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Coolant/Water Pressure Switch


skierman64
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7 minutes ago, skierman64 said:

I did a bit of searching around and didn't find a exact solution.  Who's running a coolant/water pressure warning light/switch?  What switch are you running?

E30 stock oil pressure switch. 8 psi. Replace often (every two events) as the water will destroy it. 

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Stock E30 oil pressure switch triggers at 8psi.  Works good in non-AIM car.   I did have a switch fail once though, but it was likely the original.  THey are cheap, so buying a new one isnt a big deal.  Grounded a lead to the engine block, which lit up a warning light.  The light does come on when the car is cold, but then goes away when its up to temp.

 

Then switched to something @vtjballeng sold me.  Plugs into AIM.  Was actually a sending unit.  Did not last more than 1 race unfortunately - not sure if it was a fluke or what.

Going to move to a more robust sensor from James soon - Not sure what the specifics on it are - I'm sure he can chime in.

This is a better solution, since the AIM can filter out the warning if the coolant isnt up to temp.  Having the light come on when its not an issue causes driver issues in actually believing the light when it comes on for real.

 

 

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14 minutes ago, skierman64 said:

I did a bit of searching around and didn't find a exact solution.  Who's running a coolant/water pressure warning light/switch?  What switch are you running?

I did something similar to nate on my eclipse, used another stock oil pressure switch (1/8 in. BSP, 2-5 psi) and they fail on my pretty often as well but for a couple bucks a pop I just replace them.

On the altima I have an AIM from Ballenger and I just set up warnings for the CAN bus transmitted coolant temp.

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On 7/24/2019 at 12:16 PM, skierman64 said:

 

Perfect, that's exactly what I'm looking for.  I think it's even the right size for the mount i have in mind.  

 

Have used these before. They live but with hot\cold cycles you can get false positives, depending on your car's operating temp and when you closed the cap. 

 

The temp sender\switches i have found to be a better indicator to the driver about when to shut down. I hook them to a 90db buzzer

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8 minutes ago, Black Magic said:

 

Have used these before. They live but with hot\cold cycles you can get false positives, depending on your car's operating temp and when you closed the cap. 

  

The temp sender\switches i have found to be a better indicator to the driver about when to shut down. I hook them to a 90db buzzer

 

Yep, this works well. 

 

https://90racing.com/products/longacre-water-pressure-sender-52-43241?_pos=1&_sid=87704e037&_ss=r

 

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8 hours ago, tneker said:

Just when I thought we had all the sensors we could ever hope to monitor, this thread pops up..............

 

Don't worry, when neon rads fail they leak slow enough to keep system pressure up, but fast enough to make it 2-4 hours only. 

 

Mine still had good\high system pressure when it was run nearly out of water (to  below the water pump), and the temp went Chernobyl. 

 

I think it is more useful in the circle track world, when after a wreck the driver wants to know if the rad is still attached to the car or if he needs to use the wrecker to get back to pit road.

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On an e30, water pressure switch will give you an indication the accessory belt has come off. Yes it will turn the charge light on as well but at least you can drive around to the pits or even finish a race (minutes left) if it’s just the alternator dead. If water pressure light comes on you’d better find a place to pull off quickly. 

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1 hour ago, Black Magic said:

 

Don't worry, when neon rads fail they leak slow enough to keep system pressure up, but fast enough to make it 2-4 hours only. 

 

Mine still had good\high system pressure when it was run nearly out of water (to  below the water pump), and the temp went Chernobyl. 

 

I think it is more useful in the circle track world, when after a wreck the driver wants to know if the rad is still attached to the car or if he needs to use the wrecker to get back to pit road.

We had a big off at Road America, hit some “jumps”, and the engine moved enough to pull off the lower radiator hose. The pressure warning light came on right away and the driver pulled it back to the pits. 

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At Indy we got tapped in the rear bumper, all was good for 2-3 laps then the upper rad hose disconnected. Luckily the water somehow splashed the windshield and my driver was able to shut down immediately.  

 

We had one previous incident a few years back where I think a pressure switch could have saved a motor. $20 is cheap insurance. 

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On 7/31/2019 at 8:12 AM, Black Magic said:

Don't worry, when neon rads fail they leak slow enough to keep system pressure up, but fast enough to make it 2-4 hours only. 

 

Mine still had good\high system pressure when it was run nearly out of water (to  below the water pump), and the temp went Chernobyl. 

 

I think it is more useful in the circle track world, when after a wreck the driver wants to know if the rad is still attached to the car or if he needs to use the wrecker to get back to pit road.

 

The two times we lost engines during a race, a WP sensor/light likely would have saved both.  First was a thrown belt, the second was a bad/old cap that gave out.  We have always had a temp gauge, but its easy to forget it for a couple laps in the heat of battle. 

 

In addition to the WP and temp lights, I've also capped the vent and installed a barb on the expansion tank to run small hose up to the windshield.

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2 hours ago, Bremsen said:

 

The two times we lost engines during a race, a WP sensor/light likely would have saved both.  First was a thrown belt, the second was a bad/old cap that gave out.  We have always had a temp gauge, but its easy to forget it for a couple laps in the heat of battle. 

 

In addition to the WP and temp lights, I've also capped the vent and installed a barb on the expansion tank to run small hose up to the windshield.

 

I have once had a driver use the gauge to stop...it was me....I think gauges are wishful thinking. 

 

I am not sure stopping the water pump (thrown belt) would reduce the water pressure by a measurable amount, the pump doesn't make much of a pressure drop across it. Based on temp, the system would still be well above the few psi cutoff of the switch. You can always wire both a pressure and temp switch in parallel, so either being tripped pulls your warning system to ground. 

 

We have had 100% success in the 90 db siren stopping the driver before warping the head. 

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20 hours ago, mcoppola said:

@Black Magic I like the buzzer idea.

Have to start looking for one (or 2) of those.

 

Look for it as a boat (marine) part.....they use em for the same driver awareness (lack there of) that we have in race cars. 

 

This one is weaker, at "only" 80db....which is as loud as some engines when sitting in the car. I doubt you could miss it for long.....

 

https://www.amazon.com/Piezoelectric-Signal-Flashing-Warning-Dashboard/dp/B00UW6HSFM

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20 hours ago, Squelch said:

I use a 0-15 psi sensor that feeds the DAQ system.   Very nice to be able to track coolant pressure.

If water temp is over 180 and pressure drops below 3 PSI it triggers a warning on the dash.

 

 

With software you can determine if your pressure temp profile curve has been changed, which would give you a long warning of water loss. Beyond us hobbyists, but at top pro level that is how you can tell if you have a small leak (temp for x pressure rise changes).

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On initial start up and warm up pressure moves around a bit, then once the thermostat opens and the temps stabilize, the pressure gets quite stable.

When you pop a water pump/alternator belt, the pressure rises, quite quickly, the "three lights of death" (Charge, brake, engine) come on and a moment later the high pressure (9 psi) warning comes on.

 

On our 2002 Ford Focus we have a simple hobbs switch (As "Hotrod" mentioned) no DAQ.  At Indy our driver was reporting temps each lap on Sunday..  temps were consistent, then one lap, they reported a lower temp.. 5 degrees lower, didn't seem like much and a few moments later the low coolant pressure light came on...  few moments later loss of power.   Driver shut it down.

 

In the end it was a split radiator hose.

 

The hind sight is that the drop in temp was probably due to a loss of pressure and the temp sensor was reading steam, once all vented, the pressure drop triggered the hobbs switch.. and the warning came on.    

 

 

I feel a coolant pressure indicator is a valuable item to have.

 

 

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46 minutes ago, Squelch said:

On initial start up and warm up pressure moves around a bit, then once the thermostat opens and the temps stabilize, the pressure gets quite stable.

When you pop a water pump/alternator belt, the pressure rises, quite quickly, the "three lights of death" (Charge, brake, engine) come on and a moment later the high pressure (9 psi) warning comes on.

 

On our 2002 Ford Focus we have a simple hobbs switch (As "Hotrod" mentioned) no DAQ.  At Indy our driver was reporting temps each lap on Sunday..  temps were consistent, then one lap, they reported a lower temp.. 5 degrees lower, didn't seem like much and a few moments later the low coolant pressure light came on...  few moments later loss of power.   Driver shut it down.

 

In the end it was a split radiator hose.

 

The hind sight is that the drop in temp was probably due to a loss of pressure and the temp sensor was reading steam, once all vented, the pressure drop triggered the hobbs switch.. and the warning came on.    

 

 

I feel a coolant pressure indicator is a valuable item to have.

 

 

 

Yep, we once lost a lower radiator hose and it just dumped underneath and the driver was none the wiser.  He continued lapping until the engine let go. Total loss. We watched the video and the temp gauge never climbed, in fact it dropped a little. 

 

We soon put a simple longacre 3psi warning light on, but struggled with false positives for whatever reason. Moved the switch around the system, tried another switch, still false positives.  Ended up just covering it with electrical tape and I’ve since moved on from that team/car.  Maybe it was something odd about that old Datsun, I don’t know... I’ve got a kit ready to put on my current car... need to bump it up the priority list. 

 

The short of it, a pressure warning light is a GREAT thing, but it’s imperative to eliminate all false positives so the driver will not hesitate to shut down.

 

 

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