Engine Bay Cooling Options

Conda

Conda

Daily Driver
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).

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Thanks!
 
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Carl discussed removing the rain tray in the engine cover and using a canvas waterproof temporary removable cover when stored or it's raining. The engine cover will than let the heat escape like a chimney.
 
Yea, removing the rain tray really opens up engine bay cover...but can make a mess of the engine bay. I'm not convinced engine bay "cooling" is needed with a water cooled motor. I saw no significant difference with and without the rain tray installed in regard to engine temps but then never put my car through extreme use like you do. How about a remote temp sensor placed on the underside of the engine cover to monitor what's really going on in the engine bay?
 
carl said:
Yea, removing the rain tray really opens up engine bay cover...but can make a mess of the engine bay. I'm not convinced engine bay "cooling" is needed with a water cooled motor. I saw no significant difference with and without the rain tray installed in regard to engine temps but then never put my car through extreme use like you do. How about a remote temp sensor placed on the underside of the engine cover to monitor what's really going on in the engine bay?
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You must be a nut or something, wanting to measure values before making a change based on questionable logic.




(By the way that was humorous sarcasm...…:p )
 
As a highly qualified nut, my suggestions are to hack up the engine bay, rear trunk, bulkhead, side scoops, engine lid, and rear tail light panel. Then add large side scoops, a open type engine lid, a rear panel grill, and a large electric fan to move air from the engine bay, through the now open rear trunk, out the back end of the car.
 
Dr.Jeff said:
As a highly qualified nut, my suggestions are to hack up the engine bay, rear trunk, bulkhead, side scoops, engine lid, and rear tail light panel. Then add large side scoops, a open type engine lid, a rear panel grill, and a large electric fan to move air from the engine bay, through the now open rear trunk, out the back end of the car.
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They have cars like that, they are called "Beetles" and "Porsches." :D
 
Integrale said:
Have you considered an electric water pump? Would be able to move more water when idling than mechanical.
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I really like the idea of that Davies-Craig electric pump system, but not sure how well it would work in a system like ours with a bypass thermostat. I think it's more suited for systems with single action thermostats, but I could be wrong....
 
Conda said:
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.
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Huss tried this. If I recall it worked but was awkward to work around(?). The other idea with blowers by the side scoops also sounds good. I believe the topic here is not about engine cooling (e.g. water circulation), but engine bay cooling (e.g. air circulation).
 
Dan Sarandrea (Phila) said:
I really like the idea of that Davies-Craig electric pump system, but not sure how well it would work in a system like ours with a bypass thermostat. I think it's more suited for systems with single action thermostats, but I could be wrong....
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There is no thermostat with the davis craig system.
 
I really like the bilge pump idea on intakes, i might go for that along with seeing if i can make the rain tray removable. I got extra switches that need jobs!

And yes we were in Toronto. Kingston road was the hardest on the car cause we got stuck there during rush hour.

And for all you sciencey "needing proof" people I'll put a remote temp sensor back there to prove I'm not a nut. (Or prove i am one)
 
Conda said:
And yes we were in Toronto. Kingston road was the hardest on the car cause we got stuck there during rush hour.
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ah! I would have loved to meet you - next time! (plus there's a few members out in Kingston!) My X1/9 doesn't love idling in heavy traffic, needle goes way up just below the red! (even though my system is bled properly, etc etc.. )
 
myronx19 said:
My X1/9 doesn't love idling in heavy traffic, needle goes way up just below the red! (even though my system is bled properly, etc etc.. )
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Conda said:
Mine as well, i also noticed my gauge goes up about a needle width when i turn on the headlights!
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I know the topic of the engine cooling system has been beat to death, and this wasn't this initial subject of this thread. But since these recent comments have brought it up, in my opinion the design of the X's cooling system is borderline at best and could use some assistance on even a stock engine, let alone a performance one. I'm not talking about the radiator being clean or the the thermostat in good shape or any other normal maintenance item...those are assumed to be in proper order. I am suggesting going beyond stock to offer the system some "headroom" in situations where the engine temps start to rise (such as the ones described in the above posts). This might include a oversized radiator, higher performing electric fans (plural) on the rad, lower temp control switch for those fans, lower temp thermostat, increased air flow in/around the engine bay (as this thread is discussing), etc.

The thermostat will determine the engine's actual operating temperature, provided the coolant is BELOW that temp at all times. So even if you like to run the hot/stock spec thermostat, you need to be sure the rest of the system (rad, fans, water pump, pipes, etc) is capable of maintaining a coolant temp BELOW the thermostat temp. The thermostat will control the engine temp from there, by allowing less circulation - therefore warming the engine up to the desired temp - when it is below that, or allowing more circulation - to cool it - when the engine temp is above that. However if the coolant temp is higher than the thermostat temp, then it cannot make things cooler. In other words, the thermostat can always make the engine hotter, but it can only make it cooler if the coolant temp is lower.

Two vital aspects of this (aside from the radiator) are the electric fans and the control switch for them. Especially at a standstill or stop and go traffic, the fans need to be able to provide enough air circulation across the radiator to maintain a desired temp level (heat exchange). If the radiator's capacity to transfer heat is marginal, then even greater air circulation by the fans is needed. Since the fans are controlled by the electric switch (radiator sensor), it should be a LOWER temp than the thermostat's temp by at least a few degrees. Otherwise the system can never keep up with the demand (hince "headroom").

The water pump is also a vital component of the cooling system, but once again it cannot make up for a high coolant temp to overcome rising engine temps. Just like the thermostat, a electric water pump can warm up the engine by slowing down the coolant circulation. But it can only lower the engine temp IF the coolant's temp is BELOW the desired temp. All of the added circulation in the world will not lower the engine's temp if the coolant being circulated is hotter than the engine. So the radiator end of the system will always be the weak link, because that is where the actual heat is removed from the system (and therefore the engine).

If better fans and a lower fan control temp switch cannot reduce the coolant temp sufficiency, then the radiator itself needs to be increased to provide greater heat transfer. Remember your high school physics? - three types of heat transfer and the efficiency of each type?
 
My 2 cents. And not worth a penny more. My reasoning for wanting a cooler engine bay is because my intake is there. My engine temp (once i got the dang honda to fiat figured out) was never an issue. But i did want a cooler intake temperature. When i had the stock 1500, i once removed the carb fan. Talk about vapor lock. Rather than trying putting it back on, i tried the rain tray delete. Vapor lock issue seemed to go away. Key being seemed. The b swap happened soon after.
Not to mention there was a reason the fan was there. Fiat knew that the bay ran hotter than the engine did when it was in the 128. Rain tray delete wasnt an option because these cars were supposed to be daily drivers. Sun, rain, snow.

Again. Thoughts, observations and no science.

Odie
 
Pulling air up is the way to go. I experimented with this years ago. What I did as a final solution was to build a 7" fan into the cover. Mine has a thermoswitch and timer to keep it running for pre-set (by me) duration. Typically turns on right after coming to a stop after a highway run.

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Integrale said:
There is no thermostat with the davis craig system.
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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.
 
Dan Sarandrea (Phila) said:
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.
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One would need to remove the thermostat housing and go to an outlet only with fittings for the sensors (if fuel injected) and then plumb into the back of the old WP housing using the existing pipe across the back of the engine. So no split housing to uncontrollably meter fluid to the engine and the radiator.

All flow would go to the radiator, back to the pump and then into the engine. The heater return would need to move from the cross tube to feed into the pump directly as the current position would be on the pressure side making it a static loop.
 
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