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EP3 wiring the A/C fan & radiator fan together ?

T

TAOTAO

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Hi All,

I have EP3 CTR, that it long term project to track car. I bought 2 slim fan to help my with the PWJDM battery relocation (I know it not needed but I already got it).

as the car going to get rid of the AC etc in the future, I want to wire both fan to the same connection (rad original connection), I got the OEM connector also.

somebody did it and know if the relay will handle it ? the relay that I have is "omron made in usa" - G8HN-UA-007607

I try to search on the web but cant find this specific model specs.

the fan are 80W 12V fans so it approx 7+- ampere each.
 
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Don't know about the relay, my guess would be yes though. Try it, see if it gets hot or not.

If the aircon is going, why not just remove the fan? If you want your aircon to be functional, you don't want it to be wired to the radiator fan switch anyway. I'd remove fan and pulley and run the non aircon aux belt until I was ready to remove the A/C unit.

edit:... or wait, are you asking if you can run two slimline radiator fans from the A/C relay?
 
You don't want a cabin fan at all? What about windscreen clearing when cold/humid? Even on the track that's a possible issue I'd have thought?
 
I think he wants to know if he can run the AC fan as a second radiator fan. I'm guessing you could be our non AC track car has been fine with temps so far.
 
Ah, forgot about the A/C radiator having its own fan :picardfp:

However, is it necessary? If you have a decent Alu radiator then it should cope just fine with the one fan, and if you don't then you should be able to hook whatever triggers the A/C fan relay up to the same source.

The fan has a 15A fuse attached, I'd be loathe to run so close to that, a decent current spike there (when first starting the fans turning, for example) could be enough to blow the fuse.
 
I already have full size alu radiator but the ambient temp here on the track are very hot (35-40C +), as for that I want to go on the safe side and have 2 fans.

If the fan have just 15A so it will be too close to it limit.

somebody know if there is a way to connect the A/C fan relay to behave same as the rad ?

thanks.
 
It's unlikely, the sensors usually feed back to the ECU and then the ECU sends a signal back out to the relay to activate the fan, so you'd have to trick the ECU in some fashion. The safest way to do it, electrically speaking (I've never fvcked around with civic wiring), would be to buy another relay and run an inline fuse in the correct place. Then connect the input of your new relay to the input on the OEM rad fan one. That, or get a bigger relay and run both from the one. The ECU fan signal should have enough power to run two relays.

I'm not sure how much you know about electronic component specs, but they're given on something called a data sheet, so usually if you type in '### datasheet' it comes up on google. This is the one you're looking for... https://www.omron.com/ecb/products/pdf/en-g8hn.pdf . So, unfortunately the number you've given there is a serial number for that particular relay not the full model number. But that's fine - if the one you've got is the standard, it won't be able to handle two fans on continuous load. If it's the high power one, it might, but you'd be pushing very close to the limits.

You also might be able to pinch the A/C relay and then you just need an inline fuse connector and some correctly rated wires.



Edit: If your ambient temps are 35-40 Degrees C I would consider running the 2nd fan on a dash switch so you have total control. That way you have a back up if the engine starts running too hot, like using the 2nd fan in emergencies rather than as a part of the stock set-up. That way, when it's too hot you don't have a serious problem and have an extra kick of cooling to keep you going.

Edit 2: Actually, going back to your original question I guess if you do some clever wiring and the A/C delete before hand you could just use the A/C switch to do as I've said above. Which I wonder if that is your original question? To just use the cabin air dial to run a rad fan?
 
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I already run in this PDF, but as I mention, there isn't any specs for this specific model.

I will try to figure out what is the best way to wire the second fan to operate in parallel with the rad fan.

If anybody have experience, fill free to replay.

Thanks.
 
EP3 wiring the A/C fan & radiator fan together ?

That is the correct data sheet, it gives you the specs for all models of G8HN relays. It's possible Honda got some specially made for them, or the manufacturers have changed their part numbers since. Whichever one comes on the car is largely irrelevant for what you want to know though.

Even if you have the highest rated 12V DC one (unlikely) it doesn't have a big enough safety factor to comfortably constantly run two fans from it.


Sent from my iPhone using Tapatalk
 
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