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Old 05-13-2009, 06:07 PM   #36 (permalink)
binarycortex
LurkoModding Ecker
 
Join Date: Sep 2008
Location: Da Desert
Posts: 51

new beetle - '98 Volkswagen Beetle GLS
90 day: 32.98 mpg (US)
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Quote:
Originally Posted by MechEngVT View Post
I have read that BMW instructs drivers to accelerate at 75% engine load and shift when the engine's mean piston speed reaches 1200-1500 feet per minute. Mean piston speed is a function of engine stroke and RPM.

Vp=RPM*S/6

Vp= mean piston speed
RPM= engine speed
S= engine stroke length, inches
I find this very interesting. I have heard that you engine is at its most efficient when it is producing the most torque. The 2.0L New Beetle's peak torque is at 2600 rpm. Using the above equation 1200-1500fpm is roughly at 2000-2600rpm. The actual numbers are 1216, and 1581fps for 2000 and 2600rpm respectively.
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