[JetDriver]

Never weighed a platinum plug against an iridium one, but even if the platinum weighs 2 ounces less, I doubt they were being that OCD about weight. The car will weigh less when the pistons exit through the side of the block due to preignition as well. But seriously, there had to be a more scientific reason that came out of R&D as to why they chose Bosch Platinums. Maybe they just wanted to support a German company.

[Aronis]

Originally Posted by JetDriver

Never weighed a platinum plug against an iridium one, but even if the platinum weighs 2 ounces less, I doubt they were being that OCD about weight. The car will weigh less when the pistons exit through the side of the block due to preignition as well. But seriously, there had to be a more scientific reason that came out of R&D as to why they chose Bosch Platinums. Maybe they just wanted to support a German company.

I'd like to learn the reason, because it is an interesting topic.

A friend who tuned his 335 had a back and forth with which plug was best. Iridium or platinum, hotter, colder, it was an interesting discussion with the rational for each type and under what max boost. There's a lot of science to this stuff.......it is interesting.

Mike

[Autoregression]

Originally Posted by Aronis

I put them in a single PDF.

Sharing is Caring LOL.

Mike

Super helpful! Thank you!

[Autoregression]

Just finished up. Took me about 4.5 hours, but that includes doing the driver side twice (missed a coil connection and fired it up on seven cylinders).

If I do it again, I’ll do the coil packs just because they’re already out. It will probably take me 1/2 the time now that I know how all the connections fit together.

Plugs look good. The car has 43k, although no idea when these were last installed.

[pbonsalb]

I just redid mine at 45k. I had done them at around 26k so this was an early change but I run more boost and a little smaller gap of 0.024. I did vacuum the coil holes for whatever that is worth. The coils have boots that go over the holes, so there should not be anything down the holes.

My original coils seemed fine - no misfires even with raised boost, but I went ahead and changed them to the Dinan ones that claim to be stronger and cost less than stock. As is written above, it makes sense to change coils when changing plugs, if you are going to bother changing coils for any reason.

I did notice some greenish residue in several of the injector cavities on the driver’s side. Maybe this was from a leaking tank in the past or maybe from when I changed the tank about a year ago. I blew out any debris that would move with compressed air. Never had any issues.

[Aronis]

Fantastic, great to see others DIY....I have 52k, so will need to do plugs soon I guess. Last time the car told me at 25k that it was due. No message from the car yet. I have to figure out when I'll do the spark plugs. I don't think coils need to be changed routinely? I want to do oil and filter and replace front grill too.

Mike

[Maverik259]

Originally Posted by Aronis

Fantastic, great to see others DIY....I have 52k, so will need to do plugs soon I guess. Last time the car told me at 25k that it was due. No message from the car yet. I have to figure out when I'll do the spark plugs. I don't think coils need to be changed routinely? I want to do oil and filter and replace front grill too.

Mike

I wouldn’t worry about coils until at least the 3rd “normal” spark plug change which you seem to be on. Some changing them every 15-20 is a tad ludacris. Lol. Ran elevated boost on my N63 and changed coils at 80k miles just because I was do for plugs and didn’t want to go back in 10-20k miles later just for a bad coil. Was gonna do the Dinan ones but they were sold out. Went with eldor based on their solid rep before bmw swapped them to Bosch and many issues that followed.

[Rup91]

Anyone know stock gap on these bad boys? I bought 8 Bosch oem plugs but have been sitting for around a year. Just want to make sure I have the right gap before I go through all this work.

[Maverik259]

Originally Posted by Rup91

Anyone know stock gap on these bad boys? I bought 8 Bosch oem plugs but have been sitting for around a year. Just want to make sure I have the right gap before I go through all this work.

For under 15 psi you will want to gap your spark plugs 0.028" - 0.032". For higher boost you will want to gap your spark plugs 0.018" - 0.022".

If you experience break up under boost, the rule of thumb is decrease your spark plug gap by 0.005" increments at a time until the desired stable rpm gap is reached.

[Alan l.]

Something to keep in mind when doing spark plugs is to get a digital torque wrench so you know EXACTLY how much is needed. I believe for most BMW's is 22nm or about 17-18ft lbs without any lube (dry).

I've done plenty of plugs in the past and I've always just done it tight then another half turn. I did the same on the S63 but turns out it wasn't tight enough and caused weird idling sometimes. I bought a digital torque wrench and i was surprised just how many more turns it was able to go before it hit 22nm and it solved my weird sporadic rough idle that i've been chasing for months.

You really dont want to guess when it comes to this because if you over tighten and strip the threads its going to be a real bad day for you (new head = $$$$$)

[kujo813]

Originally Posted by Aronis

I can't find any videos on this for the F90. There are some for the prior model. Does not look that bad, but have to move a ton of stuff out of the way. Trying to decide to DIY or have dealer do it. 25k service.

Mike

Found this video the other day. Hope it helps.

[Aronis]

Originally Posted by kujo813

Found this video the other day. Hope it helps.

That link is on prior page LOL.

That guy does a nice job but the iPhone battery dies at the critical time, the driver's side LOL.

When I do mine I'll use three Go Pro's and capture it

Mike