Disclaimer - I think this is my first post here so......
I started a build (that 7 years later is still not done
- but it has been a massive amount of work) and got a copy of dynomation 5 to help.....and I like it over all. I've modeled about a dozen engines for friends, about 1/2 of which have hit the dyno and the sim has hit the final numbers within about 2%. Not bad....but there is definitely an art to getting good numbers out of it.
The way I use it is to to a quick and dirty sim using the FE model to base line everything. On some engines, like the 70s. 80s ferraris I play with, the final number I trust is from the FE model because the wave model simply doesn't work well on them and comes up with a pretty low number. It does get changes right so it helps with the tuning stuff and once I rework the heads the wave model does get close. The best I can tell the intake system/shape just doesn't match the assumptions the wave model is based on well enough.
As some one else said it seems to want the bare head flow number and then applies a correction for the type of intake fitted. The ITB selection seems to pretty much use the flow data as-is and I have tried using the full intake system data then selecting ITB and it seems to be about right but I've only seen dyno data on a couple so....maybe yes maybe no I guess.
Also as already pointed out, the way it does the headers seems a bit sketchy and I really don't trust it for that work. It has not way to account for firing order, tri-Y designs, cross or x pipes, it just seems to assume only the pulses from the active cylinder matter. If custom headers are in the plan I just call Burns and have them design something then plug that design into dynomation and don't touch it. I have pipe max too and it's helpful but the couple designs Burns has done for me have worked better in dynomation than what pipe max spit out.
The last think I go by is whether the wave prediction in soundly beating the FE prediction of not. The FE is a simple pumping model so the "tuned" wave model should beat it and if it's not I assume the tuning still needs help. Normally when I'm done virtual tuning the wave is a solid 10% above the FE. On my never ending project engine the FE says 777, the wave says 949, so the wave is up 22%. The Hybrid spits out 897 but the curve look just flat wrong up near the hp peak.....the way it combined the curves doesn't seem to handle big differences in the FE/Wave numbers very well do I don't use it.
A buddy of mine has a H-D shop....dynomation gets his engines pretty wrong. The FE is WAY low and the wave needs the cams in at 110/110 to get close to whatever his actual cam timing makes so the cam timing function is useless on his engines. Another buddy who does a lot of US pushrod car engines gave me the heads up on the "just set the cams to 110/110 then fix them on the dyno" answer. Thats a fine answer when you have 2 headhead cams per bank and can set them anyway you please on the dyno.....but not so fine an answer when you have to move intake and exhaust together or have a new cam ground. No idea why...pushrod flex is all I can think but I have no real idea.
Another heads up is actual measured cam profiles are the preferred way to input cam options. The 10-point system dynomation uses to estimate sort of works for a baseline, but the output of measured and estimated can be quite different. On my engine the measured cam data get me the 949 number, if I click the "convert to 10 point" buttons the output drops to 907, nearly a 5% difference in the peak and the shapes. If I roll the lobe centers around I can get back to 925....but then whats the right baseline 102/110 the measured cam wants or the 111/115 the 10pnt version wants....hmmmmm.
I've found it's quite addicting and has cost me years trying to actually build the parts dynomation likes.
