air - fuel mixture when running track days and H2O tuning?

[d15b7]

hi fellas!

my car is a 2003 Mitsu EVO. stock, with exception of turbo back straight exhaust. computer is stock, no boost controller. i have a HKS Super AFR, which is currently set to all zeros. on a wideband, the car runs very rich, stock. it shows ratios of 10.1 and 10.2 to 1! we get 93 octane fuel here on the east coast, so that is what i use.

i have just finished construction of my homemade water injection system. i'm using the shurflow 100 psi pump and a 6.4 gph nozzle. i have the pressure switch set for about 12 psi. btw, stock EVOS run boost of up to 19.5psi, and gently tail down to about 17 psi at redline....

my main question is:

a trackday is coming up for me (i'm an instructor for the PCA, BMW CCA, Ferrari Club, etc.) and i' like to take my EVO for one of the three days, just to "see what she can do"

i'd like to tune the fuel mixture beforehand; i was thinking of tuning it to about 11.5:1 from 4000 rpm up to 7000 rpm; i was planning on doing the tuning without the water injection. when at the track, i would of course run the water injection as a matter of increased "safety" (knock resistance, EGTs, etc.).

does this seem like a reasonable air-fuel target? most of the guys with tuned up EVOS (more boost, etc.) run around 11.5 to 1. but they are either drag racing or just driving around. this will be track duty; 25 minutes of HARD driving....

i don't have any access to any other diagnostic equipment, such as a knock meter, etc. all i have is a good wide band O2, you guys, and the seat of my pants!

just looking for some good input!

thank you in advance.

todd
d15b7@aol.com