My Reroute drawing
#44
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It's not half and half, though, since the hose to the heater core is smaller than the hose to the radiator, and if you restrict the flow to the heater core you can improve on that. It's more like 3/4 cold water, 1/4 lukewarm water (the heater still removes heat).
You can either get laid when the car warms up, or you can get laid while the car is warming up. Return the heater core to the radiator and you'll be so cold in the mornings you won't be able to physically get it up.
You can either get laid when the car warms up, or you can get laid while the car is warming up. Return the heater core to the radiator and you'll be so cold in the mornings you won't be able to physically get it up.
Also, I recommend you get a port for an aftermarket water temp sensor for future use, because after you see my Omori water gauge incorporated into my instrument cluster, you're going to wish you weren't such a homo because then you'd have a chance to see a naked woman for the first time in your pathetic life.
#47
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I wouldn't either. But I also didn't know Begi would sell just that part machined for a t-stat and tapped the way I want it for $20.
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#48
For most, this is fine. Most people that overheat aren't getting enough air through their heat exchangers. It's not that 10%-15% that's killing them.
And I'd love to know why every vendor on earth is afraid to put a solid reroute on the market.
#49
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I want: T-stat + bsp gauge + stock temp sender + GM water temp sensor with plugs for the bsp and GM until I'm ready to use them. yay.
#53
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And that's really the #1 problem with the cooling system. The water pump is in the front of the engine. The thermostat outlet is in the front of the engine. Therefore, when the thermostat opens, a great deal of water goes from the pump, up the front of the engine, and then directly out. The consequence of this is that the volume of water circulating through the back of the engine is greatly diminished relative to the front of the engine after it warms up and the thermostat opens.
The principle objective of a good coolant re-route therefore is to relocate the thermostat and outlet to the back of the head, such that the volume of water flowing through the back of the engine does not decrease when the thermostat opens. Doing this modification alone brings the Miata cooling system roughly up to par with the original 323 design, and solves probably 95% of the problem.
This business concerning the routing of the water coming out of the heater core is entirely secondary, and of far less importance than the issue of thermostat location. After the thermostat has been relocated, then one can consider modifications to the heater core path, such as adding a restriction or returning heater water to the radiator inlet rather than the mixing manifold. These modifications will improve the overall efficiency of the system somewhat, but are totally unrelated to the primary issue of uneven front-back coolant distribution.
This is where Hyper really went wrong, incidentally. He got too hung up on these secondary concerns, and never saw the primary issue.
#54
Aside from speculation based on observation, do we have any empirical data to show that there is more circulation between the water pump and the radiator then through the rest of the engine?
Basically what I am saying is, what if there is a restriction built into the path between the pump and the front neck to prevent over circulation of water?
I understand the re-route solves over heating issues on track cars, even though I only heard of maybe 3 such incidents on this forum. However, could it be possible that factory design of the coolant system was intended to maintain proper operating temps. While the re-route on average drops those temps?
In my mind, and I could be wrong, a properly functioning engine cooling system is the one that keeps the engine at the optimal operating temp in all driving conditions basically removing the possibility of large temperature swings.
I equate this too CPU cooling, the best heatsinks arent the one that keeps the processor the coolest, its the one that keeps the processor at its proper temperature under every load condition.
I understand the 323gtx was done differently, and it was the homologation of rally car. I can understand mimicking the reroute for race use, but wouldnt it hurt(and i use that lightly) the engine, if its driven in any other conditions with sub optimal operating temperatures.
Basically what I am saying is, what if there is a restriction built into the path between the pump and the front neck to prevent over circulation of water?
I understand the re-route solves over heating issues on track cars, even though I only heard of maybe 3 such incidents on this forum. However, could it be possible that factory design of the coolant system was intended to maintain proper operating temps. While the re-route on average drops those temps?
In my mind, and I could be wrong, a properly functioning engine cooling system is the one that keeps the engine at the optimal operating temp in all driving conditions basically removing the possibility of large temperature swings.
I equate this too CPU cooling, the best heatsinks arent the one that keeps the processor the coolest, its the one that keeps the processor at its proper temperature under every load condition.
I understand the 323gtx was done differently, and it was the homologation of rally car. I can understand mimicking the reroute for race use, but wouldnt it hurt(and i use that lightly) the engine, if its driven in any other conditions with sub optimal operating temperatures.
#56
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Sam,
The point of moving the thermostat to the rear, and thus mimicking the original 323 design, is NOT that it causes the engine to run cooler in general. The primary goal is to cause the entire engine to run at a more uniform temperature. In the Miata design, the back of the engine has been documented to run considerably warmer than the front. Here is one page which has some good data on it: http://users.telenet.be/miata/englis...nt_reroute.htm
A secondary effect of relocating the thermostat to the rear is that the overall cooling capacity of the system is increased. This does not mean that average operating temperatures will necessarily decrease- the thermostat is still doing its job of regulating temperature and only permitting water to enter the radiator when necessary. However because the total volume of coolant passing all the way through the engine is increased significantly, the likelihood of overheating is lessened in an engine that's being pushed hard. IOW, we make the cooling system able to dissipate more heat, though it is still able to regulate the engine temperature properly.
A caveat- note how I stated earlier that this business with the heater core was secondary? If you do relocate the heater core return to the upper radiator hose, then you have essentially bypassed the thermostat and will experience over-cooling. This is true regardless of whether the thermostat is relocated to the back or left in the front. These two things (relocating the thermostat vs. changing the heater core return) are entirely separate issues and must not be confused with one another.
And there already is a restriction in the path between the water pump outlet and the water neck outlet- it's called the thermostat. But the fact that any water at all is being permitted to exit the front of the engine means that more water is passing by the #1 cylinder than the #4, and thus #4 will always run hotter than #1.
To continue your CPU analogy, relocating the thermostat to the back accomplishes essentially what you describe- it keeps the whole engine at a more uniform temperature under all operating conditions.
The rear-mounting of the thermostat is not a race-only thing, incidentally. It's how nearly ALL inline engines work, be they made by Mazda, Toyota, Chevy, Hyundai, Lada, Fiat, Caterpillar, Suzuki, etc. The Miata is the oddball, and it is the way it is because the engineers cheaped out when repackaging the engine for a RWD layout.
The point of moving the thermostat to the rear, and thus mimicking the original 323 design, is NOT that it causes the engine to run cooler in general. The primary goal is to cause the entire engine to run at a more uniform temperature. In the Miata design, the back of the engine has been documented to run considerably warmer than the front. Here is one page which has some good data on it: http://users.telenet.be/miata/englis...nt_reroute.htm
A secondary effect of relocating the thermostat to the rear is that the overall cooling capacity of the system is increased. This does not mean that average operating temperatures will necessarily decrease- the thermostat is still doing its job of regulating temperature and only permitting water to enter the radiator when necessary. However because the total volume of coolant passing all the way through the engine is increased significantly, the likelihood of overheating is lessened in an engine that's being pushed hard. IOW, we make the cooling system able to dissipate more heat, though it is still able to regulate the engine temperature properly.
A caveat- note how I stated earlier that this business with the heater core was secondary? If you do relocate the heater core return to the upper radiator hose, then you have essentially bypassed the thermostat and will experience over-cooling. This is true regardless of whether the thermostat is relocated to the back or left in the front. These two things (relocating the thermostat vs. changing the heater core return) are entirely separate issues and must not be confused with one another.
And there already is a restriction in the path between the water pump outlet and the water neck outlet- it's called the thermostat. But the fact that any water at all is being permitted to exit the front of the engine means that more water is passing by the #1 cylinder than the #4, and thus #4 will always run hotter than #1.
To continue your CPU analogy, relocating the thermostat to the back accomplishes essentially what you describe- it keeps the whole engine at a more uniform temperature under all operating conditions.
The rear-mounting of the thermostat is not a race-only thing, incidentally. It's how nearly ALL inline engines work, be they made by Mazda, Toyota, Chevy, Hyundai, Lada, Fiat, Caterpillar, Suzuki, etc. The Miata is the oddball, and it is the way it is because the engineers cheaped out when repackaging the engine for a RWD layout.
Last edited by Joe Perez; 02-25-2009 at 04:57 PM. Reason: Spelling
#59
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To summarize, the modified diagram that Brainey posted in message #31 of this thread is, in my opinion, the most optimum configuration for a street-driven car, and the one which is most similar to a "normal" inline-4 engine.
The overall maximum cooling capability could be increased slightly by adding a restrictive orifice between the pre-thermostat outlet on the back and the heater core inlet (to further bias coolant flow towards the radiator and away from the mixing manifold when the thermostat is open) and this is how I plan to do mine when ETD starts shipping their reroute kit. Doing this will not have any negative impact on warmup time or temperature stability (unlike returning the heater core to the upper radiator hose) although it will decrease coolant flow slightly while the thermostat is closed, and will increase the likelihood of pump cavitatation. I tend not to run high RPMs while cold however, so this is not a major concern.
The overall maximum cooling capability could be increased slightly by adding a restrictive orifice between the pre-thermostat outlet on the back and the heater core inlet (to further bias coolant flow towards the radiator and away from the mixing manifold when the thermostat is open) and this is how I plan to do mine when ETD starts shipping their reroute kit. Doing this will not have any negative impact on warmup time or temperature stability (unlike returning the heater core to the upper radiator hose) although it will decrease coolant flow slightly while the thermostat is closed, and will increase the likelihood of pump cavitatation. I tend not to run high RPMs while cold however, so this is not a major concern.