Upsetting Tune

[rob82]

the air/fuel ratios arnt very good

there is nothing smooth about them they should sit at around 12.0:1 the whole way

and never go as ndeep as 10.8:1

there ia alot more to be had if they were to be cleaned up

<{POST_SNAPBACK}>

Actually there probably wouldn't be that much picked up if the AFR where leaned to 12:1. The XR6 chamber design is one of a few four valve heads that doesn't respond to a leaned mixture.

I would be more worried about the fluctuations in boost pressure you where describing. This hardest part of tuning an XR6T as there is a couple of tables that altered. If the boost goes outside a certain bounds then it is no longer closed loop and if not tuned properly it can fluctuate quite rapidly. However if it is soing this you can be assured that they have at least tryed to tune these tables and not just use a fixed dyno duty cycle.