Landracing Forum
Tech Information => Technical Discussion => Topic started by: sofadriver on March 09, 2015, 12:56:03 AM
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I'm thinking the best way to cool the little 100cc APS bike I'm building is to immerse the radiator in a water tank. I'm hoping someone might have a pic of a simple way to do it. Should I plan to circulate the tank water with a pump? Use ice? I'm clueless.
This little motor gets just as hot as any other race motor - it's just on a smaller scale :-)
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there are two ways---one is just a static radiator in a tank which evaporates water as the radiator passes the eng. heat to theis in
the other is a radiator in an enclosed box in which you pump cooling water in to and out of the box passing through the radiator fins My lakester build as several others including Hooley's Studie have build pictures.
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With only a 100 cc motor and with the room you have in your frame why not just a nice cylindrical tank that holds 2-3 gallons of water, put a pressure cap on it and run some ice in the tank, use a thermostat and use a small electric water pump to circulate the water from the tank through the engine. With a really good 100 cc motor you might be at 25-30 hp which make the water heat load max of about 10 hp so a 5 gpm pump (rated at 5 gpm at the pressure drop through your motor) would do it. The complexity of a radiator in a tank system just does not seem warranted for your application. If your must have some sort of radiator/heat exchanger then look into plate style heat exchangers, they are much smaller and more efficient than any of the "radiator in a box" systems and much smaller. There is a guy that runs a 350/400 Yamaha YZ-400 twin that is water cooled (this engine is probably good for 80-100 hp)and he uses a plate style heat exchanger and it is probably not bigger than 3 x 4 x 10 inches and it keeps his engine very cool, it is tucked up under his rear seat extension.
Rex
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Mike, I have to agree with Rex. There is no need for the complexity of a radiator in a box. I ran a water tank (no radiator) on my turbo Hayabusa. It held about 8 gallons and was barely hot after a run. Just think of the BTUs that engine puts out at full throttle.
If you have a radiator, you have a water pump. Just build a tank with a radiator cap, use a thermostat, and you will be fine.
Don
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Look for an intercooler's Ice/cooler can -- fill with water and ice and let it circulate thru you engine -- -- no need to have a radiator inside of it
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So, you guys are suggesting an un-pressurized tank?
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No, put a radiator cap on it, pick a cap under the bursting strength of your tank. :| A simple aluminum tank that holds about a couple gallons of water should work for your use. Might even get by with less, look at the spot you plan for the tank and build it that size. We use a 5 gallon tank for our car, thermostat and the engines pump. Figuring that the water starts close to 100F we see the sine wave of the thermostat opening and closing through most of the run, the last 1/2 mile the thermostat is open and the Max temp we have seen is 220... we leave the motor running until the car comes to a stop on the return road.
Work your way up, if you think the water is too hot at the end of the run, put ice in it and start with cooler water.
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No, put a radiator cap on it, pick a cap under the bursting strength of your tank.
OK, thats what I was concerned about. Im clear on it now. Thanks everyone.
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We are having trouble deciding whether we should run a radiator in our D class lakester. It's been suggested that we just run a water tank. Is there a formula I can use to calculate temps? Any thoughts or suggestions? I started a thread about this question earlier tonight. If it was inappropriate for me to re-post my question, please let me know and I will promptly take appropriate action by removing the post. Thanks.
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We run a not-full 18-gallon tank in a roadster with both C and D gas engines. It puts some weight in the rear where we need it. We run the long course at Bonneville and have never seen over 195ยบ in the motor. (Probably would have had more horsepower with a higher temp -- easily done by restricting the flow -- or even using a themostat somewhere(!).
Here is the maintenance cost on our low-cost-to-build system after 5 records and 12 years --$0.
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http://www.avsontheweb.com/1-gallon-aluminum-tank-with-4-ports-silver-free-drain-port-fitting/
Think this will work?
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Mike, you got all of the best advice above. You can't go wrong. :cheers:
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We like to put the hot in the top and pull cool out of the bottom.... how you going to mount that?
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We like to put the hot in the top and pull cool out of the bottom.... how you going to mount that?
I'd have to weld a cap spout on and replace the 1/2" bungs with larger ones anyhow so I could mount any way I needed it. What do you think of the tank itself? Certainly like the weight and capacity. Pressure shouldn't be a problem. It's tiny enough to fit several places.
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I have used radiators in ice water and it worked great. Last year I changed to a plate exchanger. It was more compact, and I was able to add a thermostat. I fill the tail with ice and water before a run. The little pump circulates the cold water through the exchanger. The thermostat opens at 107 degrees. I never like to see more than 140 at the end of a run. Keep in mind a hot two stroke loses a lot of power. Don't run it as hot as a foul/four stroke.:D
(http://img.photobucket.com/albums/v283/superr5/race%20bike/2014-07-03%2021.20.27_zpsp6qnqmcx.jpg) (http://smg.photobucket.com/user/superr5/media/race%20bike/2014-07-03%2021.20.27_zpsp6qnqmcx.jpg.html)
I machined some housings for a thermostat that goes to a snowmobile IIRC.
Also I run 500cc, so for your 100cc engine, you could really make a nice regulating coolant system in a compact space.
(http://img.photobucket.com/albums/v283/superr5/race%20bike/thermostat_zpsvbnastzs.jpg) (http://smg.photobucket.com/user/superr5/media/race%20bike/thermostat_zpsvbnastzs.jpg.html)
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I think it is a great tank with plenty of potential for your use after you mod it to your needs.
Keep up the good work :cheers:
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I think it is a great tank with plenty of potential for your use after you mod it to your needs.
Keep up the good work :cheers:
I can't get inside the bike for a look-see but I'm thinking it might fit vertically between the front frame downtubes. That would be ideal for your "hot into the top - cold out of the bottom" tip.
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On our car, we put the hot in the bottom, but into a stand pipe that delivers it to the top. The supposedly cool comes out the bottom, but after 5 miles I'm sure there is some intermixing.
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On our car, we put the hot in the bottom, but into a stand pipe that delivers it to the top. The supposedly cool comes out the bottom, but after 5 miles I'm sure there is some intermixing.
Why use the stand pipe?
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Easier to plumb that way -- with both coming out the bottom.