even on 35C+ (95F) days.
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Old 01-22-2018, 03:20 AM
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Thanks guys! Got the idea for this from from Emilio's cooling system thread... https://www.miataturbo.net/race-prep...-thread-79930/

"Fans and shrouds
On a track car, only one fan is needed and no extra shrouds. We use one OEM fan and call it a day. Any extra shrouding actually inhibits high air flow mass at higher speeds on cars with adequate ducting. There is a sort of minimum air flow mass required to cool a high hp track car. Add full coverage shrouds for low speed, light load street cooling problems and you are handicapping high speed, high load airflow. On cars that are more street oriented, have A/C and big power, fans can help bandaid airflow enough to keep it alive if it never goes on track. If that same car that requires massive dual fans to survive on the street ever gets driven in anger on the track.. it’s a better idea to ditch the shrouds, start cutting up the hood and improve ducting through the nose. You will rarely see fans and full coverage shrouds on a purpose built racecar unless it's an offroad car where low speeds and debris are concern for an externally mounted core."

I'm going to give it a shot and keep an eye on the coolant temp.
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Old 01-22-2018, 12:31 PM
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Originally Posted by Lokiel
I doubt that one OEM fan is going to cut it given that BOTH OEM fans should activate when the coolant exceeds a certain threshold, regardless of whether or not the A/C is ON (that's how my MSM fans worked before switching to the TSE radiator and single MASSIVE SPAL fan).

I certainly wouldn't be tracking the car with a single OEM fan, you'll blow your radiator cap as soon as you pull into the pits because there's no way that single OEM fan will suck enough air through your radiator to help shed heat from your coolant.

Also, you're in Texas - it gets F'N hot there!
Just to clarify: cars without OEM A/C came from the factory with only one fan. I can't say whether or not that's the way to go in high-power builds with high ambient temps, but it definitely works on my car in stock configuration.
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Old 01-23-2018, 06:29 PM
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Default Amps of fans

Originally Posted by LukeG
Searched this extensively and couldn't find anything in detail. Just that the second fan is used for cars with AC and it comes on at a higher temp (unless modified).

Just upgraded to a Supermiata radiator and Qmax reroute. Beautiful parts!

The car has no AC and I want to go to a single OEM fan. To remove the AC fan (passenger side) can I just cut the wires, cap them off (epoxy heat shrink) and tuck them back in the harness? Or is it more involved than that?

Engine is a '99 1.8 with a Hydra EMS if that matters.

Thanks for any help!
I purchased my 2002 and the guy before me went to O'Rielys and got the biggest fans that would fit in the space and installed them. The car continued to have a overheating problem. I chased it down.... fans were not coming on due to the load that the wire guage was rated to carry had been exceeded by the fans. It toasted the connections and all the way back to the main fuse block. I had to rewire the car. I did keep the fans and bumped the wire up to handle the amps. Good Luck.
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