i've always been under the impressions that dynos MEASURE torque, and that they CALCULATE horsepower from this measurement..
so TORQUE is actually MEASURED, and HP is determined w/mathematical equation ... have i been misinformed ??
there are two questions i'd like to get informed answers to..
1. i went to make some dyno pulls today to see the difference with my new tranny/converter setup since my last tranny was slipping badly on the dyno last time...
when i got it all strapped down, the guy asked me where he could hook up his "tach" lead to..(spark plug wire for instance haha).. i told them they needed to hook up an optical to the crank dampr..well their optical was broken and i had no idea where to get a rpm signal w/out tearing a bunch of **** open to get to an injector signal or crank position signal..
he told me """ no problem, we can still dyno it, but we just won't be able to get a torque reading, just HP"""...
how is it that they can dyno it, get a HP reading w/out a tach signal, but they can't get a torque reading w/out tach signal ?? i know that the formula to calculate HP from torque is based on an RPM constant... so question 1 is : why can i get a HP reading w/out knowing the torque, and why is rpm necessary for torque but not HP (isn't torque NEEDED for the formula to work) ??????
question 2 :: since HP is derived from a mathematical formula based on torque (assuming i'm correct in my above thinking) and the dyno does not know whether the vehicle being dyno'd is a gas or diesel (or does it) how come it can correctly give hp/torque relationship ??
let me explain my question.. let's say truck "D" is a turbo diesel that makes 500HP and truck "G" is a turbo gasser that makes 500HP also.
"G" pulls on dyno and makes his 500hp pull.. torque reading is ~500
"D" pulls on and makes his 500hp pull.. torque reading comes back at 1200
or even backward might makes more sense:
"G" makes a pull of 500 FTLBS... hp calculates out to 500
"D" makes a pull of 1200FTLBS... hp calculates ALSO to 500...
how is it possible that it KNOWS to have different HP figures when both trucks made DRASTICALLY DIFFERENT torque..
does the dyno have to be told that the vehicle is diesel vs. gas and does it use a different formulat to calculate the HP accordingly ??
does anyone know the answer to my questions, or am i just trippin ??
so TORQUE is actually MEASURED, and HP is determined w/mathematical equation ... have i been misinformed ??
there are two questions i'd like to get informed answers to..
1. i went to make some dyno pulls today to see the difference with my new tranny/converter setup since my last tranny was slipping badly on the dyno last time...
when i got it all strapped down, the guy asked me where he could hook up his "tach" lead to..(spark plug wire for instance haha).. i told them they needed to hook up an optical to the crank dampr..well their optical was broken and i had no idea where to get a rpm signal w/out tearing a bunch of **** open to get to an injector signal or crank position signal..
he told me """ no problem, we can still dyno it, but we just won't be able to get a torque reading, just HP"""...
how is it that they can dyno it, get a HP reading w/out a tach signal, but they can't get a torque reading w/out tach signal ?? i know that the formula to calculate HP from torque is based on an RPM constant... so question 1 is : why can i get a HP reading w/out knowing the torque, and why is rpm necessary for torque but not HP (isn't torque NEEDED for the formula to work) ??????
question 2 :: since HP is derived from a mathematical formula based on torque (assuming i'm correct in my above thinking) and the dyno does not know whether the vehicle being dyno'd is a gas or diesel (or does it) how come it can correctly give hp/torque relationship ??
let me explain my question.. let's say truck "D" is a turbo diesel that makes 500HP and truck "G" is a turbo gasser that makes 500HP also.
"G" pulls on dyno and makes his 500hp pull.. torque reading is ~500
"D" pulls on and makes his 500hp pull.. torque reading comes back at 1200
or even backward might makes more sense:
"G" makes a pull of 500 FTLBS... hp calculates out to 500
"D" makes a pull of 1200FTLBS... hp calculates ALSO to 500...
how is it possible that it KNOWS to have different HP figures when both trucks made DRASTICALLY DIFFERENT torque..
does the dyno have to be told that the vehicle is diesel vs. gas and does it use a different formulat to calculate the HP accordingly ??
does anyone know the answer to my questions, or am i just trippin ??