Thread: Colder Plugs.

Ive been running the 1 step "colder" NGK Iridium LFR6AIX-11 For a lil over 1 yr (about 10K miles) No problems or issues. Im on the turbonetics Reflash.

So far on 91 octane i can run 14-15psi with no detonation, BUT if i turn it up to 16-16.5 psi i get very very slight detonation on 91 (thats all we have) so im forced to go buy a few gallons of 110 octane if i wanna run upwards of 15psi

My question is: If i go another step lower (for a total of 2 steps lower to the 7 range) on my plugs, would i be able to run more Boost with out detonation??

Before you say use better gas (like 93) best we got is 91, Not going to E85 either so save that one too lol and 100 & 110 both run $7.99 per gal so NO

Worse that can happen is a buy the 7's and they foul up and i have to go back to 6's (and ill be out a lil $$)

Thanks in advance guys!
Cornelio.

It also may be too much boost on 91 octane. Every engine will have a limit on when detonation occurs. Increased boost causes more heat, higher compressive forces in the combustion chamber which eventually leads to some knock. Colder plugs may help for when you are boosting 16+ but the downside is driveability when not in boost. Other than plugs there is adding octane to the tank which you mentioned or meth/h20 spray, or possibly a much better intercooler.

Thanks, i do understand WHY knock happens, and i guess im not gonna know 100% if its the 91 octanes Limit OR the heat from the plugs? Only way to know is to try.
and fouling the plugs off boost I dont think will happen (well i hope), I make sure to exercise my cars boosting equipment daily

water/meth injection is something im going to look in to (but i fear they cost allot haha)

The cooler plugs will may help a bit with the heat at high boost, it just may effect slight effect of driveability when not boosting such as lowered MPG's due to poor or incomplete burn in combustion chamber. I would try that first. I don't think they'll foul at your high boost levels. You can get a pretty good meth spray kit using your windshield wiper fluid container for $300. It won't have the extra do-dads such as low level warning but it does have adjustable boost sensor (the boost setting you'd want it to kick on). For your application i would do it around 10psi to give it a buffer to kick on and get spraying by the time boost shoots up to 15+. You may have to get some tuning though as it will richen up your fuel mixture.

Me have No tuning device LOL so meth might not be for me at this time.

Im gonna go to the shop, maybe they have a set of the 7 heat range iridium plugs laying around (they have so much stuff lol)

You can add 1 gal of xylene to 9 gal of 91oct that'll get you ~93.6octane. Or you can do 2gal of xylene to 8gal of 91 will give ya ~96octane. If you use xylene add a few ounces of mystery marvel oil for lubrication. Xylene is 117 octane. Some people use toulene but thats 114 octane. I haven't bought that stuff in a while, but i use to get it in 5gal drums for about $50 bucks at paint shops.

Thats interesting, My cousin does Electrostatic painting (like powder coating for fences) he has xylene always.

I did stop by the shop, talked to the tech that built my engine, he said 2 step colder plugs (7's) should be perfect for the boost im running. So im gonna try the plugs first, if that doesnt help any, I will try other things.

No one on here from what i know, uses 7 range plugs with FI, They all stick to 6's so maybe we learn something new?



Side note, They have a TT 99 Viper GTS Made 1100 lb ft TQ and 980something Horse to the wheels with BONE STOCK INTERNALS!!! @ 14psi.

I run heat range 6 and I'm N/A, if you are boosted you should have absolutely no problems with 7.

i ran a 2 step colder ngk plug in the sentra on 22lbs. out of boost ran like a champ in boost ran like a champ. i would say a step colder for every 10lbs of boost

I ran 2 steps colder for a good while without any issues. Going to try out 3 steps colder soon

let me know how that works. how many psi you hitting?

yeah im gonna order the 2 step colder plugs and see how that goes. NGK Iridiums

i run LFR6A. 12psi.

Originally Posted by stealth

i run LFR6A. 12psi.

I also see u run 440 injectors, not good!