In article ,
Roger Mills wrote:
It's an oft quoted figure for the masses. Same as BHP is all important to
bar room mechanics. But it doesn't tell the full story. Only that car
makers tend to produce roughly similar engines.

A colleague of mine at Rover studied this is some detail, and plotted a
graph of 0 - 30 times (admittedly not 0 - 60) against power to weight
ratio for a wide range of vehicles. He found a very strong correlation.

Well yes. Since most makers aim for the same sort of engine output curve.

But I'll ask you a question. Take a high revving bike engine with a
very high specific BHP per litre and put it up against a lightly
stressed but torquey V8 etc in vehicles with the same power to weight
ratio. Which one will accelerate better?


Why compare a bike engine with V8 car engine?

Because you've singled out power to weight as some sort of benchmark. And
it would be easy enough to find a small capacity high revving bike engine
with the same sort of peak BHP as a lazy V8. Put them in vehicles so the
power to weight ratio is the same, and see which one accelerates faster.
It will be the one with the flatter torque curve.

--
*How do they get the deer to cross at that yellow road sign?

Dave Plowman London SW
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