View single post by Mark Rosenbaum
 Posted: 04-02-2005 11:46 pm
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Mark Rosenbaum

Joined: 03-12-2005
Location: Kingman, Arizona USA
Posts: 532
I recall seeing, 40 years ago, dragsters starting a run with 5 or 10 gallons of ice water as coolant.  By the end of their run a few seconds later, that water was boiling.  Of course the dragsters had no real means of transferring coolant heat into the environment.

Any practical cooling system must dump enough heat so that the car doesn't overheat for the duration of its use.  This is where the presence of additional coolant and oil provide their benefit: they add mass that can absorb more heat before the engine as a whole overheats. An ideal cooling system would be able to dump all the heat produced by the engine.  The extra size, weight, and frontal area requirements of such systems are usually major drawbacks.  However, a lot races have been won by slow heavy cars that kept running long after their faster, quicker competition broke down.  In most cases, it ends up being a judgement call.

If the rules under which you're racing allow, you can see a significant improvement over the stock cooling system without much effort.  Basically, this means making certain that as much air as possible flows smoothly through the oil cooler and radiator when the car is at speed.  This means (a) a front spoiler to increase the effective area of the air inlet, (b) smoothing the sheet metal and transitions in front of the radiator -- think of this as 'porting' the radiator inlet, (c) sealing all unused openings in the radiator bulkhead, (d) sealing the full width of the gap between the top of the radiator bulkhead and the underside of the hood, and (e) ensuring that the heated air can exit the engine compartment as easily as possible -- in the case of the JH, this will most likely be via the gap between the back of the hood and the windshield.  Increasing the air flow over the headers will also be of benefit (though in a LHD car, the driver may cook).

You can try placing the heater core in a container of ice and get rid of a fair amount of additional heat as the ice first liquefies, then boils away.  If the ice container is sealed save for a single vent, and you put a rocket nozzle on the vent, you gain a tiny bit of thrust that may help a little.  No, I'm not joking here -- it's been done, though I don't currently recall when or where. 

One trick to improve airflow across sheet metal is to replace any protruding hardware with flathead screws.  Another is to use a fan to redirect air from rough areas to smoother ones -- technically, the fan itself provides little or no cooling.

IMHO, with a bit of experimenting you should come up with all sorts of things that comply with your racing rules and which help.  And if ten small improvements equal one big one, it's usually better to go with the small ones -- you'll lose less of the benefit when one quits in mid-race.