Nerds! -- stock WRX compressor map FINALLY found!

Well, it looks as if this little guy isn't so tiny afterall. Suddenly, 18psi in the midrange doesn't sound so insane anymore.

:banana:

 

soo uuhh.. how do i read this thing? and what is it doing at 5psi?

 

that's what she said....

 

this was recently posted on nasioc. there is more info there if you need.

 

You need to calculate your mass flow rate versus pressure ratio. Your pressure ratio is that above atmospheric, taking into account IC pressure drops and what not.

As you calculate your mass flow rates for different RPM, you plot them at the pressure ratio you are going for. So say you want 20psi at you intake manifold. Thats 20psi + 14.7psi atmospheric + IC pressure drop. You then calculate how much air you are using at a given RPM and plot it on the graph. Your points will form a straight line across the map. Hopefully your points go across the most efficient portion of the map (the contour lines have a percentage on each one, which is the compressor's efficiency) and you don't want to cross the surge line, which is the left edge of the map. Hope this helps.

I can post all of the equations later tonight when I get home.

 

the compressor map is actually showing volumetric flow rate, and not mass, but everything else piddster said is what you should follow

if you dont get what he is saying read a book called maximum boost.

Ben