these might be here but I would like to know what is the most acurate of both and why.
More clarification would be hlepfull.

Thanks to all in advance

 

A dynojet dyno measures the force of a known object (the roller) to calculate torque using the formula F=MA or force = mass * acceleration. A mustang dyno uses an eddy current brake and a torque lever to measure the torque and is more accurate. Typically, a Dynojet dyno will read higher than a Mustang dyno, or Dyno Dynamics, or Dynapack. Additionally, since the Dynojet dyno cannot control the load, a turbocharged car will not show an accurate boost curve since the turbos aren't loaded properly.

 

Great info thanks

 

Click here for an article that describes the differences between the Dynojet and Mustang dynos. There are issues with the amount of loading on the Dynojets. I found I develop more midrange boost on my 951 on the road than I do on a Dynojet because the dyno doesn't load the car enough while the boost is ramping up.

 

Dynopack is pretty accurate. IMO.