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- Jun 30, 2012
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- 13,277
I am very ignorant about how dynos are constructed. Last night a friend rang me and discussed the activities of his mate in Queensland. The guy has a Kawasaki engined bike which he uses for speed records. He was looking for someone with decent dyno skills and found someone in Brisbane who works on nitro/methanol fuelled stuff. On changing from petrol to methanol, and playing around, he found a slight increase in BHP, but a massive increase in torque. He then found the bike was much quicker up through the gears, so the top speed was also higher. My question is about how torque is measured on most dynos, and how it is related to engine revs /throttle opening. I don't know how the energy created by the motor is dispersed on most dynos, and from watching the videos of Kenny Cummins, it looks as though the power readings are taken off the roller which is driven by the rear wheel of the bike. Years ago I was in charge of rocket motor firings. To measure the thrust we used to hang the motors on gimbals made from strong sheet metal strips and direct the force through a computer monitored load cell. ( pants-filling stuff ! ) I suggest that what is important with a bike motor is the forward thrust of the bike in relation to engine revs. Getting a digitised rev counter and load cell with the range and which is sensitive enough to handle what comes off the front of a bike, could be a problem . We used to cut our own crystals and glue them to a substrate, then calibrate them with a dead weight tester. It might be possible to have the bike push against a long lever ? You would be looking for gains in midrange power. How sensitive and reproducible are modern dynos in measuring torque from the roller ?
Rohan, my friend made the same comment as yourself about moving into the modern era and using dynos to measure motor output. I can see merit in the idea, however the practicalities might present a problem. It is easy to be deceived by numbers .
http://www.youtube.com/watch?v=3IWFVyQm29I
Rohan, my friend made the same comment as yourself about moving into the modern era and using dynos to measure motor output. I can see merit in the idea, however the practicalities might present a problem. It is easy to be deceived by numbers .
http://www.youtube.com/watch?v=3IWFVyQm29I