911mhawk

If you're running a tune and have heard they eat your plugs up quickly, I'll confirm. Last night I replaced the plugs and coils after 8,500 miles and the difference is night and day. At idle and under light throttle application or lift, the car is much much smoother.

Looking at my car service log and matching those dates with when a misfire code came up, shows I should have done them at 7k miles.

Not sure how my scenario would be similar to others with just a tune, but if your car is not running real smooth consider doing the plugs/coils. The car only threw misfire code 1 other time after clearing so you may be running less than optimal and not get any CEL either.

When it threw a code for the first time in November after logging just over 7k, I sent Kevin a message and he said "plug time". Looking back at our messages he'd said this would be the case with my set-up.
For reference, I'm running UMW K16 ZC turbos/tune/clutch/fuel.
This is the only code I've thrown since install and almost 9k miles under Kevin's guidance on parts/maintenance (shameless plug I feel is owed after some 3/4/5 pulls to make sure I wasn't under a placebo effect).

Best 3.5 hours spent on the car in a while.

jason952

What coils did you get?

fung0001

Long life plugs for new cars last at least 50,000 km
🤕

napoleon1981

Much longer than that. I replaced the iridium plugs at from my Honda at 100k. Still looked virtually new. Did not notice any change in running either.

I bought my 2003 X50 with 50k miles and still on original plugs. Engine ran fine, but I replaced them. These plugs were definitely worn, gap was huge, but the engine (without tune) ran surprisingly good.

NoogaSparrow

whoa... so this is 'normal' behavior?

What could the difference be, if the AFR is better on a re-tune? Is it due to more fuel (thus causing the more power) that is dirty-ing the plugs?

What is the Porsche recommendation on changing plugs?

Quadcammer

pretty ridiculous, but yes I was planning a 10k mile plug lifecycle.

Third-Reef

I would imagine that this has something to do with how much you get into it. Regardless of having a tune if you cruse easy freeway miles and stay out of the boost i would imaging the plugs would last much longer. But hey, who would do that.

Dock

^This.

993GT

fresh plugs are always nice
did you do coils at last plugs change? 7000-8500miles til misfire seems very short, unless primarily track...maybe initial plug gap was too large or faulty plug/coil? how did old plugs look?
I try to do plugs in my GT2 (WG's, fueling, straight pipe, EPL 91oct-track) at least every 20k km/12.5k miles (more often then not at 15km), but ended up putting on more miles than expected this season and ran the current set at ~25k km/15k mile without any misses(datalogged)...LOTS of WOT/track time.
Either way, never hurts to freshen up/PM early

911mhawk

These:

911mhawk

I did new coils last change and my initial gap was .034.
Lots of 100 octane and a dozen or so track days in 2016.
Track "days" are often a lunch broken into a few 20 minute sessions, or half day broken into 2-3 run groups per hour. Typically that's enough to get my fix as I'm lucky to be near a great track with many days available to run.

I also run Kevin's datalogger(25/sec sample rate) on all my track days to document engine run condition/watch out for possible concerns.

My commute has a nice 15 minute warm up period to the freeway, then ~20 minutes on freeway and a 10 minute cool down. Occasionally times may be halved and/or the commute extended because of this car.

This time plugs are closer to .032.
I didn't bother to check ending gap on used plugs yet.

Macster

With my stock 2003 Turbo by observing the boost display on the dash even on the freeway driving "easy" the engine once in a while makes boost, 0.1 to 0.2 bar. A bit of throttle to pass and the boost can go up even a bit higher.

A tune under the same driving conditions might have the engine making boost earlier or making more boost.

Also, a tune that delivers more HP/torque means the engine is making more heat and heat is a prime factor in plug life.

Also, the DME with its stock "tune" is intended to run the engine at just short of the onset of detonation. With a tune the engine could spend more time at this point and this works to shorten plug life.

Road King

Plugs should have been changed at the 30K service. 50K is a long time, perhaps your car wasn't driven very hard--mine wasn't as shown by the very gentle DME readout.

So, my car had plugs changed at the 30K service and ran great when stock, but I bought it with 44K and the subsequent tune exposed a bad coil and/or plug at around 46K miles, as confirmed by the misfire code. Guessing it was a coil since the plugs were only 16K miles and a few years old, vs. stock 14 year old original coils.

I had my local shop replace the plugs with GT2 spec and upgrade to the 997 coils shown above in this thread. No more missfires and the car runs great. I was hoping to get 15-20K miles out of the plugs, as that's several years of driving for me. But I have been running exclusively on 100 octane (with a custom Sambo tune) and perhaps the plugs won't last as long. Time will tell.

Carlo_Carrera

Exactly, it is the extra heat that does it.

fung0001

I understand that newer bmw set the working temp of engine a bit higher for better efficiency
still their plugs work fine for at least 50000km