I'll agree. My bike plugs were 25$ each. Worth it for a expensive engine.

But back on topic for the charger I'll be trying the 2 steps colder iridiums, and gapping them to .40 and see how it works out.

Philly, how much boost are you going to run? What is the static compression on the engine?

Currently running 11psi supercharged on stock engine.

So the stock GM kit on a stock engine. Ill be getting a smaller pulley in the spring...but just down to 3.1 till I learn to tune.

I have no problem gapping the plugs with a ramp style, but also take my time.


Still NGK has recommendations on how far to take the gap from stock, which does not matter what kind of gapper you use can create a broken ground strap.



FU Tuning

Philly- Yes 1 step cooler should take care of it up to the boost that your are running, any more and you will have to go cooler. Please see the attached below for further information.

Addicted-- Yes going plus or minus 0.08" of what the plug comes out at example -11 would be 1.1mm or 0.044" so we would have plus or minus 8 here. Going to 0.10" is where we see the ground strap weld start to weaken on a standard style plug.


General reccommendations:

Heat range Static Compression

4 9:1 or less
5 9:1-10:1
6 10:1-10.9:1
7 11:1-11:9
8 12.1:1-13.5:1
9 13.5:1-15.00:1
10 15.5:1-17:1

First we base the heat of the static compression, not dynamic. This will give us a base heat range, then if there are power adders that is where we adjust.

Nitrous

8 Cyl = General rule is one range cooler for every 100 horsepower. I would reccommend one stage cooler for anything up to 125hp. If going further to a 150-225 shot we would need to go cooler and non-projected style plug ( this will lessen the chance of the ground electrode from over heating and melting and causing serious piston damage). For a 250-325 shot go three steps cooler and non-projected.

6 Cyl = A range cooler for up to a 75 shot. A 100-150 shot will be two colder and non-projected. A 175-250 shot would be three cooler and non-projected.


4 Cyl = One cooler for up to a 50 shot. 75 shot to 125 would require a 2 step cooler and non-projected. A 150-225 shot would require 3 cooler and non-projected.


Boost


-- For every 10 psi we reccommend dropping a heat range cooler
-- For 25-30 psi we would reccommend non-projected to prevent blow out
-- For 30 psi and above we would need to go non-projected and a low angle ground electrode or possibly surface discharge.

Keep in mind that we cannot find the correct heat range if some of this data is unknown.