How accurate are the Computer Dyno's

[fifesjeep]

I just finished plugging all of the information into the 2003 dyno (computer) and I was wondering how accurate this is? Has anybody used them before and what was the difference from the computer simulated to the actual pull? I know mechanical efficiency plays a part as-well but, I'm looking for your thoughts etc...
Here is what It gave me....

2000 rpms = 142hp, 373 ft-lbs

2500 rpms = 186hp, 390 ft-lbs

3000 rpms = 231hp, 404 ft-lbs

3500 rpms = 280hp, 420 ft-lbs

4000 rpms = 330hp, 433 ft-lbs

4500 rpms = 377hp, 440 ft-lbs

5000 rpms = 416hp, 437 ft-lbs

5500 rpms = 435hp, 415 ft-lbs

6000 rpms = 441hp, 385 ft-lbs

6500 rpms = 428hp, 345 ft-lbs

7000 rpms = 407hp, 305 ft-lbs

7500 rpms = 382hp, 267 ft-lbs

I did the formula by hand using the books and they were a little off but similar... (This being slightly higher). Any thoughs or ideas of what I should see on the actual dyno...

[jeepsr4ever]

They are suprisingly different from program to program if that helps. The programs that require the most amount of information are usually the most accurate.

[BREK]

Try this stie www.wallaceracing.com they have a load of different types of programs.

[fifesjeep]

Hopefully somebody can give it a try and test it with their dyno pull...

[Ghinmi]

I get very different numbers in Engine Analyzer 3.0 versus the Dyno 2003 program you just posted. EA has a flow file for stock AMC heads so I built an identical engine in each program. They came up with fairly similar peak horsepower numbers but the torque numbers were way different, with Dyno 2003 being much higher (over 50 ft-lbs). Dyno 2003 seems like the better program though, there's a lot more information input. Either way, they're both just computer programs and I wouldn't trust the numbers at all. However, they're good for comparing cams and such. Just my 2 cents.

Greg