Quote:
Originally Posted by vicious_fishes
Even the most rudimentary understanding of centrifugal force should tell you to expect this.
I think you mean angular momentum. But let's do some math on this...
A rudimentary understanding would say that it's probably more-or-less proportional to radius-squared for compressor wheels, so...
67mm diameter divided by two is a 33.5 radius, squared is 1,122
71mm diameter divided by two is a 35.5 radius, squared is 1,260
...or a difference of 12%.
But note that at a pressure ratio of 2.5, and 55 lb/min of flow, a GTX 3071 has to spin about 132k RPM, and the G30-660 has to spin just over 145k. Or a difference of about 10%.
So a net 2% in favor of the G30. Roughly. Very, very roughly.
By the way, while looking up the compressor maps for this little thought experiment, I noticed that there's now a G30-770. Similar diameters as a GTX3071, but the compressor map extends just past 70 lb/min. Looks very promising:
https://www.garrettmotion.com/racing...eries-g30-770/