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Old 05-08-2008, 02:56 PM   #1
Scooby Specialist
Member#: 23894
Join Date: Sep 2002
Chapter/Region: MAIC
Location: Central, PA
'07 3.2L Audi A4

Default Help me read my plugs

Ok so I think I have some work to do as far as tuning, but I think I'm really close. Please feel free to prove me wrong.

Driver-side Front Plug 1

Driver-side Front Plug 2

Driver-side Rear Plug 1

Driver-side Rear Plug 2

I'm not 100% on which is cyl # 1, 2, 3, or 4 so I labeled them from where they came. I've drawn out all the plugs and the ones on the passenger side mirror these to a point that I could not tell where they came from without the label I put on them when I pulled them...

From what I know of plugs, it looks like I'm running a bit too advanced in the mid-high load area (above 1.60g/rev) and getting some detonation, but my IAM is staying at 16 except for the initial maybe 150-250 miles where it was being pulled to 12 because of over-zealous timing. Ever since then (pulled 3 degrees base timing in the areas IAM fell) its never moved from 16.

AFR is really smooth and rock solid where I want it. 11.5-11.6 on the wideband at WOT. my fuel map is dead on with what I'm seeing on the WB.

Now for the list that will help you people help me.

oh and BTW there is 4800 miles on these plugs.

2.5 STi shortblock, P&P WRX heads
Plugs are NGK iridium in the stock heat range
Perrin fuel rails (stock FPR (43psi @ idle))
Stock modified injectors (tested at 810cc)
Walbro fuel pump
Stock but brand new turbo.
FMIC, Turbo XS short intake

things I don't think matter but are connected to the engine in some form:
Fidanza flywheel, ACT HD clutch, Koyo radiator
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Last edited by jackansi; 05-08-2008 at 03:02 PM.
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Old 05-08-2008, 03:15 PM   #2
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Join Date: Nov 2000
Chapter/Region: MAIC
Location: Pittsburgh, PA
2000 2.5RS


Did you pull the plugs immediately after a WOT run?

BTW if you are standing in front of the car, looking into the engine bay, the numbers are as follows:

3 4
1 2

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Old 05-08-2008, 03:40 PM   #3
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Chapter/Region: MAIC
Location: Central, PA
'07 3.2L Audi A4


Not immediately, I mean I shut the car off almost immediately (< 3 seconds after), but I let it cool down before I pulled them.

So I guess that makes the first two pictures from cyl 2 and the second two from cyl 4. 1 looked exactly like 2 and 3 looked exactly like 4. No joke, exactly..
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Old 05-08-2008, 06:03 PM   #4
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Join Date: Oct 2002
Chapter/Region: NWIC
Location: Portland, Oregon
2003 Sleeved 2.5
Oil Dry Sump Goodness


They look pretty good to me, a little soot, clean electrode great looking plugs for close to 5000 miles.

What are the specks, it's hard to tell in the photo's even zoomed in. If it's cooked soot then no issue, if they look metalic then it could be piston splatter from det but I doubt it. Those plugs look in very good shape, nice tune!
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Old 05-10-2008, 07:11 PM   #5
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09 sti09&00gc8


mick is saying right, it couldnt give an exact decision from the pictures but maybe there is some det in the engine especially it seems in the first picture. shape is good there isnt any overheating but a bit detonation might be appeared in my point of view.
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Old 05-11-2008, 02:54 PM   #6
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Your first picture really looks like detonation to me. The burn on the plugs are nice, but that sure looks like piston splatter.

It actually looks like it was recent because of the coloration around it but not on the splatter.

I could be wrong though...

Just my .02
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Old 05-11-2008, 06:04 PM   #7
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Join Date: Apr 2004
Location: Bend, OR
2011 WRX


Anytime I see shiny "salt" on a plug like that I get nervous. Get out a good loupe and make sure that isn't aluminum. The plug color (assuming you did a good WOT chop) is either perfect, or a lttle lean. Either way, check out that salt - it would concern me.
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Old 05-11-2008, 06:45 PM   #8
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2002 Impreza WRX


Hard to say with certainty, the speckles on the plugs in the pictures in most cases do not look like detonation spots. If on close examination they look like perfect little balls of bright shiny aluminum then it would be detonation, but the material looks more like an ash deposit.

Have you run leaded fuel in the engine? The material at the base of the ground electrode almost looks like lead build up, or the ash you see from some brands of oil. If that is the case you look generally okay although I think the heat range on the plugs is a bit one step too warm for my taste, as you have heat discoloration well back on the ground electrode. I have never run the iridium plugs so am not sure if they show heat on the ground electrode like most common plugs, but you might want to go one step colder if you can find them in that plug.

Other than that they do not look too bad from the outside.
To tell any more you need to hacksaw off the threaded part at the base and look at the base of the porcelain and the mixture discoloration down there deep inside the plug to know for sure where you are at. The soot build up on the nose of the shell looks good on all of them, your rear two plugs have a bit more soot on the shell than the front plugs but that is not a bad thing for our engine in my opinion.

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Old 05-12-2008, 12:51 PM   #9
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'07 3.2L Audi A4


After pulling the driver-side front again and pulling the specks off with some clear tape, or rather trying, they don't seem to be made of metal. They kinda disintegrated like they were ash. Under magnification they didn't have any aspects of metal.

A metal detector didn't even twitch at the tape, but even at its highest sensativity I'm not sure there was enough material to call that conclusive.

Thanks to everyone so far. I really appreciate the eyes.
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Old 08-19-2008, 02:34 PM   #10
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'07 3.2L Audi A4


Back again after 12K miles. This is after a WOT run through two gears (2-3), same road, same outside temp. Changes since first pictures:

1.5 degrees less base timing in areas that I felt were "too close for comfort" 1.15/g @ 2800 through 1.7/g @5600. A slight enrichment of .09 from 1.20/g @ 3100rpm on up.

I have a funny white deposit on #2.

1. Driver-side Front Cyl #2

2. Driver-side Front Cyl #2

Just weirded me out. I don't think I have anything critical to worry about, but backup on that would be great

Here are the rest, laid out just like they are in the engine (but not indexed):

Above from front of car

Above from front of car

Looking at driver's side plugs from passenger's side

Looking at passenger's side plugs from driver's side

These are out and one step colder went in. I was getting weird knock during transistions from cruise to passing in the 1.15 -> 1.45 load range especially after a climb up a slope. The colder plugs seemed to have cured that as I had hoped.

I did another run WOT (2-3) run and they looked brand new still so I'll be leaving them in till the next day with similar conditions.

Last edited by jackansi; 08-19-2008 at 02:40 PM.
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Old 09-04-2008, 06:19 AM   #11
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2004 STi
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+1 for someone using the right setting on the camera!!!
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