well, for what its worth, its interesting jeff that you didn't throw in the DD into your comments
a) we have a Dyno Dynamics unit - stock sti is around 215
b) it reads "low" (only when you have people reading this forum saying "how come I was told my car puts out 80whp more") - but you _could_ correct that (but we dont). it doesn't matter really except for proven power bragging because its all relative from beginning to end, but in any case, you can still correct to 'known' values to publish fancy graphs if you really wanted to. We _could_ correct the 215 to 300 and go from there but of course we all realize where that gets everyone (nowhere). but the point is you have complete control over it. I know for a fact one shop here on Nasioc is using a correction factor on _everything_ !!
c) we try not to use atmospheric/ambient correction - which lowers our numbers even more (but we publish them and the dyno automatically stores what the correction factors would be if used) - and we always run an ambient + an ambient intake temp probe. basically, sae is useless for turbo cars IMHO except for getting higher numbers than you should. But when operating its good to know the ambient intake when tuning and making your own comparos etc..
d) the load holding and ramping is the best I have used for what we need to do (soobs) (I have used DP, Must, DJet and that sweedish thing)
e) this forum annoys me that people dont publish the cor factors and the ambient data. I've seen waaay too many "cheater correction graphs" its not even funny. I too can post a "600 whp" graph, very easily of course !
but the biggest 'game' is the over-fan game... anyways we try to simulate 60 mph for averages, and do a few 'no fan' pulls for god measure, but some guys are running 120mph worth of CFM into those scoops !
f) even though we run uncorrected, people always want to get a "corrected to mustang" or "corrected to dynapak" number because of certain post-whores on nasioc :-)
g) but most importantly, with the DD, it always keeps the 'raw' data - you can show corrected, or uncorrected, etc. so yo can compare things but it still keeps the raw stuff regardless of correction. In other words, you can show it a certain way, but it doesn't mangle the data.
h) The "shootout" mode actually makes it difficult to 'fake' any data unless you trick the ambient probes, but still, I have been discussing this with a number of DD users here in the us about coming up with a "american shootout mode" with no ATC correction, more realistic intertia values and ramp rate of 100. This makes it 'level' for all. but no one wants to use it, it seems, which means most people are getting more out of their correction/parameter values than maybe they want to admit ?
i) what I especially like is you can change tire size, you can change gears, you can run at any speed, the graph is pretty much the same (if you have the right ramp rate and the fans to support it) and
j) that last issue, the ramp rate, is what you are talking about. With fine control over the ramp rate, you can actually do a lot of different kinds of things. And it DOES directly affect your graphs. The DD has awesome ramp rate control, you can ramp down at the controlled rate and do a graph "backwards" if you want - and it does it well (again, if you have the fans and balls to do it on your map, that is). Want more boost ? lower the ramp rate. Want to tune that wastegate right up to the edge of spool ? Ramp rate and hold again. But this directly affects your dyno graphs, the rate you use. And if you try to use a correction factor, ramp rate affects it as well (yet another reason not to). So anyways, a common 'rate' is also important when comparing the same car. I actually do several pulls at different rates on baselines because it affects different things. the subtle point is the DP torque numbers are "difficult to refute".
anyways, other dyno drivers (or others) flame away, I think what we are doing is the "right" thing to do, but I know for a fact the noobs are reading the forums saying "well, they told me its supposed to be 60 whp more" - it makes you think all the published stuff should be corrected sometimes