How much rwhp to get 500 crank hp?
05-12-2011, 05:12 PM
#22
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I just did the calculations and in a vacuum w/air to feed the motor I am making 1900+ RWHP! Keep in mind I'm using Slick 50 that removes all internal resistances. It's also a weightless environment so the reciprocating mass and rolling resistances can be taken out of the equation as well.
05-12-2011, 06:43 PM
#23
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Another thing I wanted to say was that based on working in an industry where big gears are used to transmit power to machinery, we typically estimate hp loss based on percentage of total hp made by the driving equipment, or the max hp load expected to be seen by the equipment.
A typical estimation is 2% of driver rated power. A 5000 hp electric motor driving through a typical speed increasing pinion/bull gear type gear setup we'd typically expect close to 100 hp loss. Most of the time the actual quoted loss is between 1 and 2% loss every time no matter what rpm or power level, whether its 1000 hp or 40,000 hp. The actual required load through the gears is a big factor in the loss, but rpms also has effect since there are bearing friction losses.
In the variable speed gear equipment, which are basically torque converters with a gear setup, the losses change per rpm and load for each operating point. Same internals but the losses change based on different input powers, so its a big part percentage and some constant losses based on frictional losses per each constant RPM.
Transmission and rear end would be same idea here, but there are alot more losses due to multiple gears and frictional losses. Converters and clutches, transmission gear arrangement and then rear end gears and the bearings the shafts ride on.
A typical estimation is 2% of driver rated power. A 5000 hp electric motor driving through a typical speed increasing pinion/bull gear type gear setup we'd typically expect close to 100 hp loss. Most of the time the actual quoted loss is between 1 and 2% loss every time no matter what rpm or power level, whether its 1000 hp or 40,000 hp. The actual required load through the gears is a big factor in the loss, but rpms also has effect since there are bearing friction losses.
In the variable speed gear equipment, which are basically torque converters with a gear setup, the losses change per rpm and load for each operating point. Same internals but the losses change based on different input powers, so its a big part percentage and some constant losses based on frictional losses per each constant RPM.
Transmission and rear end would be same idea here, but there are alot more losses due to multiple gears and frictional losses. Converters and clutches, transmission gear arrangement and then rear end gears and the bearings the shafts ride on.
01-30-2022, 06:26 AM
#25
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Horsepower calculator https://www.mk5cortinaestate.co.uk/calculator4.php
01-30-2022, 10:49 AM
#26
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Here is a reasonably accurate online calculator that can attempt to provide crank and/or wheel horsepower based on some know factors you provide, such as stock crank horsepower:
https://www.mk5cortinaestate.co.uk/calculator4.php
https://www.mk5cortinaestate.co.uk/calculator4.php
11yr old thread 😂
