Originally Posted by Mr_PharmD
I actually asked a similar question in post#19.
500whp seems to be the cap until the AFR starts to look too lean for comfort. Dz recently found out that the Cobb was able to alter the DME to fix this issue (if any).
Here's a dyno of the RB where afr goes lean up top and i'm sure boost was taper down at the end.
That dyno was Dzenno's car which, as he recently discovered, had miscoded injectors that caused misfire. Back then, we weren't aware of this and attempted to avoid misfire by tapering boost and enleaning AFR targets slightly.