Time Delay Relay - Anyone use them?

wesinls

wesinls

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Trying to think about all the wiring I'll be doing on the car - and unlike the Holley system I have now, the trigger for the fans will come from two different sources (or so I think) - one from the factory Honda ECU from what I've been told is 205, and for the 2nd fan I plan to put one of those thermal ground switches on a radiator bung at say 180.

Issue is when you turn on ignition and go to start and having the fans running, not ideal...Some people have their fans on a switch - which scares me (if you forget and not paying attention).

I am thinking of using one of these time delay relays - say 10 seconds...given the car time to start, settle down a bit, and then fan(s) kick on....it looks like this relay can do both delays - i.e, have fans stay on for x amount of time once ignition is off, or delay x amount of time on after ignition.



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Used plenty, not that particular one though.

Delay on or off are different models. One doesn't appear to do both.

If you wire it the way you noted in your first sentence, you would need to put this on both circuits, OE and 180.
 
Kraut_n_Rice said:
Used plenty, not that particular one though.

Delay on or off are different models. One doesn't appear to do both.

If you wire it the way you noted in your first sentence, you would need to put this on both circuits, OE and 180.
Click to expand...
Yes - noticed after my posts its two different relays - and both part numbers on that screenshot.
 
I have both fans come on at 180, very little surge on the engine. Get the 180 degree sensor for the Honda.

When I ran the 205 sensor, the engine would not start cooling until 212 or so, then it would cool down to 205 and fans would turn off. With a turbo, you are putting out a lot of heat. I changed radiator, fans, water wetter and so forth and it ran way too hot. One fan will not cool the engine back to 180 when hot when you are trying to cool the turbo down, at least that is my experience, keep it simple.

When running hard, I am running at 205 and upwards to 210 even with 180 sensor
 
Mishimoto makes a replacement fan switch that turns on at a lower temperature than OEM. I do like the idea of having one fan turn on at a lower temp though.
 
I have a fan switch that turns on the fans at 50% at a set temp and then Slowly increases fan speed as temp increases
I really like how much less fan noise is created with 2 fans at 50% it is way less noise than one at 100%
 
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Arch Stanton said:
I have a fan switch that turns on the fans at 50% at a set temp and then Slowly increases fan speed as temp increases
I really like how much less fan noise is created with 2 fans at 50% it is way less noise than one at 100%
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This sounds great! Can you point to where I can get that type of switch?

On mine.. I currently have the fans on a manual switch because I like to have more control of when they come on. I have a Honda V6 and as mentioned, the ECU triggers the fans to come on at 205 degrees. That's a bit late for my taste; that's why I have the manual switch. But as a safe guard, I wired the ECU 205 degree trigger wire to a red idiot light on the dash. If that light comes on, I know the temp has hit 205 and I forgot to flip the manual fan switch.
 
I’ll look at the car tomorrow it’s been on the car about 10 years also a v6 turbo 3.5 Honda
I just looked up digital fan control on summit racing site it looks like at least 3 companies make them
 
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Brushless fans are the latest rage.
Weld a bung in the radiator and they adjust speed to maintain temp.
No switch from anywhere, computer, manual etc.
 
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I have this switch from Pegasus racing and its been great. On at 190 and off around 170. During duning it keeps the car around 195 the whole time. No manual switch to think about. Granted I have a custom water outlet but could not be hard to add to the OEM honda setup.

Setrab Thermal Fan Switch only, 190 F, 1/8 NPT - Pegasus Auto Racing Supplies

This compact 2-terminal (non-grounding) switch from Setrab turns on at 190F and off at 170F. Perfect for controlling a cooling fan relay. 1/8 NPT male threads.
www.pegasusautoracing.com www.pegasusautoracing.com
 
MPC said:
This sounds great! Can you point to where I can get that type of switch?

On mine.. I currently have the fans on a manual switch because I like to have more control of when they come on. I have a Honda V6 and as mentioned, the ECU triggers the fans to come on at 205 degrees. That's a bit late for my taste; that's why I have the manual switch. But as a safe guard, I wired the ECU 205 degree trigger wire to a red idiot light on the dash. If that light comes on, I know the temp has hit 205 and I forgot to flip the manual fan switch.
Click to expand...
I was running manual switches for the same reason, then I change the temp sensor to the 180 degrees, all works perfect now. Haven't used the manual switches for 2 years.
 
On one of the last street cars I built, I had a tube made, with a bung in it, that I inserted in the lower radiator hose.

The bung held the temp switch, that turned the fans on, or off.

Why do it that way?

The coolant exit temp from the radiator, is actually what the fans are controling. So isn't that Where you want the fan temp sensor to be?

Everyone knows what a hot soak is, right? When you turn the key off, the engine temp goes WAY up, because coolant circulation just stopped!

A factory engine ECU, knows these things, and adjusts injector pulse width, and spark timing, accordingly.

Should your cooling system be controlled like that? It's not really necessary.

Having the temp sensor in the lower radiator hose, let's the fans do what they Should do, control the actually coolant temperature.

I could sit there and watch the fans cycle on at off at idle, like it was a computer controlled late model car, but this was a 71 (built to fuck) Buick Skylark.

And the fans were never on at start up. Even after a hot soak situation.

👍🏼
 
if you are rewiring the car......just put a PDM in and be done with it. your fan control strategy is just one reason why.

first of all, no 70's technology cheesy external relays or fusing needed. then the control parameters you are looking for can be easily implemented, fans will not run if the engine isn't running, turn fans off based on vehicle speed and ambient temps, stage multiple fans to come on at whatever temps you desire and so forth. Never mind the wiring architecture is MUCH simpler with a PDM making for way less wiring needed to do what you want to do.
 
If 60 amps of additional load is creating a starting issue than maybe your battery is undersized and more CCAs are called for.
 
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