Engine Bay Cooling Options

Yes, the D-C uses the electronic controller to vary pump flow to accomplish the temperature regulating task.

My point is that on a single action stat system, the stat is an open/close valve. On a double action stat system, the stat acts as both an open/close valve and a diverter valve. In an exxie with no stat in place to act as a diverter, coolant flow will be split between going forward to the rad and recircing back into the engine. Ultimately a large % of coolant will never make it forward to the rad to get cooled off.

Hi Dan,

the thermostat works as per the diagram below. I'm planning to install a Davies Craig EWP (80) and have already modified a spare thermostat housing to suit. Essentially I removed the thermostat and blocked off the opening between the two compartments (indicated by the red line in the diagram) which should result in the same operation as when the thermostat is fully open.

Cheers,
Dom.

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Hey all,

So during the 3600 mile of the Four Bangors Lemons Rally we noticed that running the car for almost 16 hours a day means a large amount of heat in the engine bay. We used the blower motor on a manual switch quite a bit but we found that it just got too hot for what we liked back there (even if the engine head temp was manageable). We left the hatch open while driving sometimes to let heat come out, but I think we need a more permanent solution.

I'm open to some pretty ridiculous things, Ive thought about putting fans on top of the engine cover either sucking air up (since it seems like that's the way the air flows while moving) or blowing down. Other options would be things like greatly increasing the airflow of the rear blower by replacing it or something along those lines.

What do you guys think? I've seen the air scoops over the top of the car and thought about that but it wont help with the sitting in traffic heat (Toronto was hard on the car).

eA1tPlc.jpg


Thanks!

I wouldn't be too concerned about the ambient temperatures in the engine compartment unless you are experiencing vapour lock or hot starting issues. If you are experiencing cooling issues in traffic, in my experience, it is related to the fact that the water pump doesn't circulate sufficient coolant when idling. The easy solution is to manually activate the radiator fan and bring the idle speed up to 1200 - 1500 RPM. A far better solution (as others have alluded to) is an electric water pump. This will allow the circulation of sufficient coolant irrespective of engine RPM and, as a bonus, allow for the circulation of coolant after the engine has shut down. This will be far more effective than trying to reduce the temperatures externally.

Cheers,
Dom.
 
I have been saying for years that the water pump at idle pushes very little water. I hooked up the heater to the Fatrat using heater hose along the outside of the shifter tunnel. I fired up the car to test for leaks and make sure I was getting flow and the two hoses never even got warm (easy to put my hands on the hoses) even after the temp gauge indicated the motor had heated up. After I revved up the motor a bit I found the hoses starting to warm up and only after driving the car did I get them too hot to touch. Surely many of you have sat at a light in cold weather and noticed the heater blowing cold or tepid air.

I can see venting the engine bay to provide cooler intake air but I would think different routing of intake air would be simpler solution or the rain tray deleted just above the air filter if using sport filter.
 
Regarding the bypass thermostat design on the X and a electric water pump. I could possibly see a few options; as Karl said make a new T-stat housing that eliminates the bypass, as Dom said modify the stock housing to make it function as Karl described, or maybe(?) this...
Could the stock T-stat housing and thermostat be retained to function normally while using a electric pump? I realize the electric pumps are intended to control flow by changing the speed of the pump. But it seems they could be used as a direct replacement (so to speak) for the stock water pump - leaving its speed constant - and let the regular T-stat control temp. The benefit of increased flow over the stock pump would still be in effect.
 
Regarding upgraded pumps (electric or otherwise). Depending on how severely the stock pump is under rated for the X's needs (i.e. reduced circulation at idle), maintaining a colder coolant temperature (i.e. better heat exchange at the radiator) MAY compensate for the reduced circulation at idle to some extent. Notice I said "depending on how severe" and I emphasized the word "may". My thought is a colder temp of coolant could still keep the engine at the desired running temp when the pump's circulation isn't quite ideal due to having a greater temperature differential between the coolant and the engine. Therefore allowing for enough heat removal to make up for the lower circulation rate. This would also depend on the T-stat's rating, as discussed in my previous post.

However I agree, IF the water pump is not providing enough circulation, then the best solution would be to increase the pump's performance. I'll refer to another thread that discussed the different stock designs of pumps for the A/C and non-A/C versions of X. Although it was not able to be confirmed, there was some speculation that the A/C style pump MAY have a slightly greater flow at lower speeds. IF that is true, then it may be sufficient to eliminate the idle speed temperature issue. Yes, lots of "if's" and "may's", it needs to be experimented with to determine the answer.

Another possible solution for decreased circulation rate is to increase the pump's rotation speed. This was also discussed previously. Too much increase may lead to cavitation, but a mild increase in rotation could possibly provide enough increased circulation at idle without any cavitation effects at upper RPM's (street use, not track). Increasing the pump's rotation speed is easy with pumps that have the "bolt on" type of pulleys. Those pumps are available for the non-A/C housings as well as the A/C ones (look for a water pump designed for engines with smog pumps). The pulley diameter can be changed to alter the pump's rotation speed. I found there are a few different stock pulley sizes for the bolt on style pumps. On one of my X's I swapped the pulleys to increase the water pump speed by a calculated 10 to 15%. Hopefully that will be enough to aid the idle circulation, yet won't be so much as to create issues at higher RPM's.
 
Regarding the engine bay temperature. There will be some benefit to reducing the ambient air temp around the engine - aside from induction intake air temps. Remember that there are three types of heat exchange. Reducing the temp of the air surrounding the engine will reduce the engine's temp by means of external engine heat exchange. Naturally it will not be nearly as efficient as the water cooling system within the engine, but it will help. This also applies to all structures within the engine bay; alternator, starter, electronics, fuel system, etc....cooler temps will help things to work better and live longer in a otherwise overheated environment.
 
Currently replacing my exhaust header and down pipe. New one comes out the bottom of the engine bay instead of passing through the firewall under the rear truck. That leaves a 4 x4 hole that serves no purpose. Seems like a good place to add a 4 or 5 inch puller on a manual switch.
 
Regarding an electric water pump, I can confirm that a Davies Craig pump works fine with the standard thermostat in place to control the temp, that's what I have on my track X with the pump running at full flow constantly. Saves buying the electronic controller, just make sure the thermostat is operating properly. Modifying the thermostat as Dominic shows and using the electronic controller is the alternative.
 
Regarding an electric water pump, I can confirm that a Davies Craig pump works fine with the standard thermostat in place to control the temp, that's what I have on my track X with the pump running at full flow constantly. Saves buying the electronic controller, just make sure the thermostat is operating properly. Modifying the thermostat as Dominic shows and using the electronic controller is the alternative.

Which example of the DC pump do you have? They have a variety of units of different capacities. Thanks
 
My unpopular opinion is that these are not air cooled engines as was noted and that engine bay thermal management via air circulation is likely to be a small effect at best. Every time this topic comes up, I read a lot of opinions but not many measured values. I measured the temperatures and the only time I see any values higher than water/thermostat temperature is after shut down. Which is why Fiat installed a blower fan that activates at ~160F at the base of the carb/FI intake. End of rant!
 
Regarding an electric water pump, I can confirm that a Davies Craig pump works fine with the standard thermostat in place to control the temp, that's what I have on my track X with the pump running at full flow constantly. Saves buying the electronic controller, just make sure the thermostat is operating properly. Modifying the thermostat as Dominic shows and using the electronic controller is the alternative.

I did not realize that there are D-C pump options that do not rely on their controller to work properly. Will have to take another look! ;)
 
Although I have seen DC's product demonstrations at shows like SEMA, and reviewed their literature, I have not done a lot of detailed research on them so I cannot say for sure. But I assume with a electric pump (any electric driven device for that matter), you could wire it directly without a controller and it will simply function at 100% all the time. Then the stock T-stat assembly will control flow (and therefore engine temp) from there. Especially with the X's bypass design the coolant flow will never be zero so the pump would not be fighting complete resistance at any time. Might be different with other vehicles that do not have a bypass T-stat. Any reduction in flow that might occur (perhaps when the T-stat is closed and flow is directly through the bypass) would create some added workload on the electric motor. But I don't think it should cause any real problems, especially since the pump has bearings and is cooled by the water flow. Therefore I would say that any of their pumps could be used this way. The best thing would be to contact DC, but I think they will say you must buy all of their added components regardless. The fact that GregS has been successfully doing it this way should be a good indicator that it will work.
 
A friend of mine built a D-sports racer back in the 60's and has been racing it ever since (more recently in vintage racing). He has a 128 engine (sleeved down to get the desired displacement) mid mounted and the cooling system consists of a front mounted radiator (no fan) and a little pair of boat bilge pumps to circulate the coolant (no engine mounted water pump). Not a lot of flow but at track speeds it has enough heat exchange to maintain the engine temp. Naturally I would not suggest it for anything we are discussing. However they are wired directly to run all the time with the stock T-stat setup to control warm up (using a cooler temp stat). I think if those tiny inexpensive electric pumps do not burn up (he's had the same ones on it for ages), then there isn't a lot of flow resistance in the SOHC's bypass system.
 
Which example of the DC pump do you have? They have a variety of units of different capacities. Thanks
The pump I have is EWP80. I removed the original pump and made a new pipe to run below the headers from a plate fixed where the pump was. Needed to get a shorter alternator belt.
You could leave the old pump housing in place with a blanking plate where the front part was, and use a short belt. Or you could leave the pump intact with just the impeller removed, retain the pulley and original belt. Or even leave the complete old pump, and use the electric pump to boost the original.
Davies Craig offer 3 options with their pumps, 1. Use the digital controller, 2. Use a thermal on/off switch, 3. Continuous running.
 
The pump I have is EWP80. I removed the original pump and made a new pipe to run below the headers from a plate fixed where the pump was. Needed to get a shorter alternator belt.
You could leave the old pump housing in place with a blanking plate where the front part was, and use a short belt. Or you could leave the pump intact with just the impeller removed, retain the pulley and original belt. Or even leave the complete old pump, and use the electric pump to boost the original.
Davies Craig offer 3 options with their pumps, 1. Use the digital controller, 2. Use a thermal on/off switch, 3. Continuous running.

Many thanks.
 
My unpopular opinion is that these are not air cooled engines as was noted and that engine bay thermal management via air circulation is likely to be a small effect at best. Every time this topic comes up, I read a lot of opinions but not many measured values. I measured the temperatures and the only time I see any values higher than water/thermostat temperature is after shut down. Which is why Fiat installed a blower fan that activates at ~160F at the base of the carb/FI intake. End of rant!

The main issue that i have with the blower setup is that it will never activate when the engine is running on my 87. The ground that is switched to turn on the blower motor is the same ground from the oil pressure sensor. Only way it turns on when the engine is running is by manual switch, and that also turns my oil light on :)
 
I'm of the opinion (and it is only that - my opinion) that the ambient air temp inside the engine bay of any vehicle should be considerably LOWER that the internal engine temp - at any time (during or after running). As a rough example, lets say your T-stat is around 180* (assuming that is the actual engine temp), the surrounding air should be well below around 150* maximum at any time. In other words, there will always be more heat inside an engine than outside of it. If not there is a real problem with your setup. That may be why Fiat set the blower fan at 160*. To me, ideally it would be even a greater difference than that, ambient engine bay temps below a max of 120* (or less depending on the atmospheric air temp). To clarify an earlier statement I made, this is not so much to cool the engine (which it will do to a minor degree), but more so to help prolong the life of everything else that lives within and around the engine bay. And the air to the induction intake should be SIGNIFICANTLY lower than all of that, closer to outside ambient air temp (say 70*). Yes, engines are slightly more efficient at higher operating temps - within reason. But I'll take reliability and longevity over a marginal improvement in emissions or fuel consumption any day (especially for a play car like these).

Many front engine vehicles have a temp control unit for the electric radiator fans that allow them to run-on after engine shut down. This is primarily to keep the engine bay temps from soaring and causing heat soak. Something like that could be added to the engine bay of the X. Either to the existing blower, or even better to an auxiliary electric fan, controlled by a temp sensor and timer switch to allow the fan to come on at any time, during or after engine running, and maintain the bay's ambient temp under the set level. If you've added a oil cooler (which EVERY X should have), then the auxiliary electric fan could also act as the cooling fan for the oil cooler. Which brings up a seldom mentioned topic on Xweb - oil coolers (but I'll save that for a future thread).
 
Without real time testing of engine bay temps, it's all supposition although I don't disagree with your analysis. It shouldn't be hard to find a remote sensor thermometer to stick in various places in the engine bay to test temps. With sport filters on carbed Xs, intake air is in the hottest part of the engine bay, right up against the underside of the engine cover and directly above the exhaust manifold. I found it alluring that the DCOEs I ran on the rat had the intake located in the trunk where the intake air should have been much cooler. No temp testing and no dyno readouts so who knows.
 
Update, i removed the rain tray. Temps in the back went down (as perceived by feeling the intake after driving 30 miles, hardly scientific i know). But running the blower fan indicates using the oil light if the injectors are over 160 degrees and that never turned on when checking, so it definitely is helping cool the outer block and accessories.

Things took a turn for the worse there, when trying to bleed the radiator i carefully snugged the bleeder and it wouldent seal, reseated it a couple times and no good. Found that the threads in the radiator are a bit stripped. Decided "screw it" im gonna throw a 1/8th inch schrader air valve on it and see if the thread is close. The thing fit perfectly and sealed up!

The valve might fail, its not meant for that. But for now bleeding the radiator is as easy as letting air out of any tire :D

Then my brake master cylinder failed spectacularly but that's besides the point of this thread. I think this car wants me dead for not letting it die.
 
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