Bogus Dyno #'s?
#1
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Bogus Dyno #'s?
I'm just wondering about some of the dyno sheets I have seen floating around.
From what I understand about HP is that it is basically calculated by your torque. The magic # being 5252. HP = Torque x RPM ÷ 5252. Using this formula it is imposable to have more torque above 5252RPM's. Ever notice that on a Dyno plot the HP and Torque always cross at 5252RPM's? At least what on what I would call a real Dyno plot.
This brings me to my question... What are these guys doing to get these weird Dyno plots that do not adhere to this rule? I've seen them have more HP than Torque below 5252RPM's and more Torque than HP above 5252RPM's. This leads me to believe that they are trying to estimate Flywheel HP from a chassis Dyno or they are trying to estimate Wheel HP from an engine stand style Dyno.
Either that or I'm just plain stupid.
Would anyone like to enlighten me on this subject?
[Modified by TrueNorthStar, 8:17 AM 1/27/2003]
[Modified by TrueNorthStar, 8:17 AM 1/27/2003]
From what I understand about HP is that it is basically calculated by your torque. The magic # being 5252. HP = Torque x RPM ÷ 5252. Using this formula it is imposable to have more torque above 5252RPM's. Ever notice that on a Dyno plot the HP and Torque always cross at 5252RPM's? At least what on what I would call a real Dyno plot.
This brings me to my question... What are these guys doing to get these weird Dyno plots that do not adhere to this rule? I've seen them have more HP than Torque below 5252RPM's and more Torque than HP above 5252RPM's. This leads me to believe that they are trying to estimate Flywheel HP from a chassis Dyno or they are trying to estimate Wheel HP from an engine stand style Dyno.
Either that or I'm just plain stupid.
Would anyone like to enlighten me on this subject?
[Modified by TrueNorthStar, 8:17 AM 1/27/2003]
[Modified by TrueNorthStar, 8:17 AM 1/27/2003]
#2
Re: Bogus Dyno #'s? (TrueNorthStar)
examples? pictures/urls?
did you check each axis to see if they used diff values increments for torque/HP? a lot of dynos I see use torque on the right with smaller value increments, and HP on the left. So because they arent both correlated with the same Y-axis for values, they wont cross at 5252 rpms.
did you check each axis to see if they used diff values increments for torque/HP? a lot of dynos I see use torque on the right with smaller value increments, and HP on the left. So because they arent both correlated with the same Y-axis for values, they wont cross at 5252 rpms.
#3
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Re: Bogus Dyno #'s? (TrueNorthStar)
Some dynos use different scales for HP and torque. If, say, torque has an exaggerated scale compared to HP, torque will always appear to be higher.
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