[Blowby]

Originally Posted by 907dave

Ok, I know there is no exact answer(too many variables), but how much would you take off of a tune that is "safe" without nitrous?

This is just my way of tuning and I do create a lot of excessive work for myself but that's the methodology in my world.

You just need to know a few things first to have a "safe" nitrous tune.

1) How many bottles delivering the nitrous? PSI fall-off at end of track
2) How many stages? Controlled delivery at higher rpm's
3) Location of nozzles? Impact of hit
4) Delay of delivery? Move to higher RPM
5) Progressive? Control volume at low rpm
6) Bottle pressure? Potency of nitrous
7) WOT rpm shift points? Keep in higher rpm's
8) Total volume of nitrous per run? Ratio to fuel/air (turbo)
9) Current EGT's at WOT without nitrous? Fuel content
10) Fuel added for nitrous? Controls burn speed
11) Peak Tq point in rpm before nitrous? (Dyno) Control peak Tq location
12) HP curve on graph? (Dyno) Jet size / timing on map location
13) EOT during run? Timing control
14) Turbo waste gate? Control shaft speed

or you can just back off a lot (-7 to -9 deg) and start moving back up and you should settle at around -3 / -5 deg in general if you have all the data above documented and feel that you are not causing pressure spikes too low in the rpm range. Just take time to get it dialed in and the more time you spend with minor changes the less it will cost in replacing broken parts.