14.7/knock w/racegas

[quickbrick]

i was getting my car ready to race my buddys mustang. i put about 5 gallons of 110 leaded in my car. i took a couple practice runs and got 0 knock and 760 o2s. when i race him he takes off the line better than i do but i caught him at the end. when i look at my scanner afterwords it says 14.7 knock 500 o2 . i dont understand. i was running 17psi on the quickspool then dropped to 15psi for the rest of the run. fuel pressure was at 45 lineoff. its about 35-40 degrees outside. i dont understand this car sometimes it runs perfect then the next run will be terrible. i had the car at the track a couple weeks ago and it ran real good, consistant 13.2s. then the next day i raced a buddy and it started popping and sputtering. i think im done racin for the year. hopefully i can get it tuned right next year.

 

[azgn]

could be several things...110 mixed with what?

at that temp, you'll tend to run very lean

is fuel pressure tracking boost? (check fuel pump, regulator, lines, vac lines)

dirty injectors

good luck