Is DD2000 accurate enough to project the rpm at which the power peaks occur? Up to how much error has anyone noticed?

I am trying to see how different cams might affect an engine build.

 

Has anyone ever checked this out?

 

i made a zz4 engine on the program and it peaked pretty much in the same area as what the catalog says.

 

My old race engine peaked roughly where DD predicted it would. I think that's why I'm afraid with the new engine (once it's back together). DD predicts it should peak at 7500 rpm when I normally shift at 7000.

 

I think that finding peak power (and profile) is one thing that Desktop Dyno can do given bore, stroke, cam specs, and flow rates. It may not be right on as far as power because there are a lot more things that affect that which you can't fully enter reliably.

 

The model starts to fall apart in a hurry past the peak towards redline where it can't predict things like valve float, etc.

 

It assumes everything mechanical is working the way it's supposed to.

It can't predict what ignition timing works best. Something simple like having your timing at 34* total when the engine wants 38* total will decrease the amount of HP produced.
It can't predict the best carb setup. Jets, squirters, pump cams, etc.
It can't predict spark plug gap or temperature range to use.

There are still a lot of variables in a real engine that just can't be calculated with software. All these little things can change hp anywhere from 10 - 100 if not adjusted properly.

DD assumes everything is set to 100% efficiency.

You could build an impossible engine that spins to 50,000 rpm and DD wouldn't know the difference because it assumes mechanically that it's possible. Even having a high HP engine we all know it should have forged pistons but if you put cast pistons into it, would it still be a high hp engine? Well maybe for a short while.