Here is some tips taken from another website for those adding a NOS system
1. For road cars & big bikes with say 25BHP to 45BHP extra, a small increase, all that normally needs to be done is a few basic preparatory things. Best to do ALL of the following:
Make sure that it is running correctly! If possible, use a rolling road, with an experienced operator, and if not get an experienced mechanic to check it over...
Fit a new set of COLDER plugs. For example if your stock plugs are NGK-B7HS, for example, then use NGK-B8HS or 9 even, instead. This is one to two grades cooler. They need to be gapped about 10 to 20 percent less than stock plug gaps were originally. This has no "noticeable" effect on power, but means that when the Nitrous is operated, the standard ignition system can still cope with the higher effective compression ratio and still spark. Also if your plugs are "projected nose" type, fit NON projected nose ones! Ideally you want the shortest electrodes you can have! Imagine playing a blowtorch on your plugs. Which bit will glow first? Answer - the bottom earth electrode! Go for shorter ones... Or shorten the bottom earth strap and file any sharp edges and gap across the corner.
Use standard NGK plugs if possible. Avoid fancy expensive platinum, or multi electrode types.
Fit new QUALITY HT leads, Stock or preferably NGK plug leads because they are good!
Make damned sure your fuel pump is good enough! Drive flat out, open (operate) the fuel solenoid alone complete with its jet, and make sure the car or bike is:
a) still performing properly,
b) That there is the correct amount of fuel still flowing from the fuel solenoid! - See the jetting sheet. Pump too small equals melted engine when using Nitrous.
Make sure Distributor cap is clean (or new) Sparking is more "difficult" under the extra effective "compression" of Nitrous Oxide. So, if the spark can track somewhere else it probably will do! This can cause bangs, pops, backfires, and lack of power and flash backs that damage carbs and air boxes.
Change oil and filter - use high quality synthetic oil like Mobil 1 or Castrol RS Synthetic, or similar.
Check with compression tester to be sure no valve leaks exist. A leaky inlet valve can cause manifold explosions, and a leaky exhaust valve will glow and melt and can initialise the onset of detonation in that cylinder.
Check oil pressure against the specifications to try and rule out big end and main bearing wear or other related problems
Check gearbox/diff oil levels! - You should do this anyway!
HIGH OCTANE fuels. The best you can get. Super Unleaded, 5 star, or whatever has the highest Octane rating in your local fuel station! This is important! Or if you want to add some additional octane booster that will also help protect your engine from detonation.
If a cooler thermostat and/or fan switch is available then fit them! A cooler engine will be less likely to detonate or pre ignite the mixture in the cylinders, and it should make more power too.
