Since I have had a lot of request for this, it's an Excel file.
This converts Dyno Dynamic's/Dynojet/Dynapack/Dynamic test system . It used to be on Shiv's website under the heading how big is your horsepower to get an idea if you made this much on a Dyno Dynamic's it would = this amount on a Dynojet. Again variables can be different it's just an estimate.

 

I think that calculator is a little out of date.
Dynapacks read higher than Dynojets, which read higher than Dyno Dynamics.

If I had to do a calc for an Evo, I'd say:

Stock crank rating: 271HP

Dyno Dynamics: 205whp (Div crank by 1.32)
Dynojet: 230whp (Div crank by 1.18)
Dynapack: 246whp (Div crank by 1.1)

Also, loss isn't a percentage per se as power goes up. That makes it even more hairy.

 

This is from The Vishnu site from a while back

 

I know where its from originally, but maybe it was taken down because the test pool didn't fit so great anymore? Regardless, I still don't agree with it based on what I've made on different dynos I've run on across the country.

I'd find it very hard to believe that my car that makes 409whp on race gas on a Dyno Dynamics would make 480whp on Doug's Dynojet and an earth crushing 572 HP at the crank! That's what I mean about whp loss not being a static percentage to the crank. I think the 409 at Dyno4mance would be more like 460 at Doug's and around 525HP at the crank.

Just a different opinion, but I know for 100% fact that most Dynapacks read higher than Dynojets. TurboXS made over 250whp in a stock 03 Evo VIII awhile back! All dynos aren't even created totally equal within each other within the same brand.

 

Not always true . The Dynapack up here reads 7.5% lower then the local Dynojet here (Both SAE corrected and I have been on both).

That spreadsheet is really dated and different dyno's can't be compared.

 

Hence the "most". I agree with your point totally.
Knowledge in ATL reads low for a dynapack too, IIRC.

 

There were two versions of the great equalizer.