So ive said this before and got chased away but here it goes again. A plastic undertray would help with cooling I think. It helps to increase the pressure delta from in front of the rad to behind it. This means air WANTS to go thru the rad more because there is LESS RESISTANCE. That paired with some proper shrouding to force air through the rad seems like the ultimate solution. Thin aluminum sheets and Aluminum tape is awesome for that.
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Finally had heat management problems :/
- Thread starter Ptuning_Nate
- Start date
I don't think your logic is flawed. You also get far better aerodynamics up front with the tray. One thing I learned from a rally team is not seal up the tray too much without having proper evacuation for the heat in the engine compartment. This was being said while standing in front of a Mazda3 rally car that was burned up from the firewall forward. You are 100% spot-on with the shrouding and aluminum tape. That is what I have done in the past. I started with paper to make the template and then cut the aluminum. The openings were all sealed with aluminum tape. My next plan was to install extractor vents, but the engine runs too cold, so I haven't done anything more to improve cooling. The plastic shrouding on the Fiesta is already pretty good, so it probably wouldn't take much to seal it up even better. I would start with the area around the intercooler and seal that to the bumper first. Then seal up the sides going to the radiator and all around the top of the plastic shroud.
I would be curious if somebody extended the length of the flap under the radiator closer to the ground to see what affect that has. You could start with some garden edging bolted to the factory flap to see if there is any improvement.
I finally had my first run in with hot temps in my ST. Tuesday the air temp skyrocketed to 98'F! For West Michigan, we go years at a time without ever reaching 90'F. Roads have buckled, draw bridge broke open, sections of roads closed due to damage. I saw 225'F coolant, 230'F oil (which isn't too bad), and the Mountune intercooler did great at keeping the charge temp at 110'F. The intake temp was over 120'F. Until Tuesday, my ST has only seen a water temp around 205'F. It typically runs 197'F all summer long. The coolant temp really gave me a scare! Being so hot, I got home and jumped in my Mustang to take advantage of the heat. It loves to run in the hot air and I was able to get the oil over 210'F and coolant to 185'F. It was a great way to check to make sure everything works after being in storage since last September.
I would be curious if somebody extended the length of the flap under the radiator closer to the ground to see what affect that has. You could start with some garden edging bolted to the factory flap to see if there is any improvement.
I finally had my first run in with hot temps in my ST. Tuesday the air temp skyrocketed to 98'F! For West Michigan, we go years at a time without ever reaching 90'F. Roads have buckled, draw bridge broke open, sections of roads closed due to damage. I saw 225'F coolant, 230'F oil (which isn't too bad), and the Mountune intercooler did great at keeping the charge temp at 110'F. The intake temp was over 120'F. Until Tuesday, my ST has only seen a water temp around 205'F. It typically runs 197'F all summer long. The coolant temp really gave me a scare! Being so hot, I got home and jumped in my Mustang to take advantage of the heat. It loves to run in the hot air and I was able to get the oil over 210'F and coolant to 185'F. It was a great way to check to make sure everything works after being in storage since last September.
before some go wasting their time.
http://www.fiestastforum.com/forum/threads/7265-Aero-mods-and-cooling?highlight=undertray
http://www.fiestastforum.com/forum/threads/7265-Aero-mods-and-cooling?highlight=undertray
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“Also took three measurements on hood exterior where WRC rally vents are located, -1.7, -2.0 and -2.8"
Things that surprised me:
1. Our hood has positive pressure up center hump, and I assumed the hump was for style. Maybe not. Slight positive pressure negates lift at speed.
2. High negative pressures on hood surface and sides adjacent to rear half of headlights where WRC rally vents are, even though I found slight negative pressures beneath hood in this area (-0.2 to -0.3) in first report of results, the strong pressure differential between underside and top says those vent locations would pull air from engine bay.
3. Measurements down length of roof to hatch spoiler suggest the spoiler is not just for looks, it is helping reduce lift at speed.
Most surprising to me is the pressure differential between underside and exterior of hood where the WRC vents are. I am so stoked by these data, I want to cut holes and see what happens to the rest of the engine bay pressures. Theory says filling low pressure areas with ducted inflows improves aero.
But main thing remains finding more efficient ways to loose heat. These two low pressure areas look ideal. Delta 2" pressure gradient is tantalizing.”
I knew I had read this in here somewhere. Supports the WRC over centre bonnets vents I mentioned.
I have a fibre undertray off a diesel Fiesta that I plan on trying. But I may add an aluminium angle to act as a gurney flap to the trailing edge of it to increase the “suction” effect and to give it more strength when it gets wet. I’ve seen plastic trays advertised on eBay also but only after I bought this one.
Things that surprised me:
1. Our hood has positive pressure up center hump, and I assumed the hump was for style. Maybe not. Slight positive pressure negates lift at speed.
2. High negative pressures on hood surface and sides adjacent to rear half of headlights where WRC rally vents are, even though I found slight negative pressures beneath hood in this area (-0.2 to -0.3) in first report of results, the strong pressure differential between underside and top says those vent locations would pull air from engine bay.
3. Measurements down length of roof to hatch spoiler suggest the spoiler is not just for looks, it is helping reduce lift at speed.
Most surprising to me is the pressure differential between underside and exterior of hood where the WRC vents are. I am so stoked by these data, I want to cut holes and see what happens to the rest of the engine bay pressures. Theory says filling low pressure areas with ducted inflows improves aero.
But main thing remains finding more efficient ways to loose heat. These two low pressure areas look ideal. Delta 2" pressure gradient is tantalizing.”
I knew I had read this in here somewhere. Supports the WRC over centre bonnets vents I mentioned.
I have a fibre undertray off a diesel Fiesta that I plan on trying. But I may add an aluminium angle to act as a gurney flap to the trailing edge of it to increase the “suction” effect and to give it more strength when it gets wet. I’ve seen plastic trays advertised on eBay also but only after I bought this one.
Acting out by resorting to lame comments specifically intended to not contribute anything other than hurt someone else emotionally may make you feel good but what it really does is makes you look far worse than the person you're attacking.
More importantly, it is not only counter-productive and harmful to the FiestaSTForum.com community for people trying to have an informed discussion, it's also ABUSIVE behavior towards other members and should not be tolerated by the admins.
More importantly, it is not only counter-productive and harmful to the FiestaSTForum.com community for people trying to have an informed discussion, it's also ABUSIVE behavior towards other members and should not be tolerated by the admins.
It also helps to 'cook' the moisture, un-burned diluted fuel, and any other volatile 'light ends' out of the oil, especially in a car which sits for long periods of time, which helps prevent destructive acid buildup in the sump. 
My concern with using an aftermarket, air to oil type oil cooler (even WITH a thermostat) in a daily/winter driven car is that our factory oil/coolant type deal actually HELPS the oil get up to temp quicker in the cold ambient temps (even more critical yet for you, and others in the northern tier areas).
My concern with using an aftermarket, air to oil type oil cooler (even WITH a thermostat) in a daily/winter driven car is that our factory oil/coolant type deal actually HELPS the oil get up to temp quicker in the cold ambient temps (even more critical yet for you, and others in the northern tier areas).
It also helps to 'cook' the moisture, un-burned diluted fuel, and any other volatile 'light ends' out of the oil, especially in a car which sits for long periods of time, which helps prevent destructive acid buildup in the sump.
My concern with using an aftermarket, air to oil type oil cooler (even WITH a thermostat) in a daily/winter driven car is that our factory oil/coolant type deal actually HELPS the oil get up to temp quicker in the cold ambient temps (even more critical yet for you, and others in the northern tier areas).
My concern with using an aftermarket, air to oil type oil cooler (even WITH a thermostat) in a daily/winter driven car is that our factory oil/coolant type deal actually HELPS the oil get up to temp quicker in the cold ambient temps (even more critical yet for you, and others in the northern tier areas).
Stock oil cooler doesn't have a thermostat. That would be just another failure point. IIRC, it is on just the engine coolant loop that excludes the radiator when everything is cold...since it is mounted on the engine. So the oil cooler does two things.
When the coolant is warming up, it helps warm the engine oil up to temperature faster than it normally would otherwise. Then, when the oil temperature gets higher than the coolant, it acts as a way to shed heat. It is a fantastically simple design.
When the coolant is warming up, it helps warm the engine oil up to temperature faster than it normally would otherwise. Then, when the oil temperature gets higher than the coolant, it acts as a way to shed heat. It is a fantastically simple design.
Engine Cooling - System Operation and Component Description
System Operation
Engine coolant flows primarily from the engine to the radiator circuit and back to the coolant pump. Coolant is sent from the coolant pump through the engine block and cylinder heads. A separate circuit from the engine also feeds the heater core and turbochargers with coolant. The coolant pump, operated by engine rotation through the accessory drive belt, circulates the coolant. The coolant thermostat is a control valve actuated by coolant temperature. When the thermostat is closed, coolant flow bypasses the radiator circuit and returns to the coolant pump. When the thermostat is opened, coolant flows through the radiator circuit to transfer engine-generated heat to the outside air.
The degas bottle holds surplus coolant and removes air from the cooling system. It also allows for coolant expansion and system pressurization, replenishes coolant to the cooling system and serves as the location for service fill.
The thermostat monitor is a function of the PCM and is designed to verify correct thermostat operation. The monitor executes once per drive cycle and has a monitor run duration of 300-800 seconds. If a malfunction occurs, DTC P0125 or P0128 sets, and the MIL illuminates.
The engine's cooling circuit consists of an additional coolant bypass solenoid valve and coolant shutoff solenoid valve. Using these two valves, the coolant flow through the engine is specifically restricted or stagnated in the warm-up phase. This restriction of the coolant flow makes it possible for the engine components to warm up faster. The result is a significant reduction in the emissions of harmful pollutants and an improvement in fuel economy (i.e. reduced friction) during the warm-up phase. Both solenoid valves are controlled by the PCM .
The following input parameters are used to do this:
Coolant temperature
Ambient air temperature
Engine speed
Engine load
Status of the air conditioning system
Warm-up regulation is performed in four phases. Phase 1 or 2 occurs after initial engine start-up depending on the ambient air temperature.
Phase 1:
During an initial engine start-up with an ambient temperature is 60-75F (16-24C) or warmer (calibratable) the coolant shutoff solenoid valve closes and the coolant bypass solenoid valve remains closed. With both valves closed the coolant is stagnant and does not circulate in the engine (cylinder block and cylinder head) or through any other cooling system component to significantly decrease the engine warm up time. This reduces emissions and fuel consumption during warm-up.
Phase 2:
During an initial start-up with an ambient temperature 60-75F (16-24C) or cooler (calibratable) the coolant shutoff solenoid valve remains open. This allows engine coolant to circulate through the heater core providing cabin heat to the customer. When the coolant shutoff solenoid valve is open, the coolant circulates through the engine (cylinder block and cylinder head), heater core, engine oil cooler, transmission oil cooler, turbo, and degas bottle. Coolant is also routed into the thermostat housing which initiates the warm-up phase of the thermostat.
Phase 3:
The coolant bypass solenoid valve is energized and opens when engine coolant reaches (158F) 70C and the engine load is greater than 70% or engine speed is greater than 4,000rpm. When the coolant bypass solenoid valve opens coolant is routed through a coolant between the engine block output and thermostat housing. The opening of this coolant circuit increases the coolant flow rate through the engine block which reduces cooling system pressure and temperature fluctuations in the engine block.
Phase 4:
At about (194F) 90C, the thermostat opens and the coolant is routed through the radiator. However, the thermostat opening temperature is partially variable via the coolant bypass solenoid valve. The temperature around the thermostat and its expansion element is the total of the coolant temperatures entering the thermostat housing. Targeted actuation of the coolant bypass solenoid valve allows increased flow of coolant from the engine block to contact the thermostat element and allows an actual coolant temperature of between (194F) 90C and (212F) 100C to be set. During part throttle driving, fuel consumption depends heavily on coolant temperature. Closing of the coolant bypass solenoid valve makes it possible to drive with a higher coolant temperature during part throttle conditions.
Component Description
Coolant Shutoff Solenoid Valve
The coolant shutoff solenoid valve is an electrically controlled solenoid to allow or block the flow of engine coolant. This electrically controllable valve is normally open when not energized. The valve receives a fused 12V B+ supply when the ignition is in the run or start position and is grounded by the PCM via a low side driver. The PCM monitors the solenoid and circuits for electrical faults and sets an appropriate DTC .
Coolant Bypass Solenoid Valve
The coolant bypass solenoid valve is an electrically controlled solenoid to allow or block the flow of engine coolant. This electrically controllable valve is normally closed when not energized. The valve receives a fused 12V B+ supply when the ignition is in the run or start position and is grounded by the PCM via a low side driver. The PCM monitors the solenoid and circuits for electrical faults and sets an appropriate DTC .
Copyright © Ford Motor Company
System Operation
Engine coolant flows primarily from the engine to the radiator circuit and back to the coolant pump. Coolant is sent from the coolant pump through the engine block and cylinder heads. A separate circuit from the engine also feeds the heater core and turbochargers with coolant. The coolant pump, operated by engine rotation through the accessory drive belt, circulates the coolant. The coolant thermostat is a control valve actuated by coolant temperature. When the thermostat is closed, coolant flow bypasses the radiator circuit and returns to the coolant pump. When the thermostat is opened, coolant flows through the radiator circuit to transfer engine-generated heat to the outside air.
The degas bottle holds surplus coolant and removes air from the cooling system. It also allows for coolant expansion and system pressurization, replenishes coolant to the cooling system and serves as the location for service fill.
The thermostat monitor is a function of the PCM and is designed to verify correct thermostat operation. The monitor executes once per drive cycle and has a monitor run duration of 300-800 seconds. If a malfunction occurs, DTC P0125 or P0128 sets, and the MIL illuminates.
The engine's cooling circuit consists of an additional coolant bypass solenoid valve and coolant shutoff solenoid valve. Using these two valves, the coolant flow through the engine is specifically restricted or stagnated in the warm-up phase. This restriction of the coolant flow makes it possible for the engine components to warm up faster. The result is a significant reduction in the emissions of harmful pollutants and an improvement in fuel economy (i.e. reduced friction) during the warm-up phase. Both solenoid valves are controlled by the PCM .
The following input parameters are used to do this:
Coolant temperature
Ambient air temperature
Engine speed
Engine load
Status of the air conditioning system
Warm-up regulation is performed in four phases. Phase 1 or 2 occurs after initial engine start-up depending on the ambient air temperature.
Phase 1:
During an initial engine start-up with an ambient temperature is 60-75F (16-24C) or warmer (calibratable) the coolant shutoff solenoid valve closes and the coolant bypass solenoid valve remains closed. With both valves closed the coolant is stagnant and does not circulate in the engine (cylinder block and cylinder head) or through any other cooling system component to significantly decrease the engine warm up time. This reduces emissions and fuel consumption during warm-up.
Phase 2:
During an initial start-up with an ambient temperature 60-75F (16-24C) or cooler (calibratable) the coolant shutoff solenoid valve remains open. This allows engine coolant to circulate through the heater core providing cabin heat to the customer. When the coolant shutoff solenoid valve is open, the coolant circulates through the engine (cylinder block and cylinder head), heater core, engine oil cooler, transmission oil cooler, turbo, and degas bottle. Coolant is also routed into the thermostat housing which initiates the warm-up phase of the thermostat.
Phase 3:
The coolant bypass solenoid valve is energized and opens when engine coolant reaches (158F) 70C and the engine load is greater than 70% or engine speed is greater than 4,000rpm. When the coolant bypass solenoid valve opens coolant is routed through a coolant between the engine block output and thermostat housing. The opening of this coolant circuit increases the coolant flow rate through the engine block which reduces cooling system pressure and temperature fluctuations in the engine block.
Phase 4:
At about (194F) 90C, the thermostat opens and the coolant is routed through the radiator. However, the thermostat opening temperature is partially variable via the coolant bypass solenoid valve. The temperature around the thermostat and its expansion element is the total of the coolant temperatures entering the thermostat housing. Targeted actuation of the coolant bypass solenoid valve allows increased flow of coolant from the engine block to contact the thermostat element and allows an actual coolant temperature of between (194F) 90C and (212F) 100C to be set. During part throttle driving, fuel consumption depends heavily on coolant temperature. Closing of the coolant bypass solenoid valve makes it possible to drive with a higher coolant temperature during part throttle conditions.
Component Description
Coolant Shutoff Solenoid Valve
The coolant shutoff solenoid valve is an electrically controlled solenoid to allow or block the flow of engine coolant. This electrically controllable valve is normally open when not energized. The valve receives a fused 12V B+ supply when the ignition is in the run or start position and is grounded by the PCM via a low side driver. The PCM monitors the solenoid and circuits for electrical faults and sets an appropriate DTC .
Coolant Bypass Solenoid Valve
The coolant bypass solenoid valve is an electrically controlled solenoid to allow or block the flow of engine coolant. This electrically controllable valve is normally closed when not energized. The valve receives a fused 12V B+ supply when the ignition is in the run or start position and is grounded by the PCM via a low side driver. The PCM monitors the solenoid and circuits for electrical faults and sets an appropriate DTC .
Copyright © Ford Motor Company
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