I hope everyone here realizes and knows that Desktop Dyno is not entirely accurate. I run these simulations to help in the component selection process, so that people can build the best motor. It's not supposed to accurately predict the exact horsepower that a motor will produce. It's a simulation, and gives a predicted result. So if I say "desktop dyno says the motor will make 450hp @ 5500rpm" dont go around saying to everybody you have a 450hp motor; you might not.

There are so many variables that Desktop Dyno does not compute, that it cannot be exact in it's calculations. Here are a few examples:
1. Lifter acceleration rate. It has three selections, hydraulic, solid, and roller. Due to the wide variances in camshaft grinds, this is not accurate.
2. Head flow. I have actual flow data for most FE heads, but there is room for error here. The flow data is taken with a specific valve size. While I can change the valve size in the simulation, and Desktop Dyno extrapolates the flow data accordingly, there is no guarantee that it is accurate in doing so.
3. Fuel atomization / detonation. Desktop dyno does not calculate how much fuel is going to drop out of mixture due to velocity, or lack thereof. It also assumes enough octane to avoid pinging and detonation. If either of these conditions are present, the motor will make less power.
4. Quench / combustion chamber dynamics. Desktop dyno does not calculate this. A motor with good tight quench might make more HP than predicted.
5. Exhaust. Very general selections here. Stock manifolds, performance manifolds, small tube headers, large tube headers, and stepped tube race headers, the header selections with or without mufflers. Things like "if I change magnaflows to flowmasters what will I gain" cannot be modeled.
6. Ignition timing. Desktop Dyno assumes the optimum ignition timing, not figuring that it may have been changed to avoid pinging problems. Again, this may reduce power in an actual motor.

So I'd say take these predictions with a rather large grain of salt. What it is good at is comparing different motors, and different components like cams and heads. It does relatively good there. But dont expect a super accurate prediction. Probably within 50hp either way would be a reasonable expectation.

Edit: I think this needs to be stickeyed...

 

Face it you can put the best of everything in something and do a half azz job of setting it up and be ticked it doesnt perform. Take it to a Dyno shop and spend the $$ to get it right, and they will appreciate the "free" 50hp variance all to well. I for one appreciate your helping with a simulation for my ole bucket of bolts, and if you missed by 75 hp hey...

 

Kurt, how low will DD2 go down to and print out?
Dyno Sim starts at 1,500 rpm's.

 

EA3 you have to set all perimeters....Right down to windage. A/F, timing, Vac secs or mechanical..you make your own headers...you use a flow stack..Runner length, Port Volume, Intake and exhaust efficiecy, etc.. I think ? I havent counted them..but on the short side..I think there's about 70 perimiters you have to fill out just to get started...

And I also have the 3.3 version i just got..and it actually has moving graphs and charts that show you everthing as the program is figuring out the Hp and Tq curves..

But I'am still learning to use that one? LOL..I am a Confuser DUMMY!!

RJ

 

Desktop Dyno 2000 goes down to 2000rpm. I wish it went lower.

Russ, how much did that EA3 cost?

 

Kurt they have come way down in price. when I bought my EA3 it was $600 for the Program..But I didnt pay that for it..I gave a friend at the speed shop $100 for it..and Now I have the EA3.3 also...and running it is a very in depth process..It scared me the first time it loaded up!! I think I paid $225 for that one?

There made By Performance Trends....They Have a downloadable web site....I dont have there URL as I'am on the laptop this morning...And I do know Engine Builders that use these for baseline starts for engine builds....exspecialy with new and prototype parts..But of course they dont talk about it..they lead everyone to believe they just did it off the top of there head? Ya right!! LOL

Russ

 

My dynosim starts at 1000rpm, and calculates lifter accel based on the camshaft or you can type in manually.

Kurt, is spot on with the dyno programs. I like the EA programs, but you better be prepared to make some measurements and have all the parts handy. It can take 1 or 2 hours to get one of them done.

Kurt, I think the top program is $300-400.

 

Yeah your right there Bobby!! Thats why I have slowed down doing Desktop sims..for just eveyone...Cause you have to have your **** together! to run them and they take quite a bit of time to do!!

But the advancements in them today as compared to the older ones is like night and day.. The new one's dont take anything for granted... JMO

RJ

 

I just checked the EA3, and it runs down to 500rpm and up to 20,000 rpm...Just for info..But it only does it in blocks of 10..

RJ

 

20.000 rpms??? LOL Cool!!! Can you build a F1 engine sim on that program??? What about top fuel and such?

 

LOL..I dont know about an F1 or an F16..LOL.. but it does desiel too...

I havent even really scratched the surface of what it will do? Never had the need for it? But any Combo you can come up with in your head..Cams that you make up..Headers sizes ..a bunch of stuff that the program wont know until YOU tell it what you have..Then it will tell you if it will or wont work! Even tell you what Octane to run to prevent detonation! LOL.. Oh its a trip alright..LOL

RJ

 

That's pretty cool!!!

 

I think for Grins and Beer.....I'll run your specs thru the EA3.3 and see what if any diffrence there is compared to the EA3 version?

Oh by the way..You'll miss out on the Bass Master Tournament going on at are lake? They have 160 Bass boats out on the l;ake today and tomarrow...and Plenty of Locals.. The TV media and News Media is all over the place!! LOL.. They say there's about 3000 Fishermen out on the water this morning!! Damn!!

RJ

 

Really??? Did you ever get your boat home? That's sounds cool you goin down there?

 

No not yet...I'am waiting on the guy to get all the stuff together..he found all that goes with the boat..but he just bought new lights for the trailer and hasnt had time to hook them up yet..He's been super busy at work..and plus he's taking a couple courses in college....

So I think in a few weeks, I can go pick it up...?? LOL..

I'll probably go down this evening and watch the check in..Hell maybe get on ESPN? or the local news...this time for a good reason!!! LOL..

RJ