I'm sure this has come up before but I missed it. Whats a good spark plug to go with when running 9#s of ATI intercooled boost? I'm just trying to gather all the facts before i order this thing.The colder the plug the better?

Any other things that will conflict with the blower?
Thank you

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91 Formula
305 TPI 5speed
1LE/G92/WS6
Custom cold air intake w/K&N, SLP airfoil, ported plenum, TB coolant bypass,Crane AFPR (47psi),94 octane,Crane Extruded Alum. 1.6 full roller rockers, Timing set from 4*BTDC to 10*BTDC,MSD6AL, Holley 9mm Annihilator Laser shot 50 wires, Ac Delco cap,rotor and plugs, Bosch O2sensor, SLP 1 5/8 headers,SLP catback,3:73s,JET 195* fan switch, Macewen white face gauges, Autometer gauges, Zoom hi-performance clutch.
Street legal with stock throttle body, runners,intake manifold,cam, and heads. Coming next..9# Procharger!

 

well, run the stockers and just read the plugs after a few 1/4 runs and see how they are. i have the 12psi kit and i had to use 2 stage colder plug and my best plug i can reccommend are autolites. they are cheap and do the job. i tried every other brand and didn't like them. autolite worked the best for me and some other people who have had the kits in the past.

 

Usually about two steps colder is the ticket. Of course the purpose in this is to reduce the likelyhood of the hot plug igniting the highly pressurised mix in the cylinder before the spark even lights off (preignition). This is different than detonation but simular & will have the same effect on the engine.
As far as choice goes, stay away from all the "fancy" plugs. U-grooves, notched or multiple electrodes & other such things will not help here and can contribute to preignition. Also platinum can contribute to preignition. Good old fashioned copper core plugs are best. Autolite, AC Delco, & Champion are all excellent. Just use the basic standard plugs though.
I guess you're still running the iron heads with the tapered seat sparkplugs? If so I used AC Delco R42TS plugs on those heads in most cases with N2O or blowers.
Basicaly what you're shooting for here, is a plug that is hot enough to not foul with carbon during daily driving, but one that is cold enough not to light off the air fuel mix on it's own before the spark has a chance to. Too hot a plug can take out your engine. A plug that's to cold will not burn off carbon & will foul sooner requiring plug replacement. If you're going to error, error on the colder side. The higher cylinder pressures & temperatures are what makes this an issue on forced induction apps.

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Tracy /AKA IROCKZ4me

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• modified SLP runners
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[This message has been edited by IROCKZ4me (edited December 27, 2000).]