Todd from Protomotive has been doing the tune with those 3071 wheels in the modified K24 housing with great results as I said in an above post..
Its sounds like these 2 set ups are better then my K24/ 18gs.

 

Yes.

John sincerely don'y sweat it too much. With a car as dialed in as yours it will take more than a K24 based turbo to really improve in a worthwhile way. When you are ready go with a set of Alpha 30's.

 

Maybe someone more knowledgeable can help me understand this. The newer 18g and 20g wheels have been reworked as billet designs and modern aero profiles AFAIK.

18g is about 43 lb/min
20g is about 47 lb/min
68HTA is about 47 lb/min
71HTA is about 51 lb/min

Assuming each compressor is being stuffed into a K24, journal bearing turbo with the same hot side treatments and same supporting modifications (fueling, ICS, exhaust, tuning) - how can the 71HTA have better spool, more power down low, and more power up top? It sounds like some sort of physics-defying unicorn hybrid turbo...?

 

From what I was told from Todd at Protomotive in which he got the results from 911 Tuning over seas,,, that the shape of the impeller spins easier and faster then the others at low RPMs..Also as I passed on,,the housing was extensively modified by them.

 

The 24/20's give me >700 whp & that's the most I want to push a stock motor.

 

We had a set of old 20gs on 2002 gt2 and it ran like stink. There are hta billets and Blouch billets.
Both are good and anyone that has k24s it's the right choice. THere is a point where the compressor is mismatched ( too big) and the exhaust side can't keep up. I've seen some 30rs in a k24 and that didn't work all that well.
Markski

 

the combination of a real big compressor and small hot side can provide you a turbo surging .... from 2500 to 3200 rpm at full throttle
this is a sensitive area