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Dyno - IN@RR
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Dyno - IN@RR
Might be a stupid question, but here goes. What does the numbers IN@RR mean on the dyno? Does it have any effect on the final outcome (and how)?
Im thinking the RR relates to ramp rate
From someone else
"The ramp rate, adjusts the resistance the dyno places on the car's wheels, so the speed increase is controlled, and hopefully linear. e.g. with a RR of 15, the dyno will try and limit the cars acceleration to 15km/h per second. The amount of resistance (retardation) required to keep the acceleration in check is used to figure out the power being made."
If you go to fast then you perhaps get less data
too slow and things are getting hotter
From someone else
"The ramp rate, adjusts the resistance the dyno places on the car's wheels, so the speed increase is controlled, and hopefully linear. e.g. with a RR of 15, the dyno will try and limit the cars acceleration to 15km/h per second. The amount of resistance (retardation) required to keep the acceleration in check is used to figure out the power being made."
If you go to fast then you perhaps get less data
too slow and things are getting hotter
so ramp rate doesn't refer to an actual ramp or the angle
its the rate at which the car accelerates. or "ramps" up in speed.
so a rr of 15 means the dyno is going to only let the car accelerate at 15km/hr/s. it will then measure how much load it has to put on the car to keep that steady acceleration. A powerful car is gonna want to accelerate faster than 15km/h/s so the dyno will read more power.
Whether the readings are high/low in theory shouldn't change since the RR is part of the equation but the bigger the gap then more faith your putting into a factor which probably gets skewed
The closer you can get RR inline with the actual cars on road acceleration the less chance the factors will get skewed.
Best practice seems to be to set the RR based on an actual road test of acceleration.
As long as you keep using the same dyno and set up, i wouldn't worry about it. a 50kw gain on one dyno might be a 30kw gain on another but on the track it runs just as fast. I use some software to work out a HP curve based on RPM change over time and it can be tweaked to say whatever i want it to. But as long as i keep the same factors i can see the relative increase or decrease of my tuning
its the rate at which the car accelerates. or "ramps" up in speed.
so a rr of 15 means the dyno is going to only let the car accelerate at 15km/hr/s. it will then measure how much load it has to put on the car to keep that steady acceleration. A powerful car is gonna want to accelerate faster than 15km/h/s so the dyno will read more power.
Whether the readings are high/low in theory shouldn't change since the RR is part of the equation but the bigger the gap then more faith your putting into a factor which probably gets skewed
The closer you can get RR inline with the actual cars on road acceleration the less chance the factors will get skewed.
Best practice seems to be to set the RR based on an actual road test of acceleration.
As long as you keep using the same dyno and set up, i wouldn't worry about it. a 50kw gain on one dyno might be a 30kw gain on another but on the track it runs just as fast. I use some software to work out a HP curve based on RPM change over time and it can be tweaked to say whatever i want it to. But as long as i keep the same factors i can see the relative increase or decrease of my tuning
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