Brake Mean Effective Pressure, BMEP, What does it mean?
Because I'm a 2 stroke guy I will be focused on 2 strokes and specifically on the KX500.
Put simply, BMEP is a measurement of the average Pressure exerted on the piston.
Here is a simple formula.
BMEP = 150.8 x Torque in ft/lb / CID
If you know the variables, just plug them in and run the math.
But you need the variables.
I've done a lot of dyno work testing various pipes and reeds so I will use those numbers for examples.
Unfortunately, my numbers are all measured at the rear wheel and not at the crank so I cant filter out the parasitic loss we get through the drive train
Here is one sites claim for KX500 output
Max Power 66 hp / @ 7000 rpm
Max Torque 48.4 lb-ft / @ 6000 rpm
On a fresh KX500 2001 KX500 I measured
Max Power 53.11 hp @ 6520 rpm
Max Torque 44.23 lb-ft / @ 6140 rpm
Brake Mean Effective Pressure, BMEP, What does it mean?
- Sandblaster
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Brake Mean Effective Pressure, BMEP, What does it mean?
If bikes are for kids I'll never grow up.
- Sandblaster
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Re: Brake Mean Effective Pressure, BMEP, What does it mean?
Lets plug in the claimed numbers to the formula
BMEP = 150.8 x Torque in ft/lb / CID
BMEP = 150.8 x 48.4 ft/lb divided by 30.5119 CID
BMEP = 7,298.72 divided by 30.5119
BMEP = 239.20 PSI
BMEP = 150.8 x Torque in ft/lb / CID
BMEP = 150.8 x 48.4 ft/lb divided by 30.5119 CID
BMEP = 7,298.72 divided by 30.5119
BMEP = 239.20 PSI
If bikes are for kids I'll never grow up.
- Sandblaster
- Posts: 6313
- Joined: Thu Jun 07, 2012 3:50 pm
- Location: Eugene, OR
- Contact:
Re: Brake Mean Effective Pressure, BMEP, What does it mean?
Here is my numbers
BMEP = 150.8 x Torque in ft/lb / CID
BMEP = 150.8 x 44.23 ft/lb divided by 30.5119 CID
BMEP = 218.59 PSI
BMEP = 150.8 x Torque in ft/lb / CID
BMEP = 150.8 x 44.23 ft/lb divided by 30.5119 CID
BMEP = 218.59 PSI
If bikes are for kids I'll never grow up.
- Sandblaster
- Posts: 6313
- Joined: Thu Jun 07, 2012 3:50 pm
- Location: Eugene, OR
- Contact:
Re: Brake Mean Effective Pressure, BMEP, What does it mean?
What can we learn?
Kawi measured at the crank and I measure at the rear wheel
But there is more.
Kawi measured at the crank and I measure at the rear wheel
But there is more.
If bikes are for kids I'll never grow up.
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