Oil Cooler?

Ozzy wrote:

Jack of Hearts wrote:

Ozzy wrote:

Jack of Hearts wrote: I would run a thermostat on a oil cooler. No matter if it was air or water cooled.

Can I ask why? I can understand with an oil->air as it would increase the warm up time of the oil without a thermostat but with oil->water you lose the faster warm up benefit of having the better oil->water cooler... It would result in worse engine wear at startup in that instance...

Definitely run a thermostat with oil->air cooler though...

Like you mentioned in your earlier post. Water warms up faster then oil. You have the potential of the oil cooler actually cooling the water down. If your water is running at 90 and the oil is running at 50 (hypothetically) the higher heat from the water will be transferred to the oil. Slowing the warm up temp of the water.

For a price a thermostat? I'd run one

the water cooling actually has a benefit as well with the K-Series, as HGF often occurs with larger temperature deltas between the oil and water, and this can regularly result in hot spots...

it is actually massively beneficial for the oil and water to be at the same temperature or as close as possible all the way through the warm up cycle... this means lower temp delta and no hot spots which results in a lower chance of HGF...

i dont see why slower warming up water is an issue? you just dont boot it until it is up to temp, and oil is over 70Cish...

there is no down side that i can tell... the biggiest cause of HGF on the K-Series is temperature differences across the block and head.

Oz.

Why not let the oil get to temp on its own before cooling it down? I don't see why you would increase warm up time for the sake of a 20quid part?

Jack of Hearts wrote:

Ozzy wrote:

Jack of Hearts wrote:

Ozzy wrote:

Jack of Hearts wrote: I would run a thermostat on a oil cooler. No matter if it was air or water cooled.

Can I ask why? I can understand with an oil->air as it would increase the warm up time of the oil without a thermostat but with oil->water you lose the faster warm up benefit of having the better oil->water cooler... It would result in worse engine wear at startup in that instance...

Definitely run a thermostat with oil->air cooler though...

Like you mentioned in your earlier post. Water warms up faster then oil. You have the potential of the oil cooler actually cooling the water down. If your water is running at 90 and the oil is running at 50 (hypothetically) the higher heat from the water will be transferred to the oil. Slowing the warm up temp of the water.

For a price a thermostat? I'd run one

the water cooling actually has a benefit as well with the K-Series, as HGF often occurs with larger temperature deltas between the oil and water, and this can regularly result in hot spots...

it is actually massively beneficial for the oil and water to be at the same temperature or as close as possible all the way through the warm up cycle... this means lower temp delta and no hot spots which results in a lower chance of HGF...

i dont see why slower warming up water is an issue? you just dont boot it until it is up to temp, and oil is over 70Cish...

there is no down side that i can tell... the biggiest cause of HGF on the K-Series is temperature differences across the block and head.

Oz.

Why not let the oil get to temp on its own before cooling it down? I don't see why you would increase warm up time for the sake of a 20quid part?

because whilst the oil is thicker and cooler it is not protecting the engine, so the faster you can heat the oil the less damage you do to your engine whilst it warms up...

its the reason that you pre-heat an F1 cars oil... (that and the fact the block wont actually move when its cold as the tolerances are so tight!) lol!

less engine wear, and less temp difference between luck warm oil and red hot coolant... makes for a much more reliable car.

bensewell wrote: This is turning out to be an interesting thread? My £5.00 oil cooler might be a go then

Which oil cooler is it Ben?

Pics?

My mate is breaking his nova turbo and has a 9 core small cooler I can 'borrow' with all the plumbing and if.it fits then a few pints will sort him straight -) that's as much as I know he said something about mocul or something will look at it first

But with the water temp down your not going to be thrashing the engine anyway? Your warning the oil at the expense of the water. On a k series that's a risky move.

I see your thinking I just disagree with it

Been quietly following this thread with interest!

As a lecturer in fluid thermodynamics among other equally boring subjects as well as being a long standing car and bike tinkerer I have my own views with regard to oil/water specific heats and heat transfer.......but being a born-again non-argumentative person I will keep shtum....

However, I will say is that Mocul are a respected maker of oil cooler kits and also supply major manufacturers.

I had this very doubt when I was about to purchase my oil cooler (In my case not a 20quid part)
What is actually better? Water to Oil or Air to oil...
Bearing in mind the TF 160 has already a water to oil cooler but it's not the perfect system... I asked Mr. Blackoctagon about this very same question and here you have his aswer :broon:

I think it is enlighting for non engineers drivers:

PS: I am relocating to Spain and intention of doing many track days over there. :yesnod:


Mr Sergi,
If heat removal in a hot climate with a high duty is the only consideration then I would choose the crossflow heat exchanger type (Air to oil) as it will give the best temperature differential and the reduced fluid-to-fluid heat transfer coefficient that results from air-to-oil will be more than compensated by the extended surface area.


I'll assume you have no engineering background -

The transfer of heat between two fluids is dependant on
1. The surface area between the two fluids (the meniscus),
2. the thermophysical properties of the fluids,
3. the thermophysical properties of the meniscus,
4. the difference in fluid temperatures.

You then have to overlay that with the flow rates and thus the velocity of the fluids - this impacts how the fluid flows over the surface (turbulent or laminar)

You can safely assume that the flow rates of the air, water and oil will be such that the flows will all be turbulent.

A air-to-oil cooler has a poor fluid thermophysical behaviour, a good material one, and a good surface area. It also has a good big temperature differential - Lets say 110oC oil and 30oC air.

The water-to-oil cooler has a smaller surface area, good fluid thermophysical properties and a good material one. It has a smaller temperature differential - Let's say 110oC oil and 95oC water.

On that balance the air-to-oil is the better unit.


The advantage to the water-to-oil unit is that it creates less pressure drop in you oil system, so the delivery pressure of oil to the bearings and cam is higher and so it supports more load and prevents wear better.

BUT hotter oil supports less load.

This means that although the air-to-oil will give less delivery pressure it will give cooler oil that supports load betterl.

In competition and OEM engine design for high performance vehicles we would do experiments, and perhaps choose the air-to-oil, but flow/modify the oil pump to try to get back some of the pressure.


On the basis of the above, and assuming you really will be driving hard, for a good distance, in high heat i'd have to recommend the air-to-oil unit.
For me here in Scotland where it is rarely warm, and who does not race I would choose the water-to-oil unit.

I hope that all explains the reasons for my answer.



PS2: I am upgrading the oil pump as he suggested :beer:

Ah and my air to oil cooler is MOCAL as stated

This is turning out very educational for me -) you clever sods

When I mentioned 20quid part I was refering to the thermostat not the whole system :coat:

Sergi Bmw wrote: I had this very doubt when I was about to purchase my oil cooler (In my case not a 20quid part)
What is actually better? Water to Oil or Air to oil...
Bearing in mind the TF 160 has already a water to oil cooler but it's not the perfect system... I asked Mr. Blackoctagon about this very same question and here you have his aswer :broon:

I think it is enlighting for non engineers drivers:

PS: I am relocating to Spain and intention of doing many track days over there. :yesnod:


Mr Sergi,
If heat removal in a hot climate with a high duty is the only consideration then I would choose the crossflow heat exchanger type (Air to oil) as it will give the best temperature differential and the reduced fluid-to-fluid heat transfer coefficient that results from air-to-oil will be more than compensated by the extended surface area.


I'll assume you have no engineering background -

The transfer of heat between two fluids is dependant on
1. The surface area between the two fluids (the meniscus),
2. the thermophysical properties of the fluids,
3. the thermophysical properties of the meniscus,
4. the difference in fluid temperatures.

You then have to overlay that with the flow rates and thus the velocity of the fluids - this impacts how the fluid flows over the surface (turbulent or laminar)

You can safely assume that the flow rates of the air, water and oil will be such that the flows will all be turbulent.

A air-to-oil cooler has a poor fluid thermophysical behaviour, a good material one, and a good surface area. It also has a good big temperature differential - Lets say 110oC oil and 30oC air.

The water-to-oil cooler has a smaller surface area, good fluid thermophysical properties and a good material one. It has a smaller temperature differential - Let's say 110oC oil and 95oC water.

On that balance the air-to-oil is the better unit.


The advantage to the water-to-oil unit is that it creates less pressure drop in you oil system, so the delivery pressure of oil to the bearings and cam is higher and so it supports more load and prevents wear better.

BUT hotter oil supports less load.

This means that although the air-to-oil will give less delivery pressure it will give cooler oil that supports load betterl.

In competition and OEM engine design for high performance vehicles we would do experiments, and perhaps choose the air-to-oil, but flow/modify the oil pump to try to get back some of the pressure.


On the basis of the above, and assuming you really will be driving hard, for a good distance, in high heat i'd have to recommend the air-to-oil unit.
For me here in Scotland where it is rarely warm, and who does not race I would choose the water-to-oil unit.

I hope that all explains the reasons for my answer.



PS2: I am upgrading the oil pump as he suggested :beer:

...I could argue against some of these conclusions with regard to the specific heat capacity of air and laminar flow.....but I wont! All I will say is that I would go for oil/water....

Sergi Bmw wrote:
BUT hotter oil supports less load.

This means that although the air-to-oil will give less delivery pressure it will give cooler oil that supports load betterl.

that is only true for a certain window of oil temp, ie greater than (lets say picking a random number) 120C, this number will vary on the grade of oil used in the engine, and if it is a mineral of synthetic type...


but yes i agree with the rest you said

oil -> air with a thermostat in racing may give a marginal advantage, but lotus's 24Hr Evora endurance racer GT2, GT3 and GT4 cars all use twin Laminova OIl -> Water coolers as it provides a better thermal working temp for the whole system without random high and low points at lower and faster velocities, thus creating a more consistant working temp, and a lower delta between the oil and water, thus prolonging the life of the engines....

they run this set up on their 280bhp GT4 and 440bhp GT2... both with great results...

personally i would go for oil -> water every time and if my temps were getting too high invest in a higher flow radiator and water and oil pumps...

again my 2p's worth.

Oz