Quote:
Originally Posted by Frank Lee
No way that dinky plastic pulley on my Ford is meant to transfer 10 hp! I can't even imagine a 5 hp engine working hard to spin the pump at up to 7k, tops.
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You sure? At 7k, 5hp comes from only 5 Nm of torque. Not a lot of torque, but I don't know the load capacity of belts.
mja1, I'm pretty sure people who race/track will tell you that 10hp is a lot. That aside, the whole point is that an engine doesn't need the amount of coolant flow that the stock pump provides, because the stock pump is supposed to provide adequate flow at idle. Load determines in cylinder temperature, not rpm, so increasing rpm of the engine does not mean the cooling requirements drastically increase. The point is that the pump only needs to turn say 1500rpm while you're rolling down the highway.
You do make a good point about the reliability, but we're talking about efficiency here, and the fact is that the pump on your typical car is spinning way too fast, and that an electric pump provides savings even when driven off the alternator. For racers this matters much more since they run the engine at very high rpm where the pump is cavitating and consuming a sizeable amount of power, but if your engine is to not overheat at 1500rpm, then there isn't any reason for your pump to need to turn much faster than that.