The A/F ratio would be lean on top if (a) the system pressure was too low for your power output or (b) the WUR boost pressure was not adjusted properly or (c) both. This would all be revealed on a dyno run or with an LM1.
RarlyL8 Motorsports / M&K Exhaust - 911/930 Exhaust Systems, Turbos, TiAL, CIS Mods/Rebuilds
'78 911SC Widebody, 930 engine, 915 Tranny, K27, SC Cams, RL8 Headers & GT3 Muffler. 350whp @ 0.75bar
Brian B. (256)536-9977 Service@MKExhaust Brian@RarlyL8