Nitrous guys inside......

[slow04]

Recently I've added a N/X kit to my truck (special thanks to Mitch,Bill,and Mike). I've been hesitant to spray it until we've had a chance to datalog the parameters.Well yesterday was the day,and after a few hiccups with the wiring we tried it out.Now our tuner wants us to use straight C16 fuel in any race applications and nitrous is no exception because of the timing in this particular tune that I'm using. I didn't have enough C16 so I used a combination of fuel to raise the octane.The mixture was about a 1/4 tank of 93,five gallons C16 and about 10 gallons 100 unleaded.We put in the prescribed fuel/no2 pills for a 50 shot and took it out and gave it a go. The first run we had to back out because the A/F went too lean around 13.5,so we went back and changed to a richer fuel pill,and tried it again.A/F went back doen to 11.7...Now heres my question...why did it go lean with the proper combo of jets.1. because of the supercharger? (boost) or 2. the fuel combination. After thinking about it last night I know that the 100 unleaded is oxygenated....Thanks for any input