Author Topic: How To: 2008 (GR) STI spark plug install  (Read 1323 times)

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Offline Sleeper

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How To: 2008 (GR) STI spark plug install
« on: March 30, 2009, 08:59:33 pm »
I swapped plugs today on my '08 STI from stock to 1-step colder NGK Iridium's. The rule of thumb is for every 50-100HP over stock, you should go 1-step colder plugs.

The part # for the NGK's is LFR7AIX. The stock number is NGK 2309.


The '08's are a bit of a pain in the assay once again because of the more cramped front end. The battery is in the way, as is the air pump and the hosing coming off of it.

Anyway... the how-to:

Before getting into it, get the easy stuff out of the way:
1) Remove battery.


2) Remove snorkel, air box, and elbow. If you have an aftermarket intake like I do, you can skip this step.

3) Identify the coil packs on each side that you need to remove to get access to the plugs.
Passenger side -



Driver side -



Removing coil packs:
Passenger side -
1) On the passenger side, get a 1/4" or 3/8" drive ratchet wrench with a 12mm short socket. Undo the two 12mm bolts - one for each coil pack.

2) Once loosened (you don't have to completely back out the bolts), pull the coil pack out. The rear coil pack needs to be turned 180* to remove it.

3) Unplug the two connectors (white for front, black for rear).

4) Set aside the two coil packs orienting them the way they came out of the engine.


Driver side -
1) On the driver side, unclamp the top hose off the air pump.


2) Pull the "hose" off the two outlets on the air pump, and pull it up out of the way.



3) Repeat steps 1-4 above.



Removing stock plugs:
1) Using a 5/8" spark plug socket, a 3/8" drive ratchet and an extension, remove the first plug.

2) Remove the next 3 using the tools listed above, but you may need to fiddle with different length extensions to get at the plugs. An easy way to do it is to get the socket/extension on the plug, then connect the ratchet wrench second.


Old plug:


Installing new plugs:
1) Put anti-seize on the threads of all four plugs.

2) To install, simply do the reverse of above. Torque them in hand tight, then complete torquing it to (IIRC) 15lb/ft - check the FSM for exact torque specs. If you don't have a torque wrench, tighten them with a ratchet until comfortably tight. If you overtighten, bad things happen... ie. broken plug jammed into your engine lol.

Finishing up:
1) Reinstall the coil packs, putting the correct connectors on the correct packs.

2) Reinstall the battery and intake (if applicable).

3) Call it a day.