nitro69

Hello, am a newb so thanks for all the great info on here. Am new to the lt1 but far from new to car building so my question is with a 125 shot nos kit wet system that I have installed on my new lt1 motor (95 trans am 3000 miles on it) with a couple mods but basically stock. I have used tuner-cat to pull timing in the upper map column's of the main spark advance and the extended spark advance columns (90-95-100) 3000-5500rpm, went down from 33 to 31 on all of these timing tables. Nos says that this is fine on stock setup up to 150 shot so does this seem ok with just 2 degrees taken out?I know the 2 degree per 50 shot is what should be but with Nos saying its fine with no timing adjustments? Just want to be sure before flicking the switch. Thanks

Injuneer

The problem with doing the nitrous tune in the PCM is that you end up pulling timing, and your non-N2O performance suffers due to the reduced advance. The best thing to do is tune the PCM to maximize NA power, then use an external box to retard the timing, ONLY when the nitrous system is activated.

Take a look as the MSD Digital-6 box.

nitro69

Thank you for reply, and understand the external box for timing but at this point removing timing from the upper tables I notice no difference in performance and yes maybe on the dyno I would see some loss but with just 2 degrees out I feel nothing different and it really doesn't show much different in data log. Do you know what the stock setting in the upper tables are? Are they 33 or has somebody been in here before(in the pcm) as i do notice other changes such as rev limiter, 255 mph speedometer setting ect. So I guess If it was normally 36 degrees in upper tables I wouldn't know what I was missing?and I just dont know if I should trust Nos saying you don't have to pull any timing for 125 shot? Thanks

Injuneer

I have what I believe is the stock timing table in my online scanning guide, but it only goes up to 4,000RPM:

http://www.injuneer.com/ScanMast.html