Originally Posted by slider2828

I thnk 7's are one step too hot... In accordance and my experience 8's are perfect same is said on Phase2motortrends site when ordering plugs

I am runing built 86mm block, HKS 264/264 step 1, bc head stuff, 2871R .86 ar running dyno'ed and dailyed on 17.5 psi making 330WHP on a Dynodynamics so shoudl be close to 380 and I get about 310lbs of torque on the DD. I use BKR8EIX, which are the iridiums. Gap also at .028... Stock coilpacks as well with a Sun Auto GT Power Thingy....

I never get sputter on the track or daily... you can easily tell heat range issues. The grounding strap which is the thing that looks like a hook over the eletrode, that is the part you can tell the range. If its too hot the strap is all white, the whiteness should only reach the bent of the strap.... Done.... Never had problems....

Also in terms of negative setups. I relocated to full size battery to the rear. 2 gauge monster cable front terminals to back. 2 gauge battery ground o chassis. All grounds in the front lead to one point on the chassis, with homemade grounding kit, head, block, intake manifold, strap grounding point for coilpacks. Also Smaller ground leads (16,14,or 12awg) such as ignitor grounds is distributed to a grounding block then linked to a single point with 8awg grounds to where my other grounds are. Better the grounds the better the spark....

Originally Posted by fliprayzin240sx

Thats what I was gonna say, a good rule of thumb is for every 100hp above stock, you go down another heat range with NGKs. Stocks are 6s at stock 180 whp ish. You are way more than double that, I'd go down to 8s and gap them down to .030. If its blowing out, start tapping them down closer to .025 if need be. I've got a guy out here thats been building SRs for over 20 years. He said from his personal experience, stock OEM coilpacks/igniters can handle up to 600hp with no issue. No point of upgrading coilpacks.

On my GT3582 at 1.8bar, I'm still running stock S15 coilpacks with NGK Irway Iridiums 9s. Already came pregapped at .030 so I never touch them. Only fucking catch is they cost like $25 a pop out here with the shitty exchange rate. Will probably order some copper plugs and see if they work just as good. Figured if coppers work, I'll just change them more often like I used to do in the states (roughly every other oil change but they only freakin cost 1.25 per plugs).