Desk Top Dyno

Sorry, I didn’t get to sit down with my laptop and mess with the flow numbers like requested. Might be tomorrow before I do.

On the topic of port flow numbers and my version of Desktop Dyno 2000, I know it does some extrapolation of things like cam info, so I suspect it does the same with the port flow numbers. I can plug in numbers at certain values but no idea what it does if the valve lift exceeds those numbers or what it uses between them. My guess is that it extends the curve if the lift exceeds the entered numbers. But if the flow numbers end just before the numbers “drop off” ( :D ) I bet it gets it wrong. So, in this case the more info the better and if they include the 0.050 data points even better.

I have the manual for my copy of DD and it talked about the extrapolation of the shape of the cam lobe and how DD is going to give a more accurate result if the advertised numbers are entered. I was going to review the manual again to see if it said anything about the port flow numbers but have done so yet.

On a note about the terminology of “drop off”, I find it funny that in my mind the term was used correctly for port flow numbers that only gained 5 or 6 cfm between points. The increase of cfm “dropped off” at that point. If it had lost flow, then I would have said it “lost flow”. But I am no head porter nor am I an engine builder so not arguing that my terminology is correct, only that it was how I thought about it. :)