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turbogrill

Block heater core - add pressure sensor?

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Hi,

I don't have a heater in my race car but I do want to monitor the coolant pressure so that a the driver can stop if there is loss of coolant.

I have a N47/F54 combo.

1. Would the heater outlet in the head be a good place to put a pressure sensor (location A) ? Or would it be better to put it in the pump housing (location B)?

 

2. Plugging the heater core have no negative impact on the system? Infact it might have a slight positive impact since there is no reflow back to the pump? 

 

3. If I can remove the thermostat would it be beneficial to remove the bypass altogether? 

 

Car is a ~200hp NA build if it's matter for Endurance racing. 

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I have always used pump outlet/block pressure which should be identical.
The problem using above the head gasket is that the orifices restrict the flow and you don't see the pump cavitating, and in most cases the thermostat is wide open so all you get is cap pressure which can be maintained with quite a bit of coolant loss.

There is a block drain fitting on the left side  at the very back. That is where I put my block pressure line. You will see it flutter and drop when your lower radiator hose collapses from suction out of the radiator, you will see flutter when it cavitates. It will be an interesting learning curve....

Absolutely though, if you cut a hose and start pumping coolant out, you will see that go to nothing fast. Some people put a hobbs switch in that sensing point that triggers below cap pressure (and you bypass it with a rocker swtich during warmup)... It can ground the magneto, kill the ignition, light a big red CHECK WATER light...whatever....

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sorry, missed all of them.

You can plug both the bypasses and plug the heater core fittings as long as you use a thermostat with a couple of big holes in it, a bypass cooler setup, or provide for circulation of the pump while it's warming up. On a race car, a restrictor plate or double 8mm hole in a standard thermostat should provide more than enough flow so the pump doesn't cavitate at startup cold and pump dead headed into the block.

The idea is to give that flow somewhere to go, and in this case, it goes to the radiator so you end up heating up ALL the water in the system, instead of just what is in the block (internal recirculation till thermostat opens) so it takes a bit longer. Just idle it in the pits with the fan off or cover a bunch of the radiator with cardboard to bring it all up to temperature before putting any serious load on it. An easy lap around most tracks gettting the tires up to temperature will accomplish this. I try to keep a thermostat in most things unless it's all balls out racer that sees idle for warmup and 3500+ the rest of the time.

Removing the bypasses and plugging the flow to the heater will insure 100% cooling capacity is available for the engine. It's obligatory on 300 hp, at 200 you can still run a thermostat with the two holes punched in it (or a -6 bleeder line from the lower thermostat housing to the radiator hot tank) to keep the flow and prevent cavitation. 

Bluntly, the heater and bypass represent shunts of the radiator, and decrease total possible heat rejection. The bypasses should be eliminated in all racing cars for maximum cooling. Heater with a core, yes. NEVER loop it, PLUG the holes like when the heater valve is ÖFF"!

Good Luck

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On 11/13/2017 at 7:04 AM, Tony D said:

sorry, missed all of them.

You can plug both the bypasses and plug the heater core fittings as long as you use a thermostat with a couple of big holes in it, a bypass cooler setup, or provide for circulation of the pump while it's warming up. On a race car, a restrictor plate or double 8mm hole in a standard thermostat should provide more than enough flow so the pump doesn't cavitate at startup cold and pump dead headed into the block.

The idea is to give that flow somewhere to go, and in this case, it goes to the radiator so you end up heating up ALL the water in the system, instead of just what is in the block (internal recirculation till thermostat opens) so it takes a bit longer. Just idle it in the pits with the fan off or cover a bunch of the radiator with cardboard to bring it all up to temperature before putting any serious load on it. An easy lap around most tracks gettting the tires up to temperature will accomplish this. I try to keep a thermostat in most things unless it's all balls out racer that sees idle for warmup and 3500+ the rest of the time.

Removing the bypasses and plugging the flow to the heater will insure 100% cooling capacity is available for the engine. It's obligatory on 300 hp, at 200 you can still run a thermostat with the two holes punched in it (or a -6 bleeder line from the lower thermostat housing to the radiator hot tank) to keep the flow and prevent cavitation. 

Bluntly, the heater and bypass represent shunts of the radiator, and decrease total possible heat rejection. The bypasses should be eliminated in all racing cars for maximum cooling. Heater with a core, yes. NEVER loop it, PLUG the holes like when the heater valve is ÖFF"!

Good Luck

 

Thanks I think I got it now!

Whatever I do I will make sure the pump always have somewhere to pump water.

Reason I want to remove most stuff is to remove failure points. No thermostat means no thermostat that can fail, no heater hoses means no heater hose that can fail etc. I haven't raced the 200hp engine yet so I don't know if there is any cooling issues. With our 140hp engine we had ZERO cooling issues in Texas heat enduro racing, we where almost running a little cold we thought. I am mostly worried about pinging, but seems like there are plenty running my setup without issues. (n47 flattop, M445 cam, megasquirt, nice head)

I like your suggestion for pressure sensor location, will check it out. 

 

I might keep the internal bypass, that way I don't have to mess around with the block and screw something up.

 

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