[PoorMans180SX]

I was reading through the EFR thread on NASIOC and came across this interesting quote that Geoff posted from the lead engineer at BW:

"The point of the 7163 was to have a small and light turbo (B1 frame) that will squeak out ~500hp while still spooling/transient as close to a stock-sized turbo as possible.

That being said, if you separate the topics of spool versus transient response - the inertia difference of 7163 vs. 7064 vs. 7670 is significant. We have B2 EFR turbos for people that want bigger power levels! The twinscroll 7163 isn’t for the dynochart crowd, it’s to squeak out 500hp and still feel awesome at 2500rpm. I fully expect a singlescroll 7163 IWG or 7163 EWG to make more top end power. And yes, a 7064C will also make more top end power (especially at very high rpm where dP is more harmful) "