Bell's New Coolant Reroute: a Review
05-30-2009, 09:23 AM
#42
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The thermostat must go in the back of the head because it needs to pressurize the coolant. The flow of coolant dictates where the thermostat is placed. Since the flow of cooled coolant enters the engine from the lower radiator hose at the lower housing and exits out the back of the head it needs the thermostat at the point of exit for flow control and proper pressurization to avoid hot spots in the head and block.
If the thermostat is kept in the front of the engine, the rear part of the head/block would tend to run hotter from the lack of flow.
If I get a chance, I will post my reverse-flow/electric pump setup.
If the thermostat is kept in the front of the engine, the rear part of the head/block would tend to run hotter from the lack of flow.
If I get a chance, I will post my reverse-flow/electric pump setup.
Sav's reason of standing water would make sense but I'd have a heater feed to circulate coolant around. Also like Marc said, there should be flow through the t-stat at all times, even when fully closed.
Please show your set up, sounds bad ***.
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05-30-2009, 12:21 PM
#44
Joe and Steph, you both have plenty of room between the up-pipe to the intake mani and the inlet to the radiator. With my BEGI S4 kit and the Godspeed rad the two pipes nearly touch. The rad inlet hose is deformed against the up-pipe.
Shorten the elbow to the intake mani on the up-pipe to open up some space? No way the radiator inlet hose can turn left and around as it is.
Shorten the elbow to the intake mani on the up-pipe to open up some space? No way the radiator inlet hose can turn left and around as it is.
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05-30-2009, 01:05 PM
#45
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@ cueball: The pictures on Bell's webpage (which, granted, depict the old-style routing like I have) suggest an under-the-throttle routing:
I wonder if some variant of this could be made to work with your steroid-infused radiator?
@ everyone: I just noticed (while looking for that picture) that there's a stern warning on the webpage:
Ha! Ain't that the truth. 
In all seriousness though, most of the major issues I encountered were ones I created for myself, like buggering up that stud trying to remove it the wrong way, and doing a ****-poor job of driving in the freeze plug the first time (which itself was a deviation from Bell's design.) If you take it slow, think about what you're doing, and discipline yourself to put down the tools and walk away for a bit if you get frustrated, then it's actually not all that bad of a job.
I wonder if some variant of this could be made to work with your steroid-infused radiator?
@ everyone: I just noticed (while looking for that picture) that there's a stern warning on the webpage:
Originally Posted by Bell's Website
** 2nd Note: This part can be installed without pulling the motor. However, expect a few bloody knuckles and a few curses. And don't say we did not warn you. **
In all seriousness though, most of the major issues I encountered were ones I created for myself, like buggering up that stud trying to remove it the wrong way, and doing a ****-poor job of driving in the freeze plug the first time (which itself was a deviation from Bell's design.) If you take it slow, think about what you're doing, and discipline yourself to put down the tools and walk away for a bit if you get frustrated, then it's actually not all that bad of a job.
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05-30-2009, 03:14 PM
#47
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That quote applies to just about any automotive modification covered on mt.n, or in general. I have to remind myself of that from time to time. Plus it is nice to have a garage and a second car. I can walk away whenever I want, close the garage door, and take the other car to work. There were times in my broke-college-student past when that was not true.
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05-30-2009, 03:43 PM
#48
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Also, bear in mind that your routing is incompatible with 1.8 NAs (as well as NBs which are using an MS1) as they have a CAS poking out the back of the exhaust cam, and probably incompatible with anybody pre-'01 who is using the factory ignition coils as well. Not that anybody who is serious about boost should be using those coils anyway. :rolleyes"
That is correct. The "Racer" kit does nothing more than return the heater core water to the upper radiator hose rather than the mixing manifold. It's available as an add-on option to the "Turbo" reroute, but I don't advise it, as doing this defeats the operation of the thermostat by running water through the radiator all the time.
I spent some time on the phone talking with Steph and Corky and convinced them to flip the names. This one that I have was originally labeled the "Racer" reroute, and the other one the "Turbo" reroute. That made no sense to me, as this one is ideal for street cars, whereas the other is pretty much a track-only affair.
In the stock 1.6 setup, there is a water outlet on the bottom of the intake manifold. This connects to the outboard port on the bottom of the throttle body. Then the inboard port on the bottom of the TB connects to the thermostatic air valve on the upper portion of the intake manifold, and the other port on the TAV connects to the bottom of the thermostat housing. Finally, a second hose on the bottom of the thermostat housing connects to the nipple on the mixing manifold. (the reason it passes under the thermostat is to ensure that water is circulating down there so that the thermostat opens when it should).
In my setup, I'd originally placed the oil cooler between the outlet on the intake manifold and the inlet on the throttle body. So I simply removed the line leading from the oil cooler to the throttle body, and the one from the TAV to the mixing manifold, and ran a new hose from the oil cooler outlet to the mixing manifold.
If you don't have an OEM 1.8 coil cooler on your 1.6, you'd simply run a hose from the outlet of the thermostatic air valve on the top of the intake manifold down to the nipple on the mixing manifold, as I've illustrated here:
If you do not have an oil cooler, and you also wish to eliminate the factory interheater (the coolant running through the TB and TAV), then you can just block off the coolant outlet on the bottom of the intake manifold and the coolant inlet at the mixing manifold, and run no hoses at all. With the thermostat removed from the front, it's no longer crucial to have coolant circulation through that circuit.
Of course, if you use the blockoff plate supplied by Bell, rather than removing the lower thermostat housing from the head, you can leave the stock hoses alone and they'll work just fine.
That is correct. The "Racer" kit does nothing more than return the heater core water to the upper radiator hose rather than the mixing manifold. It's available as an add-on option to the "Turbo" reroute, but I don't advise it, as doing this defeats the operation of the thermostat by running water through the radiator all the time.
I spent some time on the phone talking with Steph and Corky and convinced them to flip the names. This one that I have was originally labeled the "Racer" reroute, and the other one the "Turbo" reroute. That made no sense to me, as this one is ideal for street cars, whereas the other is pretty much a track-only affair.
In the stock 1.6 setup, there is a water outlet on the bottom of the intake manifold. This connects to the outboard port on the bottom of the throttle body. Then the inboard port on the bottom of the TB connects to the thermostatic air valve on the upper portion of the intake manifold, and the other port on the TAV connects to the bottom of the thermostat housing. Finally, a second hose on the bottom of the thermostat housing connects to the nipple on the mixing manifold. (the reason it passes under the thermostat is to ensure that water is circulating down there so that the thermostat opens when it should).
In my setup, I'd originally placed the oil cooler between the outlet on the intake manifold and the inlet on the throttle body. So I simply removed the line leading from the oil cooler to the throttle body, and the one from the TAV to the mixing manifold, and ran a new hose from the oil cooler outlet to the mixing manifold.
If you don't have an OEM 1.8 coil cooler on your 1.6, you'd simply run a hose from the outlet of the thermostatic air valve on the top of the intake manifold down to the nipple on the mixing manifold, as I've illustrated here:
If you do not have an oil cooler, and you also wish to eliminate the factory interheater (the coolant running through the TB and TAV), then you can just block off the coolant outlet on the bottom of the intake manifold and the coolant inlet at the mixing manifold, and run no hoses at all. With the thermostat removed from the front, it's no longer crucial to have coolant circulation through that circuit.
Of course, if you use the blockoff plate supplied by Bell, rather than removing the lower thermostat housing from the head, you can leave the stock hoses alone and they'll work just fine.
Alright, lets see if I have this figured out. If I put a cap on the lower thermostat housing barb, along with a cap on the intake manifold barb, I can eliminate the coolant going through the throttle body? I've already eliminated the thingy right above the injectors by looping a small piece of line between the two barbs, as you can see here:
After all this, if I "T" the heater core outlet (the one closest to the master cylinder) into the upper radiator hose, I'll have a rerouted coolant system, good for the track? It all seems too simple, too cheap, and too good to be true. Apologies for the slight thread-jack.
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05-30-2009, 10:35 PM
#49
I'll likely cut the rad inlet shorter as well as the intake up-pipe. Not sure about having straight slips there without the rolled edges. Guess I'll have to use he-man strength on the clamps. (yes I'm nervous about that too)
I removed the bolt and nut off the rear housing. There is a hard line running almost up against that housing right across the middle of it. In my dark *** garage I have no idea what it is. I'm working pretty much by feel. Fuel? ABS? Can't get the housing off the stud with that line in the way. It sure doesn't have much give. Ideas? Thought I'd ask before I just bend the crap out of it.
I removed the bolt and nut off the rear housing. There is a hard line running almost up against that housing right across the middle of it. In my dark *** garage I have no idea what it is. I'm working pretty much by feel. Fuel? ABS? Can't get the housing off the stud with that line in the way. It sure doesn't have much give. Ideas? Thought I'd ask before I just bend the crap out of it.
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05-30-2009, 11:40 PM
#51
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Originally Posted by curly
After all this, if I "T" the heater core outlet (the one closest to the master cylinder) into the upper radiator hose, I'll have a rerouted coolant system, good for the track? It all seems too simple, too cheap, and too good to be true.
The treatment of the heater core's output is a secondary issue. The treatment of the lines going to the throttle body and intake manifold are entirely peripheral and pretty much totally unrelated to the reroute idea. In my case, I was bored, and since I live in southwest Florida where the ambient temperature rarely falls below the melting point of gallium, I decided "frak it."
The principal problem with the stock routing is that with the thermostat in front, much of the coolant coming in from the pump goes straight up and out without having ever circulated through the back of the engine. As a result, the engine is undercooled and unevenly cooled. By blocking the front outlet and relocating the thermostat and radiator feed to the back of the head, we force nearly all of the coolant coming from the water pump to flow all the way through the entire engine.
Now, if you were to take the outlet of the heater core and run it to the upper radiator hose, you would increase the cooling capacity of the engine. Unfortunately, you'd also cause it to take half of eternity to warm up, as you've now got 100% of the coolant going through the radiator all the time, whether the thermostat is open or closed. If you are able to idle the car for 10 or 20 minutes after startup without moving it (so that no airflow passes through the radiator) then it will eventually come up to temp. But this isn't really a feasible thing for most of us.
Now, if you already did the rear-thermostat relocation, that's about the only issue. If you didn't however, then once the temperature does rise enough to open the thermostat, you'll be back to the situation where a lot of the coolant is once again bypassing the back of the engine and just going straight out the front, and the back half of your engine is now being undercooled again.
Nice shock mounts, BTW.
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05-31-2009, 01:16 AM
#52
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The principal problem with the stock routing is that with the thermostat in front, much of the coolant coming in from the pump goes straight up and out without having ever circulated through the back of the engine. As a result, the engine is undercooled and unevenly cooled. By blocking the front outlet and relocating the thermostat and radiator feed to the back of the head, we force nearly all of the coolant coming from the water pump to flow all the way through the entire engine.
If you were to take the outlet of the heater core and run it to the upper radiator hose, you would increase the cooling capacity of the engine. Unfortunately, you'd also cause it to take half of eternity to warm up, as you've now got 100% of the coolant going through the radiator all the time, whether the thermostat is open or closed. If you are able to idle the car for 10 or 20 minutes after startup without moving it (so that no airflow passes through the radiator) then it will eventually come up to temp. But this isn't really a feasible thing for most of us.
Now, if you already did the rear-thermostat relocation, that's about the only issue. If you didn't however, then once the temperature does rise enough to open the thermostat, you'll be back to the situation where a lot of the coolant is once again bypassing the back of the engine and just going straight out the front, and the back half of your engine is now being undercooled again.
Now, if you already did the rear-thermostat relocation, that's about the only issue. If you didn't however, then once the temperature does rise enough to open the thermostat, you'll be back to the situation where a lot of the coolant is once again bypassing the back of the engine and just going straight out the front, and the back half of your engine is now being undercooled again.
Mine? They're just the NB hats that I got with my Fat Cat bump stops. Didn't know they were anything special, but thanks anyways!
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05-31-2009, 11:22 AM
#53
Jesus. I've been trying the M-tuned egr line adjustment method, whacking the crap out of it with a block of wood and a hammer, and it's still not out of the way. That's one tuff pipe. I'm afraid of damaging the end connections to keep whacking on it like this. WTF to do next?
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06-01-2009, 03:50 AM
#54
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oooooh, I like the "higher routing" of the one stephani(e) had on her thumbs. It would allow me to still do oil filter changes from the top of the engine bay...instead of from the side/below.
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06-01-2009, 08:56 AM
#55
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At the same time, there is sufficient documentation to show that in the stock configuration a significant temperature gradiant exists across the engine from front to back, and that a rear-thermostat reroute corrects this condition and improves overall cooling system efficiency.
Originally Posted by curly
They're just the NB hats that I got with my Fat Cat bump stops. Didn't know they were anything special, but thanks anyways!
Jesus. I've been trying the M-tuned egr line adjustment method, whacking the crap out of it with a block of wood and a hammer, and it's still not out of the way. That's one tuff pipe. I'm afraid of damaging the end connections to keep whacking on it like this. WTF to do next?
Y'know, I just realized something. Now that the charcoal canister has been evicted from my engine bay, I think I may have space to put the oil filter up there. Does anybody remember the name / web address of the fellow who builds the plate to sit it behind the headlight on an NB? (edit: NVM, it's Thompson. And they appear to be sold out with no estimated date for more...)
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06-01-2009, 11:48 PM
#56
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Jesus. I've been trying the M-tuned egr line adjustment method, whacking the crap out of it with a block of wood and a hammer, and it's still not out of the way. That's one tuff pipe. I'm afraid of damaging the end connections to keep whacking on it like this. WTF to do next?
I wish I had known sooner to warn you. I will add it to the website though for future users. I blocked mine off and expected an engine code. Not so far though. I am quite surprised. The solenoid was left intact, just had the manifold welded closed and the plate put on the intake manifold.
Stephanie
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06-02-2009, 12:04 AM
#57
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Do you sell a block off plate that weighs as much if not more than the moon? Cueball would like that.
Steph, I bought one of your old reroute kits from a member on the board. It has a welded tube off the spacer and no groove for the thermostat. The groove isn't a problem, I can machine it at work, but do you have diameter and depth so I can program it? I'm guessing the welded tube goes to the heater core, and you later replaced with the threaded hose barb shown in Joe's pictures above, is this correct? And there doesn't seem to be threads for the coolant sensor, would you mind providing those thread specs to this lazy bum?
And last question, and anyone could probably answer this, but why can't we use the stock miata water neck behind the head? Does the outlet point in the wrong direction? The fan switch is ground off and just acting as a plug right now, I figure if I don't have enough clearance, I could grind the whole thing down further and weld it shut (again at work, haha). But if it points in the wrong direction, it won't really matter either way.
Steph, I bought one of your old reroute kits from a member on the board. It has a welded tube off the spacer and no groove for the thermostat. The groove isn't a problem, I can machine it at work, but do you have diameter and depth so I can program it? I'm guessing the welded tube goes to the heater core, and you later replaced with the threaded hose barb shown in Joe's pictures above, is this correct? And there doesn't seem to be threads for the coolant sensor, would you mind providing those thread specs to this lazy bum?
And last question, and anyone could probably answer this, but why can't we use the stock miata water neck behind the head? Does the outlet point in the wrong direction? The fan switch is ground off and just acting as a plug right now, I figure if I don't have enough clearance, I could grind the whole thing down further and weld it shut (again at work, haha). But if it points in the wrong direction, it won't really matter either way.
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06-02-2009, 09:19 AM
#58
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And last question, and anyone could probably answer this, but why can't we use the stock miata water neck behind the head?
The ones from the later 1.8 engines will fit, but they wind up pointing diagonally upwards, rather than sideways. Here's a picture, from fun02se's reroute:
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