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Discussion Starter #1 (Edited)
Hi guys,
I pulled my valve cover today on my '07 Exige S (supercharged) for cam shaft inspection and I pulled all spark plugs.
They are the NGK Iridium's. Does this look normal or does it look lean on a boosted car? Very grey.

Thanks.
Henry
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I agree it looks lean. I suggest you take a look at the top of your pistons with a boroscope.

What relevant mods do you have (intake, SC pulley, tune, exhaust, head, fuel pump, injectors...)? What octane gas?

-Ed


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Ideally, you want color of cardboard box.

When I had to tune two sets on Webers, I ran to redline, turned engine off, coasted to stop to check mixture at high output.

You didn't spend a lot of time idling before pulling those plugs did you?

Are the plugs the correct # (heat range) for your car? Factory supercharger?
 

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Oh, do you torque your plugs and slather the tubes in dielectric grease? 2nd part more for newbies....
 

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Discussion Starter #8
While you have the valve cover off, have you checked the VVT lift bolts?
No I have not. Sounds like they should be replaced with a newer style.
Suggestions on where to source them? Thanks, Henry
 

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Discussion Starter #9
Oh, do you torque your plugs and slather the tubes in dielectric grease? 2nd part more for newbies....
No and No. Do you know the torque spec? And what's the rational for the dielectric grease?
 

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Discussion Starter #10
I agree it looks lean. I suggest you take a look at the top of your pistons with a boroscope.

What relevant mods do you have (intake, SC pulley, tune, exhaust, head, fuel pump, injectors...)? What octane gas?

-Ed


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Intake Side Mods
1. BOE Bosch EV14 Injectors
2. Radium Fuel Rail
3. Stock SC, but 3.10" pulley
4. NGK Iridium plugs from BOE (NGK BKR7-EIX)
5. I have not done the BOE Torque 300 tune yet (almost ready). When I bought the car it came with some type of tune on it (no idea whose) since the cam switch RPM point is at 5200rpm's
6. WALBRO pump is in the garage but has not been installed yet.

Exhaust Side Mods
1. BOE DMC Ultimate Header & Sport CAT
2. Larini Club Sport muffler

93 octane is fairly guaranteed here in New England.
 

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You can look up tq spec.

To prevent arcing of spark to cylinder head.

Get a frigging TQ wrench and use it for plugs, wheels, etc. Give your car what it merits/needs.

g
 

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Contact BOE by email and ask them for plug recommendation after sending above list of mods and photo.
 

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No I have not. Sounds like they should be replaced with a newer style.
Suggestions on where to source them? Thanks, Henry
Your local Toyota dealer parts counter, online Toyota OEM suppliers, Monkey Wrench Racing should all provide the updated part when ordering.
 

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Those seem like more expensive options compared to parts stores. Yes, there are only 4 plugs, but Henry may also need dielectric grease.....
 

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Well it is like a blast from the past! The dielectric grease slathered over all parts of the injector coil prevents arcing to the plug tubes. There is really only a mm gap. If any moisture gets in there then you will throw p1701 codes a misfire due to arcing. Just good practice but a bit messy. I run 1 step colder Denso IR IK22 plugs with the extra boost supplied. Yes there is propensity to foul them but safer, It does appear you are running a bit lean from the pic. If installing new plugs follow the manufacturer's recommendation for torque it is on the spark plug box. For reusing plugs that have the washer collapsed you need less torque. 15 ft/lbs it what I have used in the past but maybe someone with more knowledge can chime in. Also with higher boost from smaller pulley the gap may need to be slightly smaller.
 
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Get the lift bolts and valve cover gasket and spark plug tube insulators (basically rubber washer) from toyota. If you search my old posts I showed pics of part numbers.
 

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Hi guys,
I pulled my valve cover today on my '07 Exige S (supercharged) for cam shaft inspection and I pulled all spark plugs.
They are the NGK Iridium's. Does this look normal or does it look lean on a boosted car? Very grey.

Thanks.
Henry View attachment 1261852
Why not get a wideband O2? No more guessing.

IMHO, any modified car should have a wideband. I've learned the hard way.

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Discussion Starter #19
@ScottH83 - Sounds like that's the best bet for ongoing monitoring.Figuring out how to wire in the gauge and O2 would be the hard part.

Thanks,
Henry
 
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