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#16 | |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,517
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Quote:
Maybe you mean that the two main things that affect hp output (rpm and throttle opening) result in less than, or peak hp for the engine. Well, YES. Peak horsepower on an rpm curve is the standard output of the DYNO. But peak hp for the engine actually does not change. For instance, you can obtain higher torque to climb a steep hill by shifting to a low gear. Seems like higher hp, but the same amount of work is being done...I mean, The overall kWatts of power is the same as pushing the bike through the air at 75mph. That's horse power. Torque is a MECHANICAL ADVANTAGE, but you expend the same amount of kW (hp). Got to admit, your argument sounds like AI generated. No real intuition.
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-2022 5 speed Templar X Orange, OEM 51T rear sprocket, 14T front sprocket -NOS 2020 KTM 250SX (2-stroke motocross), less than 10 hours on it |
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#17 | |
Join Date: Aug 2013
Posts: 232
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Quote:
There is a point where gearing is optimized, and you can't get past. In most cases, ho to the wheel is lower than in that optimized state. It's when the engine peak output and the load balances one another out where the engine does no longer accelerate, or rpm no longer increases. On a dyno, rpm increases past peak HP, because the load isn't realistic. Hence you'll get different HP ratings from dynos with heavier or lighter rollers. All the math on this forum doesn't take that into consideration. It only takes into consideration when engine output is measured on a single load (single dyno). Not on a variable load, which is what happens when you accelerate, and wind resistance becomes higher at higher speeds, and prevents the bike to go faster. |
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#18 |
Join Date: Feb 2021
Location: Kansas City
Posts: 2,517
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Can't interpret your post. You really seem to think that the optimum output of an engine in kW or hp changes. Bottom line is in fact that the engine can't make more.
As I stated, "Torque is a MECHANICAL ADVANTAGE, but you expend the same amount of kW (hp)". Just because a geared down engine can lift a 3 ton pallette doesn't mean that the 20hp engine in the forklift makes more than 20hp. You are just not thinking. It is still 20 hp. Work includes a distance meaurement and time factor. Maybe you are missing this? 70mph pushing through the wind (more than a mile per minute, where wind provides constant friction), or lifting a truck at 3 inches per minute, against gravity. It is still 20 hp (14.914 kW).
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-2022 5 speed Templar X Orange, OEM 51T rear sprocket, 14T front sprocket -NOS 2020 KTM 250SX (2-stroke motocross), less than 10 hours on it |
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#19 | |
Join Date: Aug 2013
Posts: 232
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Quote:
The rated output or the actual output? And your example shows lifting a pallet at a fixed speed (thus fixed load), vs wind resistance, which can be both variable and fixed. The point I'm trying to make is in one example, the engine is easily overcoming the load lifting, but lifts at a fixed speed. In the other, the wind resistance and engine output will balance to a point where the engine won't be able to overcome the wind anymore. It would make sense if the same engine can lift the weight at different speeds. The work performed with low gears, will put out a low power output; say 10HP; despite the engine being rated at 20hp,because the engine load is 50%. You take that engine to the calibrated factory dyno, and it'll still show 20hp. You change the load on that dyno, is the same as advancing the timing a bit, and the engine's efficiency rating goes up. If the engine runs more efficiently, it's HP output can exceed it's factory rated output. And there are lots of reasons why an engine can exceed it's rated output, one of them is increasing the load to match maximum load with maximum engine output, where both forces balance one another out. The factory never tests and rates engines like this, but if you load an engine like that, the output can most certainly exceed it's rated output. You have no difficulty understanding that nos, or forced induction can increase HP, no? Well, in a way, increasing the load can increase the efficiency; resulting in a higher than rated performing engine. |
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Tags |
orion, rps, rps hawk 250, titan, x-pro |
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