I'm curious if anyone here has compared Desktop Dyno type software predictions with real dyno pulls.  They advertise the result to be within 5%.


Lawrenceville, GA

When I built my 351W stroker, my Dyno 2000 sheet showed roughly 615 flywheel hp.  Now, I used my actual flowsheet from my head porter, plus actual compression ratio figures, and actual camshaft figures taken from my cam card.  All of these items were input and figured many times, before I ever purchased a single part.  I never actually had it on a dyno, except for the 1/4 mile dyno.  Using the weight of the car with me in it, and the info from my time slip, I was able to figure that my car made close to 510 at the rear wheels.  That number was a little off on the ET(tire spin from worn out slicks), but the MPH was the main concern.  So taking into account drivetrain losses, friction, etc, the flywheel hp should have been around 590 or so, where Dyno 2000 showed 615...pretty close, or close enough to use before spending a load on wrong parts anyway...

James Potter
`57 Fords International



`57 Custom Tudor

`57 Fords International National Director

Pass Christian, MS (near Gulfport/Biloxi)

This is why I'm curious.  My friend just got Dynosim 2008.  It the version a step down from pro.  We put all the info we could about my engine and this is the prediction:

So, if it proves to be within the 5% they advertise, this makes me very happy.  That's 380 ft/lbs @4000 and 356hp @5500.  I think the low end torque is a little optimistic.  It sure doesn't feel like 276 ftlbs @ 1500.

Lawrenceville, GA

The thing is, all figures have to be realistic.  If you use the prefab provided airflow figures it will be off pretty bad.  If you have had your heads ported and flowed, and have the flowsheet, you can input that in your program and it will be much more accurate, to the lower side usually.  The flow figures for something like wedge head, stock ports, stock valves, will be pretty high flow numbers.  Remember that most of these softwares are based on small block chevs as that is what most people fool with.  The Dyno Sim program I think is the newest version of Dyno2000, as two companies merged, and the respective softwares were obsoleted as they made the new version.  I also noticed that the price was significantly more for the newer software than what they used to sell.

At any rate, just be sure that you input as much real world data in to get the most accurate output.  You can custom tailor airflow data for the heads, camshaft figures, and combustion chamber/cylinder volumes, so the closer you get to reality on these items, the closer your data will be when you output.

James Potter
`57 Fords International



`57 Custom Tudor

`57 Fords International National Director

Pass Christian, MS (near Gulfport/Biloxi)

That's the cool thing. Every bit of it is based on real figures. We input a chart of the flow up to .500 lift in .050 increments. I built the engine so I have almost every dimension, clearance, etc. written down. The version of the program he has doesn't get detailed enough to use all of the data I have on the build of the engine.

I'll get it on a chassis dyno one of these days.



Lawrenceville, GA

That is cool...If you're making 330-340 that is great...Now plug on a pair of T3s and let it eat...

James Potter
`57 Fords International



`57 Custom Tudor

`57 Fords International National Director

Pass Christian, MS (near Gulfport/Biloxi)