I just did some data logging on my 2015 A8 Z51 with the stage 2 E force. had some interesting results. The last time I had it on a dyno it made 520whp on a Mustang dyno (Mustang dyno typically read 15% less the Dynojet). That day the WOT AFR was in the 10s, very rich using the Edelbrock tune. That was just the stage 2 E force and a ported Kaltech TB.
I recently added the new GM cold air intake and the Borla secondary cat delete X pipe. Ive seen dyno videos posted of 45whp gains on ZR1s and 35whp on Z06s. Well I have say after doing a few WOT pull today the car picked up big time!! Id say conservatively 40 hp gain. It sounds crazy mean now as well. Car feels like a total ANIMAL!!
Before the X pipe the logs shows just over 9 pounds of boost after the X pipe just a little over 8 pounds of boost.
Before and after the X pipe my IAT started around 121* and after the pulls went to around 131*.
Before and after the X pipe on WOT pulls the car pulled timing a few times over the pulls, around 2 degrees.
So i was thinking the X pipe and GM CAI would lean the car out but as some of you guys have told me it went richer. As i said before the X pipe the Edelbrock tune at WOT the AFR was in the 10s. reading the AFR from a bung i had welded into the drivers side of the X pipe at WOT my AFR was now pegged at the AFR gauges richest possible reading of 7.4 AFR, sure it was even richers thats just the fattest the gauge reads.
I had planned on saying with the Edelbrock tune but that is no longer an option, Ill be calling Vette Doctors tomorrow to set up a tune.

 

Still not sure why it went so rich?

 

Thinking it might be going into Cat over temp protection.