How to read a compressor map

OK, fortunately a heap of the hard work has been done for me here: Mazdaspeed Forums
but figured i would add this in here anyways, with a bit more of my own information...
firstly you need this table:
http://i895.photobucket.com/albums/a...20Maps/300.png
all the nasty maths/assumptions etc are in the mazdaspeed thread, you can go read it if you want...
19psi = 2.6 bar (1 bar = normal atomspheric pressure, so 1.6 bar = pressure being pushed through turbo 23psi, take away IC pressure drop + lack of effieciency of taking air through a filter and you get a reading of 19psi...)

now, in order to "read" a compressor map, i'll show you why the k04 is considered "undersized" for our engines...
they're great for pottering around town (ie build boost easily/soon in rev range) but terrible for the :jerk: factor on a dyno...
http://i895.photobucket.com/albums/a...4_modified.jpg
ok, for the k04 (stock turbo) i have mapped out 19psi (why? cause lazy... and it's already highlighted...) the first vertical yellow line signifies 3000rpm, it's sitting ~70% efficiency (that's good!) now, the 2nd vertical line is at 5500rpm, still holding 19psi... and it's off the compressor map... so, it's less than 60% efficient at this point in time (ie, it's like a good politician, blowing a heap of hot air)
(disclaimer, im not 100% certain this is our stock turbo... map, but it's a k04, just not sure it's the right variant)

I'm now going to show the 2 "best" aftermarket turbos that should still maintian a decent amount of drivability... the GTX2867 and GT3071r

now, if we look at the same "mapping" for a GT3071:
http://i895.photobucket.com/albums/a...r_modified.jpg
Once again i've mapped out 3000rpm, 5500rpm and added 6500rpm.
At 3000rpm, this turbo is sitting ~65% efficiency, at 5500rpm, 77% and 6500rpm, 72%
granted due to it having a larger "hot side" it takes a little longer to respond at a given rpm, but it's also putting less strain on the engine, as the air entering is nowhere near as hot.

Finally, the GTX2867
http://i895.photobucket.com/albums/a...R_modified.jpg
once again, mapped out 19psi, with 3000rpm, 5500rpm, and 6500rpm, this little turbo is pretty damn impressive, due to a smaller "hotside" you'll get a better respsonse than the GT3071, but it has very similar efficency level.

The catch with the GTX2867 over the GT3071, it doesnt push as much air, so in order to reach a certain power level (250kw for example) you'll have to run ~24 psi in the GTX2867 whilst the GT3071 might only need 20psi.

Anyways, hope this helps people :)