Don't know what dyno it was but it was at Gentech Performance here in Canberra. They're a Holden specialist and the local HSV approved workshop.
So what actually is the difference between dynos? roller size? roller grip? friction in the bearings? Because the load cell should be calibrated so all should read the same at the load cell.
The operator can be a big factor in the difference, just the way the car is strapped down will give a different reading and that can be the case when using the same Chassis Dyno.
Difference brands also give different results.
Then throw in factors like barometric and temperature differences at different locations and on different days.
Basically what you want from the dyno is to get a baseline reading before the tune and/or mods then another reading afterwards to show the difference and the change in the power curve.
Different shops are known for 'happy dynos' where they pull bigger numbers than other shops but the reading between the baseline and final isn't necessarily very different or the difference is much wider as the operator has tied down the car to make the tune look better.
Read up on dynos and you'll find just how inaccurate and unreliable they can be and how easy it is to manipulate the readings.
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