I was going to use a air/fuel gauge to try and pick up knock before the "pinging" on a head/cam/nitrous can but i've heard that these things are just a light show and pretty much just ****, anyone on here running one?

 

Wouldn't waste my money.Ya can't watch it going down the strip and they don't peak hold. Ya need one like Performance Trends sells that has an optional recorder that can be downloaded. Very pricey over $500.
The best ya can do is put the money in a good (pill)MSD timing retard that works when the NO2 is on and pull 2*per 50Hp.Then get a dyno tune and see if will take more or less.
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Do you need a msd 6A ignition box to use the retard box? What if I just retard base timing 4-6 degrees (150 shot) when I spray?

 

???

 

Check out plxdevices.. They have a low cost standard 2 1/16th gauge wideband.