Keeping The Machine Cool

Nov. 01, 2005 By ORC STAFF
Keeping The Machine Cool

Consider that you?ll run your sled to get to the staging lane, down the racetrack and back to the pit area. Total running time? 5 minutes, if that. So how hot does it get? Through the hottest days of July with temperatures in mid 90s my sled never cracked 210?F. Typically the water gets up to 160-180?F. The most critical time for temperature concerns is after the race. The water stops circulating when you turn off the engine. Then it heat soaks: the water temperature will go up as it soaks up the heat from the engine. When the engine and water temperatures have stabilized at their peak, then it will start to cool down. So you should have a cool down cart. Generally, the cool cart consists of:

  • A cooler or other suitable container to hold 5 gallons of water.
  • A pump to circulate the water. A 12v bilge pump works nicely.
  • 10 ft of ?" hose, either garden hose or flexible plastic hose from a hardware store. Be sure to use a hose that is suitable for hot water. Some types of hardware store plastic hose will not stand up to 200? water.
  • Quick connect fittings for the hoses on the cool cart and coolant hose on your sled.
  • A 12v battery to power the pump.
  • A cart or wagon to put it all in so you can move it around the pits easily.

 

The photos below show a typical cool cart.

The one I use is shown in the following picture:

I built it all in my sons Little Red Wagon. It fits neatly inside the snowmobile trailer. Generally you fill the cooler with water and circulate it through the sled to cool it. After the sled cools down (usually the water stabilizes at 80-90?F) you have an insulated cooler full of hot water. To cool the water in the cooler down most people put bags of ice in it.

At ESTA Safety Park where I race they have water spigots in the pit area. I fill my cart with water from the spigot (usually about 50?F) just prior to racing. After it?s been used to cool the sled I drain the water out of tank and refill it. Works good, saves a few bucks on buying ice for the cool cart every weekend.

Connecting the cart to your sled is pretty straightforward. The quickest and easiest way to connect is to tap into the coolant line that goes between the coolers under the tunnel (at least on a Ski-Doo).

The quick connect couplings are available at any hardware store. They fit ?" hose. Make sure to use the kind with check valves so you don?t get blasted with 200? water when you disconnect them. After a pass down the track you disconnect the lines on the sled, connect them to the cool cart and turn on the pump. It will circulate water through the coolers, engine and coolcart. Some people put the fittings under the cowl. This makes a nice clean look from the outside of the sled, no unsightly hoses running around. It?s your choice where you want to connect the lines. Keep in mind that most of the coolant lines on the engine are 1" lines. The fittings you get from a hardware store are made for ?" hose. Also, the garden hose connectors have an actual outlet opening of only 3/8" diameter in the connector. On a stock machine the restriction caused by the 3/8" opening may not be of concern. However, if you are scratching for every bit of performance you can get, this restrictive coupling may be loading the impeller on the crankshaft at high RPM. I recently replaced my garden hose fittings with 1" full flow hydraulic couplings ($$!!)

I was not able to discern any change in ET. But it was just one of the many little things that scrub of small amounts of power.

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