Cooling idea opinions

[Brd.Prey]

What do you guys think about plumbing the out from my AWIC to the inlet of the fluid to fluid oil cooler. Then plumb the out of the oil cooler to the AWIC radiator? I think the mounted in the very front radiator should be able to coole the extra temp the oil cooler adds. This will reduce engine cooling load + maybe even cool the oil better.

Ok, what am I missing?

[iblackwe]

I think thats a great idea! Because your intake air temperatures through the intercooler are around 20*C and your oil temps are around 100*C you would probably see quite the drop in oil temp and I don't know what the optimal temperature would be. Also would there be any major restrictions through the oil cooler radiator vs the AWIC radiator, I am sure the pump would handle it but you would also want to be able to maintain a good flow for the AWIC

[Rob T]

Hi: With my system, which is a front radiator AWIC driven by a 12V circulating pump to the engine compartment I see about ambient temp +10F for the AIR temp to the engine after the intercooler. What I don't know is if the radiator in front is returning the water back to ambient, or if the extra load from the oil cooler would drive the need for a bigger radiator in the front. I have a dry sump whose discharge line goes through an air to oil SETRAB cooler that is ducted with two ducts to the side scoops, before sending the oil to the Spintric and reservoir. There is fan assist controlled by thermostat as well on the air to oil cooler. Where I was running my car, I would see 105F days and 60F days. I typically ran 20 minute sessions. My biggest heat challenge was with the 5MT. On the short track in NM at 80-85F outside temp, I saw 102 after the AWIC, engine coolant temps of 190. Oil temps of 205-215 and 225F on the 5MT using an infrared.

[Brd.Prey]

I agree, my concern is the heat load removing capacity of the Radiator (AWIC). Will it still be able to pull water temps back to the same amount before the oil cooler was put in the loop. I am hypothesizing it would as there isn't that much of a load from the AWIC cooler. I was hoping someone here either did it this way or calculated the results. Otherwise I will be installing a bunch of temp sensors.

[Brd.Prey]

Where are those Mechanical Engineers

[Rob T]

I am a chemical engineer, sorry but I have never done this type of calculation. There are a few factors that will make a difference for sure. Ambient temp outside. Velocity of air over the radiator and the capacity of the radiator. Also, the difference between ambient temperature and temperature of the fluid drives how much heat will be removed for any given condition. When I used to run at Buttonwillow, there were great sections of high speed and ALL of my cooling worked better: car, AWIC, brakes. The track in Albuquerque is very tight with no real long straights or sweepers. Every thing ran hotter. A small detail, but directionally correct is that your circulating pump will put heat into your water as well. An easy way to estimate it (not exact) is to calculate the power draw of the pump. That energy is going into the water. If the fluid dynamics work and you can avoid cavitation, having the pump before the radiator will give you the most cool water.

[Brd.Prey]

Good info, especially about pump location.

[UnhipPopano]

First, It is normal in sizing to at least go one size larger and is referred to as margin [Engineering/Error/etc]. Then you have the long runs from the back of the car to the front, and that adds additional cooling. If you look at the size of an oil cooler, they are not very big. So from a heat exchange standpoint, you are probably alright, and can verify this by monitoring your air inlet temperature.

Now from a safety standpoint and if you had a leak, would the oil leak into the coolant or would you get coolant in the oil?

[Ajzride]

Now from a safety standpoint and if you had a leak, would the oil leak into the coolant or would you get coolant in the oil?

I'm new to the Subaru engines, but I'm guessing the oil is going to be running 30+ PSIG, if your coolant gets hot enough to build more pressure than that, you have bigger problems. So in the event of a leak you will have oil in your coolant.

[Bob_n_Cincy]

What do you guys think about plumbing the out from my AWIC to the inlet of the fluid to fluid oil cooler. Then plumb the out of the oil cooler to the AWIC radiator? I think the mounted in the very front radiator should be able to coole the extra temp the oil cooler adds. This will reduce engine cooling load + maybe even cool the oil better.
Ok, what am I missing?

This doesn't make sense to me. You are just sharing some of the engine load with the awic radiator.

If you need help with engine cooling, put a bigger/better engine radiator in it.
If you need more awic cooling, put a bigger/better awic radiator in it.


Why complicate the system by sharing?

This is mine: rad.jpg

Bob

[Brd.Prey]

I was going to use a water to oil cooler anyway. So sharing was gonna happen. The Oil cooler on the installations I have read about on here were plumbed into the return radiator plumbing (which adds heat to the water heading into the engine. My idea at leasts pulls the heat from the oil and then runs the water to the AWIC radiator where if the cooling capacity is high enough then then water entering the AWIC will be the same temp as with no oil cooler. To me it is a question of what has more reserve cooling capacity. As far as to much PSI oil coolers that use liquid are made for that kinda load. We have been running transmission oil into radiators for years.

[Brd.Prey]

This doesn't make sense to me. You are just sharing some of the engine load with the awic radiator.

If you need help with engine cooling, put a bigger/better engine radiator in it.
If you need more awic cooling, put a bigger/better awic radiator in it.


Why complicate the system by sharing?

This is mine: rad.jpg

Bob

PIC is that an AWIC radiator out front or an intercooler? It is huge!

[Bob_n_Cincy]

PIC is that an AWIC radiator out front or an intercooler? It is huge!

The front dual core radiator is for a VW Scirocco used to cool the AWIC fluid. It's not really that big. The rule of thumb I use is: Make the cooling capacity of the AWIC radiator bigger than the air to air intercooler.
https://www.ebay.com/itm/2-ROW-ALUMI...del%3AScirocco

[Brd.Prey]

Nice, pretty sure that would do it!

[STiPWRD]

I'm with Bob on this one, I would leave the oil and intake air coolers on separate loops. Also, I'm an ME and have designed a few heat exchangers. Without knowing the heat load coming from the oil or the flow rate of the AWIC loop, it's tough to really do any calculations.

In general, the engine wants to see air temps as cold as possible (or as close to ambient) and oil temps considerably higher than that. For example, let's say your intake air temp is 70F and oil temp is 180F; by putting those two things on the same coolant loop, you're sharing the total heat load and the coolant temperature will equalize somewhere between the two even after going through the front liquid-to-air heat exchanger. So, I'm not saying it's not going to work but just sounds like you're sacrificing IAT's at the benefit of cooler oil temps. I'm not sure how much benefit that adds over a simple oil to air cooler on a separate loop.

[UnhipPopano]

I agree with art that it would be best to keep things separate, but I do not agree with how the temperatures would be. If the radiator/heat exchanger is sized correctly, the outlet temperature should be 5-10 degrees higher than ambient. This would now go into the AWIC and get heated up some unknown amount based on the engine load [mass of air] and turbo compression [Temperature-Pressure relationship of air]. This would now go into the oil cooler somewhat below the 180 degrees. If the oil cooler is Full Flow, then the oil temperature will normally be below where you want, and you will need some type of control to either divert some of the coolant or bypass of the oil to the exchanger.

The engine cooling loop has a thermostat that in effect reduces the efficiency of the cooling to maintain the coolant and engine at a high enough temperature, but not too hot. The AWIC loop wants the temperature as low as possible, and the Oil cooler wants to just shed any excess heat. In this I agree with STIPWRD that a separate unit for the oil would probably work best [KISS].

[Brd.Prey]

Ok, great point will probably keep it separate. It also appears cheaper.

[Rob T]

One other thing to consider is protection for your radiators. Mine were getting "shelled" at the track from tire debris and rocks. I put a thin NOMEX honeycomb over the front of the radiators and it works like magic. The material is very tough and it is also very open, so it has little impact on the efficiency of the radiators. It is sold for dirt track racers.

[Mitch Wright]

I am with some of the others I would run my oil to water exchanger through the engine radiator. A) to make sure the coolant to the IC is as cool as possible. B) the cooling system has more than enough capacity for the engine and the water to oil cooler. My 2 cents.

[Brd.Prey]

Mine were getting "shelled" at the track from tire debris and rocks.

You got out front man in the cool clean air! Just kidding! LOL