1st off hats off to
DuSh for the constant out of box thinking, been hiding in the shadows reading.
Anyway, I'll be the owner of an F15 50i in the next few months it's just hard right now to find the color options I want with the miles and MSport.
Regarding the plugs after many hours of research I found out several things:
- We know that BMW uses a double platinum plug from the factory which is fine for stock applications
- Once we get to a Stage 2 tune we MUST change our plugs. If utilizing an iridium plug (97506) you will have more spark energy vs platinum. It is 6x harder, 8x stronger, and has a 700* higher melting point than platinum. Iridium plugs can last up to 25% longer than platinum.
- Iridium spark plugs feature a fine wire center electrode that is designed to conduct electrical energy better and increase firing efficiency which can reduce the required coil voltage by as much as 20-percent. That 20% difference can make or break your missfire issues. Not only do iridium’s properties reduce the ignition voltage requirement considerably they contribute to improving the spread of the flame front in the combustion chamber. Less voltage to fire = more spark energy = better VE
- Stock gap is 0.030" which is fine for stock boost levels but nowhere near sufficient for 20+psi. Stage 1 tune can get away with stock gap and stock plugs, but if the plugs have some miles on them you might get missfires. So even before you flash a stage 1 tune replace your plugs. If you feel like you will be going to a stage 2 tune anytime soon I would skip the stock replacement platinum plugs and jump to the NGK 97506 Iridiums gapped at 0.025". Which will be a sufficient gap up to the max 21.7psi on the stock TMAPs. If you get a custom tune that targets 24-26psi (obviosuly with the N20 3.5bar TMAPs) I would definietly close the gap some more to 0.023".
- Because iridium is costly, iridium spark plug manufacturers reduce the diameter of the center electrode to as little as 0.5mm. In addition to saving money, like I said the “fine wire” center electrode on iridium spark plugs increases firing efficiency.
- Some tuners claim that fine-wire plugs run “hotter” than normal plugs and that you should avoid fine-wire plugs especially in supercharged or turbocharged applications but facts support the exact opposite conclusion. As an example, the supercharged 2018 Dodge Hellcat—which makes 707 hp from its 6.2L Hemi—specs an iridium spark plug. If you want another example, the 350 hp Focus RS turbocharged four banger pushes as much as 25 psi of boost, which also employs a factory iridium plug. Also, if any of you guys come from the N54/N55 realm like me then you know the 97506 is the most run plug across the board for a reason.
https://www.oreillyauto.com/shop/b/i...d7/2015/bmw/x5