Christian_83
Xscream
- Location
- Denmark
Freestyle Extra cylinder cooling
- Thread starter loictahiti
- Start date
- Location
- Charlotte NC
Well i disagree with you, water is a very good heat transfer medium. So only downside i would see from flowing to much water, would be cold engine
But i do agree that most people properly are overthinking this
Actually he is very correct. It takes time for the water to absorb the heat from the cylinder. You also have to factor in incoming water temp and how much heat you can transfer to the water.
Christian_83
Xscream
- Location
- Denmark
Let me get this straight. So you think you can flow to much cooling water through and engine, and that way the engine will overheat?
loictahiti
Site Supporter
- Location
- Tahiti, french polynesia
Cristian83 we haven’t same problem, you live in Denmark, me in Tahiti , its not the same water temp ahahahahaaha
Seriously, my idea about this post is not about good or not engine temp, is just how you do with waterpipe and water distributor to keep engine bay clean ....
On side, for the good cooling temp is ajust water volume and time (or water speed) , its called thermic exchange ,
Seriously, my idea about this post is not about good or not engine temp, is just how you do with waterpipe and water distributor to keep engine bay clean ....
On side, for the good cooling temp is ajust water volume and time (or water speed) , its called thermic exchange ,
Christian_83
Xscream
- Location
- Denmark
lol thats funny
at least i dont believe that you can cool a engine to the point it overheats turbulence in cooling water and raising speeds, actually removes a boundary layer between the water and cylinder and will increase the heat transfer
@loictahiti I know that we got diffrent water temps
I didnt get, that you mainly were looking for options for your wet pipe, thought you asked to more cooling for you engine
Magnum Mike
Site Supporter
Time has nothing to do with the rate of heat flow since you are taking the limit as t->0 to get the rate.
Newton's Law of Cooling
Newton's Law of Cooling states that the rate of change of the temperature of an object is proportional to the difference between its own temperature and the ambient temperature (i.e. the temperature of its surroundings).
If the water in the cooling system is being replaced faster I think that water would be cooler than water flowing out of the same system at a slower rate. There would be more water at the higher flow rate so a larger amount of heat would be transferred even though the water is exiting at a lower temp than a slower and warmer pisser.
- Location
- Charlotte NC
So if the water is moving too quickly through the system how much time does it have to remove the heat?
Christian_83
Xscream
- Location
- Denmark
But how should the water "move to quickly" to transfer heat?
It dosent make sense lol
DAG
Yes, my balls tickled from that landing
- Location
- Charlotte, NC
Ever seen water dance on a frying pan?
Christian_83
Xscream
- Location
- Denmark
- Location
- Uk
I learnt this a good few years ago and was surprised.
We changed a head on a 3516 v16 caterpillar 68litre gas engine.
Filled it back up with water and just opened the valves up full bore as we thought they were.
The engine should run at 110deg c outlet temp, we had over 120 deg c.
Spoke to the guy that looked after it and he said he outlet valve needs to be closed back to slow the flow and allow the heat transfer.
Closed the valve back and temp dropped.
Wouldn’t have believed it my self until I saw it.
We changed a head on a 3516 v16 caterpillar 68litre gas engine.
Filled it back up with water and just opened the valves up full bore as we thought they were.
The engine should run at 110deg c outlet temp, we had over 120 deg c.
Spoke to the guy that looked after it and he said he outlet valve needs to be closed back to slow the flow and allow the heat transfer.
Closed the valve back and temp dropped.
Wouldn’t have believed it my self until I saw it.
- Location
- South Africa
There needs to be a certain amount of pressure in the system to counteract the heat coming through from expanding the gases in the water boundary layer and forming an insulation layer. Air is a very effective insulatorNo i dont think so
But to get it straight, are you saying that if the cooling flow is high enough, the water will not transfer the heat - and make the engine overheat due to this fact?
- Location
- Valley Springs, CA
Soooo much overthinking here lol, I would honestly contact either TC or Kyle for Dasa routing.
DAG
Yes, my balls tickled from that landing
- Location
- Charlotte, NC
I like the discussion on water flow, water pressure and cooling interesting and informative. But getting back to what the OP is asking about, the routing waterlines on a Dasa cylinder with extra cooling.
We have 4 extra cooling lines on our Dasa cylinder. It's a TC Freeride built XFS with a Dasa 1000. The distribution block was an option, but not required by Taylor or Kyle at Dasa. I had Taylor include it in our build because a freestyle engine is expensive engine to purchase and maintain and we wanted every engine protection possible.
By it's nature a freestyle ski's engine is built to provide maximum power which also naturally increases the cooling requirements of the engine. To add to that the ski spends a lot of time spinning around in the air and going upside down, all of this while running without a cooling water supply. At times between tricks the pump has only 1 or 2 seconds back in the water to re-gain thrust for the next trick. In those seconds I can only imagine how little water actually makes it thru the cooling system and fills the water jackets, let alone providing flow to cool the engine. This lack of cooling is at a time you are also asking the engine to produce max power in burst after burst after burst.
By using a distribution block you are just trying to insure that in the few seconds you do have an available water supply, it is routed directly not only to the exhaust manifold (then to the cylinder) but also flowing directly to the cylinder itself. Taylor builds an awesome ski and the system he runs system works great.
I don't claim to be an expert on cooling or freestyle skis and I'm perhaps I'm overthinking it, but it seemed like a goot option to me.
We have 4 extra cooling lines on our Dasa cylinder. It's a TC Freeride built XFS with a Dasa 1000. The distribution block was an option, but not required by Taylor or Kyle at Dasa. I had Taylor include it in our build because a freestyle engine is expensive engine to purchase and maintain and we wanted every engine protection possible.
By it's nature a freestyle ski's engine is built to provide maximum power which also naturally increases the cooling requirements of the engine. To add to that the ski spends a lot of time spinning around in the air and going upside down, all of this while running without a cooling water supply. At times between tricks the pump has only 1 or 2 seconds back in the water to re-gain thrust for the next trick. In those seconds I can only imagine how little water actually makes it thru the cooling system and fills the water jackets, let alone providing flow to cool the engine. This lack of cooling is at a time you are also asking the engine to produce max power in burst after burst after burst.
By using a distribution block you are just trying to insure that in the few seconds you do have an available water supply, it is routed directly not only to the exhaust manifold (then to the cylinder) but also flowing directly to the cylinder itself. Taylor builds an awesome ski and the system he runs system works great.
I don't claim to be an expert on cooling or freestyle skis and I'm perhaps I'm overthinking it, but it seemed like a goot option to me.
If anybody cares, there are physical reasons for both what Christian is saying and what the other few folks are says.
Higher flow = more heat transfer, or more accurately higher velocity = more heat transfer. Always, there is no such thing as moving too fast so heat can't transfer.
BUT
Often you need a restriction. For example lots of engines with thermostats will start having overheating issues if you remove the thermostat.
The reason is not flow rate, it's pressure.
If you have cavitation, or a local hot spot where the coolant boils, you have a pocket of gas (steam) which is an insulator. A restriction increases the pressure, increasing the boiling point, and also reduces the velocity which tends to reduce cavitation.
Also, with higher flow rate you'll have less change in temperature from inlet to outlet, the reason is that the same amount of heat energy is put into a higher volume of coolant, so coolant doesn't get as warm, even though it's carrying away the same or more heat.
If you have a closed system with a radiator, the same thing happens on the radiator side, so you end up with higher flow rate = higher temp into motor, lower temp out of motor, lower temp into radiator, higher temp out of radiator. That makes it look like less heat is exchanged, but really it is not. In a closed system the average temp of the whole system is the same (or lower) but everything is closer to the average temp.
Also, I dont know dick about freestyle ski cooling systems so like they say above, talk to engine builder or ski builder.
Higher flow = more heat transfer, or more accurately higher velocity = more heat transfer. Always, there is no such thing as moving too fast so heat can't transfer.
BUT
Often you need a restriction. For example lots of engines with thermostats will start having overheating issues if you remove the thermostat.
The reason is not flow rate, it's pressure.
If you have cavitation, or a local hot spot where the coolant boils, you have a pocket of gas (steam) which is an insulator. A restriction increases the pressure, increasing the boiling point, and also reduces the velocity which tends to reduce cavitation.
Also, with higher flow rate you'll have less change in temperature from inlet to outlet, the reason is that the same amount of heat energy is put into a higher volume of coolant, so coolant doesn't get as warm, even though it's carrying away the same or more heat.
If you have a closed system with a radiator, the same thing happens on the radiator side, so you end up with higher flow rate = higher temp into motor, lower temp out of motor, lower temp into radiator, higher temp out of radiator. That makes it look like less heat is exchanged, but really it is not. In a closed system the average temp of the whole system is the same (or lower) but everything is closer to the average temp.
Also, I dont know dick about freestyle ski cooling systems so like they say above, talk to engine builder or ski builder.
