Diagnosing Spark Plug Issue..

Here are a few pics of the #1 and #2 plugs out of my car after Lewistown. I am guessing this may be a reason why my car was sputtering out, not sure though.

This is the plug that came out of #2. Notice the ceramic part is a different color on both sides.


This is the plug that came out of #1. Notice the strange coloring around the ground strap.

I hope you're not going to use those anymore after clamping them in that vice.... lol.

What kind of fuel are you using?

Isn't #1 injector the last one one the fuel rail? If your running it out of gas it would be the cylinder without fuel the longest.

I have a dual rail setup so all injectors get the same amount of fuel.

The light yellow color tells me that at some point there was some oil in the combustion chamber. The one with some black carbon on it looks like it may not have been at operating temperature. They definitely look like something strange is going on. Whats your total timing in the upper rpm's?

20 degrees. I am pretty sure I could advance it about 2 or 3 more, but I am in no hurry for another rebuild.

What fuel are you using though?

2 gallons of 110 and 13 gallons of 91.

That yellow-ish looking stuff I've been starting to see on alot of plugs.... it seams like maybe ever since our fuel has been getting 10% ethanol mixed with it. Don't know if that's any thing that might be interest. Don't know about you but every gas station I go to now has blended gas..... as if our gas to begin with wasn't crappy.

Mike do you still get 93 from town and counryr? I hate that crap I also get bad gas from there and my car pulls knock correction everytime. Conoco 91 FTW and 93 FTL!!!!

I also have noticed the yellow tint from fuels with ethanol. That totally slipped my mind. Its hard to say since my engine so much difference but 20 degrees seems pretty advanced for a mix like that. I'm usually closer to 14-15 degrees on 91 octane. With the chemicals in fuel now days its really hard to acuately read plugs. I use my plug reader and study plugs forever and never feel confident, but one trip to the dyno cures any worries.

wait so a place has 93? what town and country? really bad quality tho? Sorry i just moved to town like less then 2 months ago

Town and country has 93octane. Its on hilltop right off of main. Some people dont like it. I havent had a problem with it???

My plugs had a yellow-ish tint after i ran NO2. you hiddin something mikey?

thanks man... sorry to drift your thread

Let me run out and pull my plugs out. I have run nothing but 93 in mine..and 91 from time to time.

not the best of pictures..

#3 is on the left and on top. #1 is on right and on bottom. I need to learn a little more about plugs!
Time for new plugs for me..

Fresh yours look pretty good for boost. Id say you had a pretty good tune going.

I had a baaaaad experience with town and country and their 93 octane.

ts4l wrote:

I also have noticed the yellow tint from fuels with ethanol. That totally slipped my mind. Its hard to say since my engine so much difference but 20 degrees seems pretty advanced for a mix like that. I'm usually closer to 14-15 degrees on 91 octane. With the chemicals in fuel now days its really hard to acuately read plugs. I use my plug reader and study plugs forever and never feel confident, but one trip to the dyno cures any worries.

Subarus really love timing. I was talking to the Autronic dealer out of Canada and he said I should have no problem running close to 25 degrees @ 1BAR running a mix and meth. That is why I have it about 20, baby steps.

04 Wagon Boy wrote:

I had a baaaaad experience with town and country and their 93 octane.

What happened with the T&C petrol? I run it strictly in my '08 and have no problems thus far.

He got a bad batch that had some diesel in it and Subaru had to flush his entire fuel system.

BlackedOut04 wrote:

He got a bad batch that had some diesel in it and Subaru had to flush his entire fuel system.

Holy shit really?

Yeah Town and Country sucks!! I always get bad gas and my car is why are you feeding me this shit? I have heard that usually there is more then 10% ethanol added to it. I have also heard it can water down and give A/R readings. All I know is my car acts up when I run. My fuel learning gets really goofy and my car pulls timing everytime. 93 octane FTMFL!!!!!!!!

I've never had any problem with the 93 at T & C ever.

There is nothing wrong with 10% ethanol in the gas. By mandate in the next year or two all gas will have 10%.

I may soon have an alternative for everyone. We'll see how the meetings go. But I may have a new product for everyone to test out, and its already very well accepted by lots of Subie guys around the US.

BlackedOut04 wrote:

I've never had any problem with the 93 at T & C ever.

Me either

ts4l wrote:

I may soon have an alternative for everyone. We'll see how the meetings go. But I may have a new product for everyone to test out, and its already very well accepted by lots of Subie guys around the US.

Only for Subies? You have intriqued my intrest.

Hopefully it's E85

Oh la la .....

No its for everyone. Just something to help out people who want race gas without the pain and expense.

e85, methanol, e98, nitromethane all eat the crap outta oil. Unless you spend 60$ an oil change on some joe gibbs racing oil or some other racing oil with zinc and phosphorus additives and additives to be compatible with the fuel you're running. Running that fuel also reduces oil change interval.

Not to mention the cost of implementation of methanol setup between pump, injectors, oils, oils, oils is exponentially higher than $60 for a fill up of 100octane and 3,000mile oil change intervals.

As soon as we get all the information and sign the deal I'll let you all know more info.

93 is perfect for my little setup, don't think I'll be needing any race fuel anytime soon lol, but way cool for the guys pushin some serious power like u and Mike.

This should also be a cheap safeguard for anyone looking to push their setup, even just with some spirited driving.

Well i have never had any problems with the 93 at T&C. i run it in everything and no problems yet. And ive been runing it for over a year. The SS really likes race fuel mixed with 93.

ts4l wrote:

There is nothing wrong with 10% ethanol in the gas. By mandate in the next year or two all gas will have 10%.

I may soon have an alternative for everyone. We'll see how the meetings go. But I may have a new product for everyone to test out, and its already very well accepted by lots of Subie guys around the US.

Is it NOS energy drink? ... I keed I keed!
I might be interested in giving it a try.

ts4l wrote:

There is nothing wrong with 10% ethanol in the gas. By mandate in the next year or two all gas will have 10%.

I may soon have an alternative for everyone. We'll see how the meetings go. But I may have a new product for everyone to test out, and its already very well accepted by lots of Subie guys around the US.

Well this had better exclude race gas!

OT; I frieken love this site!!!!!! So many smart gear heads here!!

Back on topic, I also never ever ever had problems at T & C. I know I got worse gas mileage, but that is a given with higher octane ratings. worse gas mileage is worth the extra protection IMHO.

Its not like Octane booster, octane booster is usually never going to make any difference. I was waiting till I have all the details and can test it out in my car but it is very high concentrate race gas straight from a refinery. You would add something like 6 ounces to a tank, I don't recall the exact percentage right now. And it would get the octane up to about 106 octane. With a higher percentage you can get all the way to 116-118 I believe. However this is real race gas not some so called "Octane booster" that will only change burn rate. There are a lot of Subaru guys that use it as its cheaper than filling up on race gas and you can carry it in your trunk so you can go on road trips or fill up anywhere without searching for race gas. Its made by a well known company. I think we are meeting with them later this month at thier office in Arizona. I'll keep everyone posted and when I tell everyone what it is you can already find poeple using it all over that have dyno tested it to verify the octane bump.

Is it leaded?

The gas is Unleaded.

Back on topic, spark plugs look fine now. Must have just been because I have not changed them with this new build yet.

What kind of plugs are you running Mike? I know they are NGK's obviously but are they 2 step colder plugs?

BCPR7ES. Believe the stock WRX is a 6, I cannot keep all my car information sorted out. Think the RS was a 5. Too hard to remember at my old age.

Just so you know, NGK Spark plug numbers as they go down you are going hotter and as they go up they go colder.
Usually as far as part numbers go its opposite but NGK is a bit backwards in their ways, but they've never let me down thus far.

DigitalSpecV03 wrote:

Just so you know, NGK Spark plug numbers as they go down you are going hotter and as they go up they go colder.
Usually as far as part numbers go its opposite but NGK is a bit backwards in their ways, but they've never let me down thus far.

+1 I love my NGK's on my STis and even in my Quad!

You ever heard of the new plugs called "e3"? I put em in my specv last time just to get a review... not bad considering I came from NGK Iridiums, but i dont know about how they work in a boosted application though...

I use an E3 plug in my chopper



We've determined that it's the plug that works the best and gives the most power in these little 2 strokes

Personally I think the iridiums are a waste of money. I buy the cheap NGK for 99 cents a plug and never change them all year.

All the plugs i Have ever used the higher number is cooler! Weird I have never seen a plug the other way around.

Autolites are the other way around if I recall correctly...

Yeah, I run the 7s in the NGK. Work great and like Jason said you can change them all year without having to worry about cost. They are very cheap.

Stock WRX is a 6 BTW. Yay, I was right!!

Question for the spark plug gurus, how much of a difference would changingto spark plugswith a hotteror colder heat whatever affect an NA car?

You usually run hotter plugs on a NA if you have oil fouling problems and colder if you have boost... thats what Ive been told anyways

Usually you should stick with what you have until you make major changes. Things like boost that add more heat will possibly need a colder plug. But you want to be on as hot of a heat range as possible without detonation. There is no benefit from a plug that is too cold. You will just lose power and foul plugs quicker.