So I pulled my plugs again today because of a Blow out problem on 4th gear pulls, to find I had yet again melted the electrode on my stock heat NGK Plugs. I know the electrode is melting because the temperature in the cylinder is to hot. so my question is, should I be using a colder plug or just be gaping them differently. I was using stock Evo 9 NGK plug and stock gap. Also I am running E85 around 36PSI.

 

You should at least be using the 8 heat range with your mods.

Edit: Stock plugs is why they are melting. Are you sure you are using the correct plugs and not the plugs for the VIII non-Mivec head?

 

Running 36psi your using stock heat range plugs? You should be using 8's or 9's.

 

Which turbo?

 

Which electrode is melting? Center one or the ground strap?

Have you measured EGT?

 

Im Running a ported stock 9 turbo. it peaks at 38 then tappers to 32PSI & my BC is turned all the way up

I will order some heat range 8 plugs Thanks for the input guys

 

Here is a Pic of the plug, Sorry I took it with my phone



As for EGT, all I have done is check my wideband when this happened and the car was not running lean or anything. I dont have a EGT installed in the car yet, just a wideband and Boost.

here are the other Good Plugs

 

this is what you need http://www.briskracing.com/product.php?productid=91 or you can use a denso IKH24 but i am going to use the silver because of the much better ignition properties

 

^+1

 

if those plugs have not been cleaned...

there SHOULD be carbon on the threaded part of the plug. Something is not right.


well , I don't know , maybe E85 is different.

 

are you reading afr in gasoline or what?

 

yes E85 is different not much carbon if any

 

I always tune with help of EGT. It gives valuable info from the heart of the engine. The combustion chamber.
Its a wonderful thing to see EGT go down when you add timing. Too little timing sends unburnt fuel to be burned in exhaust mani. Those hot gasses recycle with back pressure. I like to keep egt low as possible while making as much torque as i can. Low EGT is a happy engine. I like to see 800C or less.

Plugs need to be tight. They cant get rid of heat if they are not torqued correctly. Maybe try plug reading after pull? You can read both A/F and timing on the plug itself. Not really a better way to check tune. A/F gauges can easily get 1 point off. How would you know without cross checks? You may simply have too hot of plug, but I doubt it.. With e85 and good tune you can make 600whp on heat range 6 plugs without melting electrodes. But always better to error on the cold side when selecting a plug. problem here is when you select a cold plug to keep WOT pull happy, they dont get hot enough to burn clean during normal driving. Then they foul and misfire after just a few hundred miles. There no such thing as dual heat range plug. But that is what is needed in our high output engines.

 

basically the reason why its melting is because your on the wrong heat range use either an 8 or 9 heat range plug another benefit is a nonprojected plug like the brisk ER12S

 

Unfortunately it's the wrong electrode that's beling melted. Only the center electrode will be affected by changing heat range of the plug. Heat range will not change the cooling of the ground electrode at all.

That plug has been damaged by extreme temps that could be caused by detonation and/or severely retarded ignition timing. An EGT probe would be a very good way to check for retarded timing.

Note that when a stock ECU detects knock, it retards the timing to reduce detonation. The chamber temps go up dramatically when that happens.