I logged some non nitrous WOT runs last night. Tank is full of 87 octane. Engine temp at 190. Timing at 3000 rpm was 22*, 4000 19*, 5000 14* and 5700 was 14*. No knock retard.
I'll run the truck low on fuel and fill up with 93 and log a few nitrous runs.

 

Alright... I filled my bottle, replaced the plugs with NGK BR6EF filled up with 93 and bought a bottle heater. Bottle pressure is ~950-1000psi.
With the engine warmed up, I logged a 75 shot and right away noticed 3* knock retard. With the scanner I commanded 4 degrees retard, and went WOT again. I did 3 WOT runs with no knock retard. Stock O2 sensors were running ~ 890 mV (I don't have a wideband). Am I on the right track?
If this seems reasonable, I'm going to put the 125 shot in tomorrow night and pull 7 degrees before spraying again. If all seems OK, I'll go to the track Friday night.

 

Get a wideband. You're playing with fire.....but you probably already know that.

 

While sparaying, the stock O2's are reading rich. What you are saying is the stock O2's don't have enough fidelity to know if I'm in a safe zone while spraying?
I don't want to go lean and burn up my motor... you being in alaska know the racing season is short and the temptation to put in the bigger shot is really high. If you say its unsafe to rely on the stock O2's, I'll wait until I get a wideband. Once I do get a wideband, what air/fuel ratio is my target while spraying?
Thanks your your help.

 

shoot for 11.7 or so to stay on the safe side. you can read the plugs from there and push it a little harder if you waint. definately get a wideband.

 

+1 to a wideband. They help alot with tuning. With you using nitrous and tuning yourself u definately need one.

 

I take it you are not on a stock timing table anymore. Your tune is probably to aggressive for the jug. load a stock timimg table and hit it with the 125 and see if you get any kr. Then again, if you blow your engine , it costs me nothing . Wideband recommended here as well!

 

Stock tune i ran 150 shot for years and years, I thouroughly believe in reading plugs with N2O rather than a wideband, the plugs dont lie!

 

I'm still on the stock timing tables.

 

If you left the stock timing alone and tuned by reading plugs, is your final adjustment the fuel jet on the wet shot?

Does anyone know a good reference about reading plugs?