16-01-2016, 07:09 AM
It means the gt2871r is unsuitable for producing 1.2bar boost at 17lbs/min, as most suitably-sized petrol turbos will be. If you perform those calculations and produce a point left of the surge line (as per the yellow line in the image) you need a different turbo or a different target boost/airflow point. Tbf to the turbo 3500rpm is a very low number to be producing 1.2 bar on a petrol, especially if you want the turbo to be able to continue boosting to the redline rather than becoming a restriction higher up. Not sure if i've missed something, but that compressor map isn't for the T28 either, try this: http://www.mazdausa.com/MusaWeb/images/m...tent07.gif. Crap picture, but you can see the figures on the axes alright.