[Dawgz]

So I just got my DME Femto unlocked and im running the BM3 Stage 2 OTS 93 octane Multimap (with Flex fuel) - Will be doing a custom Ethanol map in the coming weeks.

The car is at 12K miles so I thought I would throw on some fresh gapped spark plugs. Gapped them to .022 as I did on my X3M.

Started with Cyl 6 first, such a pain with all the wiring above it - the X3M did not have all this as the M4 does.

Onto Cyl 5, it was not torqued down at all. When it took it out it looks totally different from the other 5 plugs, likely due to not being torqued down properly.

I change my spark plugs on these S58s every other oil change so I will monitor how Cyl 5 looks next time around. I read on here of someone who had a similar experience with Cyl 5's spark plug, but I cant find that thread / post any more.

Pic below showing all 6 spark plugs, starting with Cyl 1 at the far right, closeups of Spark plug from Cyl 5.

Installed the new plugs and went for a drive, it PULLS.

[SwankPeRFection]

Even if you drive it hard and abuse it, you should be able to squeeze at least 30k out of them. Not sure why you think it’s necessary every 10k, unless you’re getting misfired for some reason. Plugs don’t look fouled or anything. On 5 I’d be more worried about the oil residue at the top of the threads than anything else. Did you look in the plug channel to make sure you don’t have any oil seeping by any seals or anything. If that was happening though, you’d see some on the coil plug and top of the porcelain and I don’t see that. Whatever deposited it, it’s right at the plug opening. It’s weird that the rest of the threads are clean… never seen that where the top doesn’t have oil from seals but the first couple of threads do.

[vasillalov]

Even if the plugs don't look bad, the gap starts to change. As the gap increases, the ignition system would need more power to create a spark and as such it puts more stress on tge entire ignition system. In direct injection motors, this is even more critical because there are actually two or more spark events per cycle. If the plug gap gets too big, the coils will get overloaded and may go bad. If the coils survive, then resistors in the ECU will burn. Don't trust me, just look at the N54 cars. I have one and I am religious about changing plugs. They are the cheapest and easiest thing to replace. Coils and DME repairs are far more expensive.

On a direct injection turbo engine, I would change plugs ever 10K miles.

In other words, I fully support what the OP is doing and I encourage everyone to have a 10 to 15K interval for plug replacement.

[BB6]

So a few tuners have indicated the ignition system good enough on these G8X that there should not be a gap required. I have been running no gap on custom E50 tune for around 6k miles with no issue or breakup at all. I changed my plugs a couple times. I pulled the stock plugs out when I sent my DME to Femto in preparation for tuning and gapped new plugs to .025 for what everyone does custom tune. I ran those on OTS Stg2 E50 for about 2k miles waiting on tuner to get me a base stage custom to start calibrating. I uploaded his base map for custom tuning and did logs. He looked at my logs and I told him my plugs were at .025. He told me to swap them back to stock gap because that is what he has been running on his tunes with no issues. I then installed the 3rd set of plugs, logged. No issues so far at stock gap and I continue to get revisions from him with no breakup due to gap. I have about 8,700 miles on the car. I just got another revision pushing a little more boost and power so we will see how the plugs hold up and if there is breakup. Just info for you guys.

[SwankPeRFection]

The gap isn’t going to open up on an iridium plug in 10k miles, not enough to even put a dent in the performance or utilization of the coils. Lol

Unless you pull those plugs out and they look much darker and abused, you’re not going to have a measurable gap increase, especially on these plugs. A lot of the misfires that’ll happen or other issues will be due to misgapped plugs from the beginning or if you’ve got a tune or other issue fouling the plugs like oil blowby or IC core coolant leak. The OP just needs to keep an eye on the one that’s got some oil residue at the top of the threads, that’s the only wacky one from the looks of it.

.028 is usually a good gap to run on FI engines like these and be good with a smooth idle and no misfires up top.

[Dawgz]

Originally Posted by SwankPeRFection

Even if you drive it hard and abuse it, you should be able to squeeze at least 30k out of them. Not sure why you think it’s necessary every 10k, unless you’re getting misfired for some reason. Plugs don’t look fouled or anything. On 5 I’d be more worried about the oil residue at the top of the threads than anything else. Did you look in the plug channel to make sure you don’t have any oil seeping by any seals or anything. If that was happening though, you’d see some on the coil plug and top of the porcelain and I don’t see that. Whatever deposited it, it’s right at the plug opening. It’s weird that the rest of the threads are clean… never seen that where the top doesn’t have oil from seals but the first couple of threads do.

Ya channel was fine. It just looks like it seeped in somehow because it wasnt torqued down. rest of the Spark plug tube itself was clean.

When these are tuned, they eat spark plugs - they are fine but as they wear the gap expands. Its good to keep fresh plugs with a tight .022 gap especially when this car will be going to the track often.

In my tuned X3M you could tell it needed a plug change every 5-7K miles as it would have a slight skip at idle. Once the plug was changed it would be all smooth again. Its cheap insurance to keep the car running at its best; with FCPEuro it also costs little to nothing as the replacements are free.

[vasillalov]

Originally Posted by SwankPeRFection

The gap isn’t going to open up on an iridium plug in 10k miles, not enough to even put a dent in the performance or utilization of the coils. Lol

I will show you my iridium 3 prong plugs from my N54 after 10K miles and you will "sing a different song".

Respectfully, you have no idea what you are talking about.

[SE7EN335]

Originally Posted by SwankPeRFection

The gap isn’t going to open up on an iridium plug in 10k miles, not enough to even put a dent in the performance or utilization of the coils. Lol

Unless you pull those plugs out and they look much darker and abused, you’re not going to have a measurable gap increase, especially on these plugs. A lot of the misfires that’ll happen or other issues will be due to misgapped plugs from the beginning or if you’ve got a tune or other issue fouling the plugs like oil blowby or IC core coolant leak. The OP just needs to keep an eye on the one that’s got some oil residue at the top of the threads, that’s the only wacky one from the looks of it.

.028 is usually a good gap to run on FI engines like these and be good with a smooth idle and no misfires up top.

Depends on what tune is on the car. I've seen S55 OE Bosch plugs go from 0.020" to 0.030" within 15k kms on a stock turbo custom 98 Ron tune. So i'd imagine it is the same for the s58. On a stock tune, there might not a measurable difference within 10k miles but if you start tuning the car (especially custom) it's better to gap them and shorten the spark plug change intervals

[markoz28]

Been racing cars for 26 years. It is ideal to change plugs more often than factory recommended. If they say 30k then I would change every 15k. As far as gapping, that depends on your tuner. I have heard most say gap to 22 with some saying stick with 28. If you are unsure I’d split hairs here and aim for 25. My tuner is requesting 22 so that’s what I’ll do.

[TopJimmy]

How oily were the plug holes? I see black residue at the top of your threads near the washer on #2.

I changed my factory plugs at 3300mi to set gaps for my tune and found my #1 plug hole had a little oil in it. A few other plugs loosened very easily. I torque my plugs to 25Nm (not 23Nm). The oily plug has not returned.

[SwankPeRFection]

Originally Posted by vasillalov

I will show you my iridium 3 prong plugs from my N54 after 10K miles and you will "sing a different song".

Respectfully, you have no idea what you are talking about.

Did you just say N54?… OK. How much oil and fuel (rich) contamination do you have on those? Yes, please do show them. Willing to be they’re not as clean as the OP’s. Be sure to also list the tune and mods for it, specifically who did the tune… that makes a big difference.

[g80.py]

How often do you all recommend for a stock baby

[Dawgz]

Originally Posted by g80.py

How often do you all recommend for a stock baby

Probably 15k or whenever you notice it missing at idle.

[Dawgz]

Originally Posted by TopJimmy

How oily were the plug holes? I see black residue at the top of your threads near the washer on #2.

I changed my factory plugs at 3300mi to set gaps for my tune and found my #1 plug hole had a little oil in it. A few other plugs loosened very easily. I torque my plugs to 25Nm (not 23Nm). The oily plug has not returned.

Cyl 5 Plug hole wasn't oily at all, slight residue right at the beginning of the thread but that's about it. All of the rest were clean.

And good to hear it didn't return!

I ran a log yesterday on my stage 2 tune full throttle from 2500rpm in third gear to top of 7k rpm shifting into fourth and ringing that to 7k as well.

Timing is all good across the board.

Ready for ethanol tune!

[SwankPeRFection]

Originally Posted by SE7EN335

Depends on what tune is on the car. I've seen S55 OE Bosch plugs go from 0.020" to 0.030" within 15k kms on a stock turbo custom 98 Ron tune. So i'd imagine it is the same for the s58. On a stock tune, there might not a measurable difference within 10k miles but if you start tuning the car (especially custom) it's better to gap them and shorten the spark plug change intervals

Absolutely, it depends on the tune and the engine also. Bosch plats are really horrible and giving up in that 10-15k mile range, especially if you’re on the rich side of things. Older versions of this engine and the B58 older derivatives had their own set of issues contributing to plug abuse, some of which do not carry over into the new S58 as much in my opinion.

[Dawgz]

Originally Posted by TopJimmy

How oily were the plug holes? I see black residue at the top of your threads near the washer on #2.

I changed my factory plugs at 3300mi to set gaps for my tune and found my #1 plug hole had a little oil in it. A few other plugs loosened very easily. I torque my plugs to 25Nm (not 23Nm). The oily plug has not returned.

Went out to check plug #2 that you mentioned, seems to be ok even under the washer.

[SwankPeRFection]

Originally Posted by Dawgz

Went out to check plug #2 that you mentioned, seems to be ok even under the washer.

I think he was talking about #5 and didn’t realize it was 5 and not 2.

[Forzanerazzurri]

Sorry the service interval for plugs on these cars per BMW is 15,0000 miles? Huh?

[vasillalov]

Originally Posted by SwankPeRFection

Did you just say N54?… OK. How much oil and fuel (rich) contamination do you have on those? Yes, please do show them. Willing to be they’re not as clean as the OP’s. Be sure to also list the tune and mods for it, specifically who did the tune… that makes a big difference.

Zero! Unlike most shit tuned and maintained N54s, mine is excellent!

[SE7EN335]

Originally Posted by Forzanerazzurri

Sorry the service interval for plugs on these cars per BMW is 15,0000 miles? Huh?

30K miles for stock tune.

22.5K miles for OTS maps on pump gas.

15K miles for custom tunes on anything above e60.

[Forzanerazzurri]

Originally Posted by SE7EN335

30K miles for stock tune.

22.5K miles for OTS maps on pump gas.

15K miles for custom tunes on anything above e60.

Much appreciated