Every car can tolerate a different amount of timing advance for nitrous. It depends on all your mods plus the size of the shot. My car ran 21-22 degrees of timing on a 60 shot with no KR. It could have possibly taken more but I didn't push it. With a 90 shot I am running 18-19 degrees with no KR. I might be able to squeeze more out of it but I prefer the margin. Remember, timing will blow head gaskets much quicker than boost/nitrous will, within reason.
As far as the O2 levels, I don't trust them at all for running nitrous. A friend running nitrous blew several sets of head gaskets with O2's that looked ok. Ideally run a wideband. If you can't, you're probably better off tuning by plug color. That's what I'm doing now until my WB is installed. If you really must shoot for an O2 reading go for 950 (for a '97 - '03).
A stock PCM will give up to 16 degrees on 0 KR, if it hasn't seen KR in a while. That would mean that it's working exclusively out of the High Octane Timing Table.
Well the car has ported heads, ported intake mani, s1x cam, ported exh mani's, 3.25 pulley right now and stock pcm. I was thinkin of a 75 wet shot(workin up in small steps). I guess I should have reworded the o2's wide band, what reading would be preffered, the 12.0 area still?
Doug, I think that's too lean. IMO, a modded GTP with no nitrous should be in the 11.6 - 11.8 range. If you add nitrous to that, I'd look for 11.2 - 11.3. A motor with both boost AND nitrous should get plenty of fuel.
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