What do you think of this coolant reroute idea?
#42
Don't forget about coolant flow to the turbo...nobody has talked about that here...
I have coolant coming out from the back of the head, after the t-stat (I've used the original OEM t-stat cap), using a J-shaped hose and going to the turbo. From the turbo, the coolant return goes back into the mixing manifold just before the water pump.
The rest of my reroute follows bbundy's: hole drilled in intake manifold, with fitting underneath -- goes to the heater core inlet. From the heater core, coolant goes to t-junction and returns to mixing manifold/water pump.
I have coolant coming out from the back of the head, after the t-stat (I've used the original OEM t-stat cap), using a J-shaped hose and going to the turbo. From the turbo, the coolant return goes back into the mixing manifold just before the water pump.
The rest of my reroute follows bbundy's: hole drilled in intake manifold, with fitting underneath -- goes to the heater core inlet. From the heater core, coolant goes to t-junction and returns to mixing manifold/water pump.
#43
Hey Jason, what do you think of these guys? They are saying that you can't do the reroute without a spacer. I am doubtful of their claims. Who is right?
http://forum.miata.net/vb/showthread.php?t=244148
http://forum.miata.net/vb/showthread.php?t=244148
#44
If the t-stat is closed and there is 0 flow past it, the coolant can flow out the front of the head, assuming you have the heater pickup point there.
If you're concerned about getting a bit of warmed coolant past the t-stat so it sees the coolant temp, there is a small, 3/8" pickup point in my head - I can't remember if factory used it, but I use it for the factory oil warmer, TB, and turbo.
If you're concerned about getting a bit of warmed coolant past the t-stat so it sees the coolant temp, there is a small, 3/8" pickup point in my head - I can't remember if factory used it, but I use it for the factory oil warmer, TB, and turbo.
#45
Yes, according to my engine, the 3/8" line pumps coolant through the intake manifold and then back to the water pump. You can see it join with the line just beneath the stock thermostat position.
I figure I can safely just run the 3/8" line straight from the intake back to the pump inlet and block off the connection with the thermostat stalk (presumably there for circulation past the otherwise isolated thermostat). This will actually ensure some amount of flow out the back of the head when the thermostat is closed. It is right next to the new thermostat location too.
One stupid question though, what do I do about the temperature sensor fitting that runs into the stock heater hose housing? I assume the TEC3 doesn't care, or it supplied it's own sensor for water temp that you have mounted elsewhere. I suppose I can run a wire to the front of the engine, though that will artificially reduce my coolant temp readings. Or if I can get the probe loose, I can just tee it in somewhere in the back of the head. I'm mostly curious what you did.
I figure I can safely just run the 3/8" line straight from the intake back to the pump inlet and block off the connection with the thermostat stalk (presumably there for circulation past the otherwise isolated thermostat). This will actually ensure some amount of flow out the back of the head when the thermostat is closed. It is right next to the new thermostat location too.
One stupid question though, what do I do about the temperature sensor fitting that runs into the stock heater hose housing? I assume the TEC3 doesn't care, or it supplied it's own sensor for water temp that you have mounted elsewhere. I suppose I can run a wire to the front of the engine, though that will artificially reduce my coolant temp readings. Or if I can get the probe loose, I can just tee it in somewhere in the back of the head. I'm mostly curious what you did.
#46
I've done a reroute based on BBundy's diagrams and have put my CLT sensor (TEC3 setup) in-line using a T-fitting, just before the heater core inlet. That way, even when the t-stat is closed and coolant is still flowing to the heater core (fitting between #3 and #4 runner of ITM) and turbo (small fitting off back of head, on passenger's side of t-stat flange), you get a reading that (IMHO) is closest to actual coolant going through the block/head. I have the OEM temp sensor in a T-fitting from BEGi, and the fan temp sensor on the rear t-stat flange.
#48
Hey that kludgy job looks familiar!
I didn't use a spacer. The coolant source for the heater is from a hole I drilled and tapped in the head. This way I didn't need a spacer, I could keep the EGR tube, and didn't need to get it from all the way in front of the head.
see:
IIRC the temp sensor is screwed into an existing hole that has a plug from the factory. My memory could be wrong...
BTW because the heater supply is now a 1/2" hose instead of 5/8", heater is noticeably not as hot in the winter. Not really a problem in CA....
I didn't use a spacer. The coolant source for the heater is from a hole I drilled and tapped in the head. This way I didn't need a spacer, I could keep the EGR tube, and didn't need to get it from all the way in front of the head.
see:
IIRC the temp sensor is screwed into an existing hole that has a plug from the factory. My memory could be wrong...
BTW because the heater supply is now a 1/2" hose instead of 5/8", heater is noticeably not as hot in the winter. Not really a problem in CA....
#54
But below 80C, how much cooling do the rear cylinders need? There is still that 3/8ths hose going out of the back of the head next to the thermostat housing.
I could put a 3/8ths inch or 1/2 inch restrictor in the heater hose so that the pump would draw more water out of the back of the head before the thermostat opens. If that fails, I can always order up a spacer and do the reroute that way.
I could put a 3/8ths inch or 1/2 inch restrictor in the heater hose so that the pump would draw more water out of the back of the head before the thermostat opens. If that fails, I can always order up a spacer and do the reroute that way.
#55
But below 80C, how much cooling do the rear cylinders need? There is still that 3/8ths hose going out of the back of the head next to the thermostat housing.
I could put a 3/8ths inch or 1/2 inch restrictor in the heater hose so that the pump would draw more water out of the back of the head before the thermostat opens. If that fails, I can always order up a spacer and do the reroute that way.
I could put a 3/8ths inch or 1/2 inch restrictor in the heater hose so that the pump would draw more water out of the back of the head before the thermostat opens. If that fails, I can always order up a spacer and do the reroute that way.
Rather than doing that, I would say you would be better off not using the 3/8 line in the back, but drilling a 3/16 to 1/4" hole in the t/stat flange to allow initial back-of-the-head flow and the t/stat to see the temp rise.
#56
I'm currently in the process of a coolant re-route. There's a guy here who makes an aluminium pipe to go from the rear of the clock back to the top hose.
So I've swapped the thermostat housing and thermostat from the front of the block to the back, retaining the entire front 'stalk'. I've made a blanking plate for the front from 5mm aluminium plate, and have drilled and tapped for the water temp sensor to go in the blanking plate.
I use the exhaust side water line on the bottom of the front housing to feed coolant to the turbo - basically plumbing the turbo inline on that hose. The plumbing to the intake plenum is unchanged.
On the back of the block (in the rear thermostat housing) there is a 3/8"? outlet that sits before the relocated thermostat. A mate of mine fabricated up a brass inline hose join to step up from the small hose to the larger hose that enters the heater - that way the flow to the heater is essentially the same, and maintains flow while the thermostat is closed before it heats up.
I'll know if it's working once the replacement motor goes back in as of this weekend, as a result of a bent conrod a couple of weeks back.....
So I've swapped the thermostat housing and thermostat from the front of the block to the back, retaining the entire front 'stalk'. I've made a blanking plate for the front from 5mm aluminium plate, and have drilled and tapped for the water temp sensor to go in the blanking plate.
I use the exhaust side water line on the bottom of the front housing to feed coolant to the turbo - basically plumbing the turbo inline on that hose. The plumbing to the intake plenum is unchanged.
On the back of the block (in the rear thermostat housing) there is a 3/8"? outlet that sits before the relocated thermostat. A mate of mine fabricated up a brass inline hose join to step up from the small hose to the larger hose that enters the heater - that way the flow to the heater is essentially the same, and maintains flow while the thermostat is closed before it heats up.
I'll know if it's working once the replacement motor goes back in as of this weekend, as a result of a bent conrod a couple of weeks back.....
#57
I added two pics to my vb garage to show how I changed the coolant reroute thermostat to clean it up a little. It is the neck of a 1.8 thermostat cut off and sanded to fit inside the hose with the fan switch mounted in the original 1.6 thermostat cover.
The back of the motor has another 1.6 thermostat cover that I had a welder friend modify to give me the threaded hole for the temp sensor and the nipple for the heater line.
The thermostat has two 1/8" holes drilled into the flange so that the hot water flows to the thermostat so that it can see the temperature rise and open at the right time.
I have done the same without the heater core in the circuit to a friends 1.8, but drilled a larger hole in the thermostat flange for circulation before the thermostat opens.
The back of the motor has another 1.6 thermostat cover that I had a welder friend modify to give me the threaded hole for the temp sensor and the nipple for the heater line.
The thermostat has two 1/8" holes drilled into the flange so that the hot water flows to the thermostat so that it can see the temperature rise and open at the right time.
I have done the same without the heater core in the circuit to a friends 1.8, but drilled a larger hole in the thermostat flange for circulation before the thermostat opens.
#58
No, the 3/8th hose out the back of the head is going the stock route. When it gets to the front of the engine bay, instead of joining with the old thermostat location and then going to the pump inlet, it goes straight into the pump inlet from the intake manifold. The picture is above. That is the only mod I made.
#60
No, the 3/8th hose out the back of the head is going the stock route. When it gets to the front of the engine bay, instead of joining with the old thermostat location and then going to the pump inlet, it goes straight into the pump inlet from the intake manifold. The picture is above. That is the only mod I made.
back of head - oil warmer - TB - turbo - water pump inlet
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