Danville has always said that the wheels come on a little quicker and I can buy that by the surge line difference, but they definitely are giving up the very top end to do it.
Widening the map is having your cake and eating it too, takes a lot of engineering to pick up a few lbs/min either way. Makes you wonder where we'll be 20 years from now...
Please understand that my point is only to clarify the data, but the above statement regarding 'surge line difference' isn't 100% correct.
The surge line has little-to-nothing to do with 'getting into boost' quicker. The speed lines indicate pressure and flow for a given wheel speed. (for reference, note the speed line closest to 77krpm; both flow AND pressure are greater at a lower shaft speed with the O.E. wheel) The indication is that the O.E. wheel is making more pressure at lower shaft speeds which would have the effect of 'coming into boost' sooner. If the surge line is further to the left it means that you are flowing less air in that region, just as you would with either a smaller wheel, or one that simply flows less air overall.
I do agree that 'widening' the map is indeed the goal, but it should not be at the expense of flow and pressure vs. a given shaft speed. That's actually working backward, and, as you can see clearly in the map, it's also at the expense of wheel efficiency, which, honestly, is the most important factor for a proper match. Just because a wheel has a peak flow of XXlb/min, it's not really 'better' if efficiency is several points off at that flow rate, or if that peak flow requires more pressure (and heat) to be achieved. And, as you can see, efficiency is several points off, throughout nearly the entire map.
The real trick is to widen the map while still retaining the same, or greater efficiency, and also increasing total flow.
On the latter point, I also agree; I remember vividly when, 20 years ago, a wheel was considered 'excellent' if you could get mid-60% efficiency in the center of the map. Now we're flirting with 80+%, so, yes, it will be very exciting to see what the future holds.
One final point, but it's important enough to bear repeating; Borg Warner didn't just "post a graph", nor is this just a Photoshop exercise. The test process they use is 100% transparent and repeatable, in a lab environment, using the most sophisticated equipment available.
To assume that this data is skewed or otherwise manipulated would be unwise. 
op:
