Originally Posted by ace32x

im running 1 step colder with meth and water injection and its still not cold enough, preigniting up top in the rpms around 6k+ so i wouldnt try stock range plugs. i need to order some 2 step colder but i cant seem to locate any >.>

Originally Posted by binder

top on the list when typed into google:

http://www.conceptzperformance.com/C...20081230220008

http://www.injectedperformance.com/n...for350zg35.htm

even AMAZON.COM sells them

http://www.amazon.com/NGK-LFR7AIX-Ir.../dp/B000HDH1GG

edit, summit even sells them in heat range 7

http://www.summitracing.com/parts/NGK-2309/


BTW, those are heat range 7. OP, do not buy heat range 7. All of those places also sell heat range 6 which is the most i'd ever go for 400hp builds. I ran heat range 5 up to 450hp with no issues on pumpgas.

Originally Posted by binder

If you are pre-igniting then you need to adjust the timing.

1 step colder should have no issue on it as there are people running no injection at all with straight race gas into the 800hp range without any issues. They don't have any water or meth to cool down with straight race gas and they aren't having issues.

I'm running e85 which is a lot cooler than pump but 650hp on 1 step colder plugs with no issues at all. I was mid 500hp on 93 octane without any signs of detonation or preignition with 1 step colder as well.

Unless you are never going to drive it on the street i probably wouldn't use 2 step colder plugs. They will foul quite a bit easier under normal driving. That and there isn't a proven reason why until you are up around 1000hp and never drive it around under vac map (ie, track car only).

Originally Posted by ace32x

I have Denso 8s in atm. Looking for a 9 heat range like hks makes
unless the denso's are labeled different the fxe24hr11's. come up as an 8 but maybe theyre just 1 step colder?

Originally Posted by ace32x

it was preigniting regardless of timing tuner tried adjusting timing a few times and still was happening any where between 16 degress and 24, what he said anyways I wasn't the one tuning

Originally Posted by binder

They might be on a different scale.



Something else is going on then. There is no logical reason to have preignition with something 2 steps colder at that power level.

Maybe he was just going by the crappy stock knock sensor thinking that the engine noise was preignition. The stock sensors pick up tons of random engine noise. I had to tune out a bunch of it in my knock maps. I was using 110 octane so i know it wasn't knock. I still had tons of noise on e85 with low timing so it's just a sensitive sensor.