A big problem with Dynapacks is that they can not and will not take into effect the rolling resistance and power loss from the wheels. The other is that because the Dynapac measures TQ output and has to convert to HP, there is calculation error there that can be off.
A dyno can only be as accurate as it is calibrated to do so. It is VERY VERY easy to mess something up and get high numbers and not know it. the biggest problem is where the IAT sensor is placed. Most of the time it is getting false heat from the computer, monitor or the sun.
About 2 months ago I went around to about 5 dyno's around the area and dyno'd my 99% bone stock RSX-S. Dynojets, dynapacks you name it. All the Dynojets SAE were within 3whp of each other at 176-178whp and 130tq. I'm sure if i measured tire temps and pressures and made sure they were equal, then they would all be the same.
The first dynapack I went to, the first pull was 192whp, and the second 199whp... thats over 20whp gain SAE TO SAE. Then we put it on standard to see the "uncorrected" numbers and it dropped to 187whp. That means that it is seeing super high air temps or humidity or something else. I did have the "glitch" that all dynapacks do from time to time but i knew about it so i just did another run to get rid of it.
All in all the dynapack 4000 and the 2000 both were 7-8% higher SAE to SAE than a dynojet was. And that was nearly a direct comparison between them.
Another thing to back this up is that my friends 1995 EG hatch with a K24 in it was making 328whp on a dynapack 4000 and that was with "the glitch" at the track he was only running 11.5 @ 116mph.
My friend/ business partner, was running 325whp on a dynojet in a 2400lb car but he was consistently pulling well over 120mph with 3 whp less BUT 300lbs more? same trans, same gear ratios, same slicks. They redyno'd on a dynojet and lost almost 30whp. from 328 to 299 just that easy, then it was easy to see why their car was slower mph than the heavier one.
It is possible to correect a Dynapack to read the same as a dynojet, or within about 1-2% which is good, but not all can be done this way.
Dynapacks are awesome for tuning because you can load the car up and tune cell by cell, row by row. Dynojets are better and more accurate run to run to get the same readings over and over. I did 47 runs on 2 dynapacks never turning the car off ( on each pack) and i NEVER got a consistent run back to back where as on the dynojet i did 4 runs back to back non stop in a row and got a 1whp varriation.
I know a lot of people prefer dynapack numbers, but it is too easy to get hyped up and then go to the track and be dissapointed.
Another thing i've noticed about sr20ve motor setups is that most, and almost all of them with great setups "200whp+" setups all make 200whp at almost exactly 7000rpm. 6900-7100 on average. donttazmebro's car makes it at about 6300rpm or so which is about 10% sooner and oh look, thats 10% more displacement.
The dyno that Jun posted was making 200whp at about 6300rpm so either it had a stroker crank in it, or like i was thinking, the numbers were dynapack so you need to lower by 7-8% to correct. and when you do so (after removing the glitch pyramid) you get about 205whp DYNOJET and now you are making 200whp @ 7000rpm give or take. Just something i've noticed with nearly ALL good VVL setups.
Originally Posted by Setzer 
The options of a 4-1 is not as easy going in the SR community like honda.
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