i think theres a set resistance on the roller and it measures out how fast it spins up the roller combined with engine speed,(maybe throttle position aswell on some bikes, n cars) and how much torque is exerted through the roller, then some wizardry happens then it works out the bhp,i sopose they have it so the computer takes away a percentage of resistance to compensate for the drive train drag IE on a bike it would just be the chain n gearbox that adds drag, on cars could be a few things gearbox, differentials, prop, all add weight that the engine has to spin up, n the computer can take away all that roughly to work out bhp n torque at the crank aswell?
A 'brake' dynamometer applies variable load on the Prime Mover (PM) and measures the PM's ability to move or hold the RPM as related to the "braking force" applied. It is usually connected to a computer that records applied braking torque and calculates engine power output based on information from a "load cell" or "strain gauge" and a speed sensor.
An 'inertia' dynamometer provides a fixed inertial mass load, calculates the power required to accelerate that fixed and known mass, and uses a computer to record RPM and acceleration rate to calculate torque. The engine is generally tested from somewhat above idle to its maximum RPM and the output is measured and plotted on a graph.
A 'motoring' dynamometer provides the features of a brake dyne system, but in addition, can "power" (usually with an AC or DC motor) the Prime Mover (PM) and allow testing of very small power outputs (for example, duplicating speeds and loads that are experienced when operating a vehicle traveling downhill or during on/off throttle operations).
Either way, did the guy thrash the shîte out of it? Were you worried at all?
Nothing to worry about, the guys a races in southern England 2 stroke gp, or summit like that.... He know his onions. Still haven't scanned my results yet. Will do today at some point
i've had one done before, it's not that bad, it only seems savage because you're on a "rolling road" and not actual tarmac, or w/e you ride on, and usually they'll put the bike in 2nd, 3rd, or 4th and just max out the revs for a moment then drop off and go back up. plus the rooms they're usually in are small, compact and tinny so it does sound a lot worse than what it really is
