Home Forums Tech Talk Engine dynos with programmable sweep rate Reply To: Engine dynos with programmable sweep rate

Chad Harrington

Thank you guys for your sensible advice.  I agree on diminishing returns as we dive deeper into detail, but also want to look at how to maximize the money spent on an engine dyno.  I guess what I what I was hoping was a fast control engine dyno that can add the exponential aero load, without costing too much.  Since it is not rapid transient like track sim or for very powerful engines shooting through low gearing, but rather the opposite and just optimizing for the medium and long straights; such load control should not be difficult to create.  After all we can gear to add most of the aero load after best linear fit, and be very close in a specific range.

James, the data to simulate the load is easy – the straightway acceleration engine speed curves on track and dyno, just have to match closely.  It can be a 2  – 3 try iterative process, starting with calculation of the engine load, which will get close and make a good starting point.   Thanks for the aero numbers… how long ago were they reported?  Is it for current generation bodywork?  I plugged the numbers you provided and got the drag force shown in red.  The dashed line is target additional inertia load I would gear for (artificially tall) on an inertia dyno for best fit in the speed range that matters (most common medium to long straight speed range).