Originally Posted by Christian and Beccy

The figures are pretty much scrap if the RPM reading was wrong. Next time you go, quiz the guy over what he uses to read RPM. If they could be bothered, they could use a pick-up that goes onto a plug-lead. It's hardly difficult, just some would rather wing-it and use the tacho.

If you want a good reliable figure, find someone with a Dyno Dynamics Dyno.