Originally Posted by Stu @ M Developments

Thanks,
A dyno is just a tool to measure something. But like a ruler, its only any good if its accurate and, actually far more importantly, REPEATABLE.

The cooling and constant fresh air of the same temperature keeps it repeatable. A good example is a recent BMW M140 we did. Pretty hard to dyno as they have such a strong powerband and the engine bay is so tightly packed that you need good cooling to keep them consistent.... but look how repeatable the dyno is over 6 back to back runs.



The operator fudged the start on one run, but the point is still easy to see. If we tuned that and then saw less (or more) power, we KNOW its a real change.

Some dyno's cant do the same run twice,. let alone six times!