This chart combines the first study data, transitional data, and second study data for
direct comparison
Percent vacuum sweep is directly proportional to BMEP, in turn proportional to percent
of available torque
Torque required is
constant at constant drag, so if the percentage is lower, there is more
available power
Lower percent torque to cruise means higher mileage and higher efficiency
Predominant morning low temperature turned out to be a major correlating variable
The second study config (5) requires somewhat less torque to cruise in cold weather than the
first study config (4)
Both appear to require the same torque in warmer weather, so the slope of the trend with config
5 is less
That means config 5 is less sensitive to cold weather effects, and the revised preheat
modification was a success
The transitional config 4.5 is on the high side of the config 5 trend, and just above config 4,
consistent with the minor effects of softer tire inflation and the older preheat design
