Kelsey

Anyone change the plugs in their GT4 yet? Just curious as I am coming up to the 4 year mark. Any DIY information would be appreciated. Thanks

Davin

In for this too, my car only has 2700 miles. I felt like it’s not necessary to do it but I’m curious of what you guys think

jmartpr

I just did it at 24K miles......a real PITA to get the front coils/plugs out. You will need several extension and the wobble/flexible unions/extensions.
Once the car is lifted it can be done in 1-2 hours taking your time. Easy Do it your self job...just a bit hard to reach if you don't have the proper tools.
The Porsche plugs come pre-gap from the factory. Please note the torque on these 24 ftlb for new ones....19 ftlb if they are used/already been torqued.

neanicu

I'm pretty sure there's no service interval based on time for spark plugs. It wouldn't make sense IMO. I believe it's mileage only. And even though in most regular engines the spark plug interval that is mileage related has increased significantly over the years due to higher quality metal used(like iridium),Porsche and other manufacturers that produce high performance engines have actually reduced the interval! I suppose it's due to the fact these engines are wearing the spark plugs a lot faster. So,I'll bet the service interval is probably something like every 25-30K miles...
Just tell your technician or if you DIY,to use a tiny bit of anti-seize on the threads,that way they will never seize in the block no matter how long they're in there. Do not listen to what the spark plug manufacturer recommends...I've seen them seized too many times. Also,if you use anti-seize reduce the recommended torque 5-6 pounds so you don't over torque them.

Kelsey

Thanks for the information. I had a 2007 Boxster 987.1 and did them. Wasn’t too bad except for the driver side front. Glad to hear that the GT4 will not be that difficult. Thanks

jmartpr

I also second the use of anti-seize when installing new...did this on mine and no problems, Just don't go crazy with the stuff.
Backing off 3-4 ftlb on the torque is also advisable as it's different when installing dry threads vs threads with any kind of lube/compound..
Porsche is classifying worldwide markets into A. B and C and based on that some components do require different maintenance intervals.
According to the Workshop Manual market A is 48K miles, Market B is 40K miles and Market C is 12K miles.....pretty sure the US falls either A or B depending on where you live.
Anyway, I think doing them at the 20K-25K mile interval is Ok and not too expensive if you do it yourself.

Switchfoot614

I strongly suggest using only Porsche approved plugs and not the Bosch version for 2 reasons. 1. based on personal experience with my 997 (there was a long thread in that forum if you're up for a good read) and 2 based upon a close quality auditor friend who audited Bosch. I'll summarize the findings. When interviewing the QC technician performing final inspection of spark plugs, the auditor noticed 4 bins where the inspected parts were sorted after testing. A, B, C, and D. The auditor asked what the difference was. QC quickly advised that group A's are 100% within tolerance for all tests and are the only ones who pass the Porsche acceptance criteria. Group B's are acceptable to other OEM auto manufacturer's and will be labeled as their respective manufacturer. Group C will go into a Bosch box and be sold to retailers/wholesalers and of course Group D fail to meet the least restrictive acceptance criteria. The 997 thread and my experience summarize that Group C plugs may or may not alleviate a slight miss at idle and/or that off idle hesitation even when properly gapped and torqued (no other faulty components in system). For what it's worth, this auditor friend of mine is a huge car nut and a master in his field so he has more than earned my respect over the years. In my industry, acceptance criteria is everything and to know that Porsche actually defines and audits their suppliers means something to me.

RA

CaymanCarver

I'm curious to know if Bosch QC's EVERY SINGLE spark plug they make.
Could you check back with your friend on that point?

I'm assuming the answer is No, which would mean there is a subset of "A Group" plugs that get distributed to OEM and retailer/wholesalers and are sold at a significant discount.
This might also explain why the Porsche Genuine label demands such a high price. Not that many plugs actually get QC'd.

Viperguy324

I would think they do. I know NGK does.

CaymanCarver

K' I did some searching around and found this ad/document from Bosch

In the doc it states:
This is inconsistent with the info provided by SwitchFoot indicating they distribute Spark Plugs of four different Quality Grades.
Either they're all of the same quality or they're not.

More data would be interesting:

• How many Spark Plugs do they manufacture per day / week / month / year?
• Is the QC process and test procedure automated or manual?
• How many people are employed that perform the QC procedure and sorting process?
• What exactly is the criteria for the separation and sorting?
• Are the Spark Plug packages coded in some way to indicate the particular Quality Grade.

Switchfoot614

Just my .02 based on a personal source. There is a thread in the 997 forum regarding spark plugs with plenty of opinions.

CaymanCarver

Thanks Switchfoot, to me its kind of anecdotal. Its an opinion from someone on the interwebs who knows this other guy etc..

I mean no offense, I'm a data guy.
I need hard specs. like you mentioned it might be a simple matter of an ohm reading from the contact tip down to the electrode? Or an Impedance test? Ground separation verification?

I can do my own testing and would love to see how the $7 Bosch Spark Plug compares to the "Grade-A" units.
I'm gonna see what kind of information I can get directly from Bosch.

But my gut feeling is its just the standard Porsche brand name mark up.
I called my local dealer and got a quote for the Spark Plug & Coil Pack change at $1300 plus another $115 if they replaced the Coil Pack fastener screws. $115 for six screws (including labor).
I got new Genuine Porsche Coil Pack fastener screws from a Porsche Dealer on-Line store for .63 cents each. I've saved ~$1K buying the Genuine Porsche parts online and doing the job myself.
I know its not an easy job and the approach on extracting the old plugs can take the most time / be the hardest part.
i.e. work with the engine warm/hot, use some penetrating oil.. let it sit.. then work the plug back and forth, repeat etc.

So I don't think the $1300 Dealer fee is entirely out of bounds. It could easily take them 1.5 - 2 hours per side of the engine to complete the job. 3 - 4 hours of labor for a Porsche Mechanic ain't cheap.

Just for fun I'll read through that thread on the 997 forum.

KOTYKB

How many of you are getting your spark plugs replaced at the four year mark? I've been getting annual oil change and brake flushes done but spark plugs at 9,500 miles seems unnecessary for $1,300

RolloGigolo

I did it! Didn't want to but figured what the heck

trkshoe

$1300... for plugs?
Indy shops are your friend :-)
It may be a drive for you, but I've used these guys a ton, and trust them - https://www.sublimesilverlake.com/