The importance of proper airflow and cooling during Dynamometer Testing

A fan like the one in the picture is the bare minimum that should be used.  Bigger is much better still.  If you can actually stand up in front of it,  and you don't need ear defenders, then really its just not enough.  REALLY!   Its not there just to stop overheating!

I have seen LOTS of dynamometer setups in all kinds of situations.  About 99 percent of them simply do NOT have enough airflow for accurate back to back testing.   They mostly use a pathetic little two foot diameter fan!

A small 2 foot diameter that you can talk over is "ok" for a single "power" run.  It will stop the car or bike actually overheating (most of the time).  But that's not the point!

Dyno testing and setting up race cars and bikes requires controlled conditions. A bike or car that gets "warmer" over say 2 hours testing suffers from heat soak into the transmission, bodywork, engine block, oil, ancillaries etc.  This effects the power produced.

To keep this in check, you really NEED  a wind tunnel with your dynamometer in it.  When you are driving at full power there is normally a lot of cooling air!  Try sitting on a 150mph bike without a helmet on, its "very" windy!   This cools ALL of the vehicle.  Obviously this is impractical, but a fan like the one in the photo, or preferably two with the door behind them open will give the most repeatable results.  

If your Dyno or the place you go to get your car or bike dyno tested does not have at least as good as the photo above then do yourself a favour, go somewhere else!

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