Plugs (95770 v. 97506), gaps, and the N54

[pdxbimmertech]

Just wanted to add to this spark plug thread that NGK/OE isn't the only option these days for the N20 plugs. I have a set of Bosch ZR5TPP330 sitting here waiting to go in. One of the local parts suppliers we use at my work had them for around $10 each which is good considering the OE N20 plugs MSRP is close to $25 each. No experience using them but always good to have options when shopping for parts. Looking online now it looks like most places are out of stock on these at the moment but was curious if anyone on here has tried them yet?

 

[matreyia]

Just to be sure I understand this correctly... if your coils can dish it out... you should gap largest as possible for what benefits vs. smaller gaps???

Fuel efficiency, power, or both?

 

[fmorelli]

Okay ... here is what they sent. I'm trying to get NGK to confirm my best shot at it, which uses the second chart (heading, I T R 4 A 15). Note @doublespaces the "D" is special code that you were dancing around earlier - maybe you know what that means. Please someone run through this and critique:

SILZKBR8D8S
S - Square Tip Type
I - Premium Iridium
L - Long Reach
Z - Extended Projection
KB - Thread: 12.Ø, Reach: 19.0mm, Seat Type: Gasket, Hex: Bi-Hex 14mm
R - Resistor
8 - Heat Index (from 2-11, hot to cold)
D - Special code (we don't know what it means, but seems reach related)
8 - 0.8mm gap (0.030" - not listed in chart but deduced from other numbers)
S - Special Gasket

Filippo

 

[RSL]

EDIT: cleaning this up to avoid confusion, should not have included B58 info. Too many numbers, letters, motors and only looked them up to compare against the S55 plugs.

Have the N55 and S55 plugs converged to a single part number from NGK?

Not that I see anywhere. M OE plugs might change to NGK on S58 though and could explain why OE Bosch S55 plugs are being unloaded dirt cheap now to reduce inventory levels. OE S55, including M4 GTS, is Bosch for the latest builds that I can find. Aftermarket-wise, N20, N54, B58 (EDIT: those were N55, not B58), S55 people are using the generic 97506 NGK plugs as "upgrades".

B58: SILZKGR8B8S (NGK P/N 94201, BMW P/N 12120040551)
N20: SILZKBR8D8S (NGK P/N 97506, BMW P/N 12120039664)

The bolded letters appear to correspond to the ground strap design.

Spent a bit more time on the NGK numbering system over breakfast this morning - NGK lists 4 numbering systems, none which correspond to the Iridium IX plugs we are talking about. Unfortunately NGK's product web site doesn't even provide all the parameter information for the SILZKBR8D8S.

I plan to call them today and ask for the numbering system reference for this plug set.

Filippo

Directly off NGK's site. Only differences between B and D in these descriptions are the ground electrode tip design.

That brings us to the Bosch OE S55 plugs....

BMW P/N 12120039634
Bosch P/N ZMR5TPP330

Z = M12x1.25
M = Motorsport
R = With interference suppression resistor
5 = heat range (Bosch runs opposite NGK, lower numbers are colder plugs on Bosch)
T = 26.5mm reach (non-tapered seat)
PP = double platinum or a new unlisted design, but this index refers to electrode construction material
330 = unlisted special design, but likely indicates ground electrode construction/materials

Since they were brought up, N55 OE Bosch:

BMW P/N 12120037582
Bosch P/N ZR5TPP33S

Compared to S55, no "Motorsport" designation and S special design instead of 0, what those indicate.

Potentially interesting point: NGK has a cross-reference for N55 plugs (97506s), but NO plugs listed at all for S55.

 

[RSL]

Just wanted to add to this spark plug thread that NGK/OE isn't the only option these days for the N20 plugs. I have a set of Bosch ZR5TPP330 sitting here waiting to go in. One of the local parts suppliers we use at my work had them for around $10 each which is good considering the OE N20 plugs MSRP is close to $25 each. No experience using them but always good to have options when shopping for parts. Looking online now it looks like most places are out of stock on these at the moment but was curious if anyone on here has tried them yet?

ZMR or ZR? Been using the OE S55 plugs since 2015 and are the best plugs I've ever tried, which I've been trying to elaborate for 3 pages

Edit: I see on the Bosch P/N now, those are OE N55 plugs. I'm referring to the S55 OE plugs.

Just to be sure I understand this correctly... if your coils can dish it out... you should gap largest as possible for what benefits vs. smaller gaps???

Fuel efficiency, power, or both?

Yes, for all reasons.

1mm gap = .039", the common .018-22" gaps are 0.46-0.56mm or less than half of the minimum shown on this chart. It impacts flame worse at leaner lambda.

 

[fmorelli]

Let me just say this, for anyone else looking at the naming conventions - using the tables to decipher an actual NGK part number is no easy feat. Honestly they are pretty poorly constructed. It is unclear where the part number parses. So if you happen to be looking at the tables and are scratching your head, know you aren't alone.

Filippo

 

[RSL]

Let me just say this, for anyone else looking at the naming conventions - using the tables to decipher an actual NGK part number is no easy feat. Honestly they are pretty poorly constructed. It is unclear where the part number parses. So if you happen to be looking at the tables and are scratching your head, know you aren't alone.

Filippo

Agreed, not sure how manufacturers even keep up with them and some probably don't or they haven't trickled on to the web yet. Newest Bosch decoders I can find are years old.

Out of sheer boredom and to get a slew of numbers straightened out in my head (data from RealOEM):

- Several plug changes in a short span on N20s and all revolve around our favorite 3rd from last character.
- M235i looks like it was switched from Bosch N55 plugs to NGK N20 plugs at some point.
- S55 plugs are also on the M2 and X4 M40i, which are N55 motors.
- NGK site product look up lists no NGK cross-references/parts for either N54 or S55 at all.

 

[matreyia]

Update...today at lunch I started the car at gap .030 NGK 95770 and it sent a MIL and stumbled and misfired. Service engine light came on.

Turned off and restarted and went away.

So it appears that either the BL coils are degrading or the gap is not kosher for long term.

Will carry second set of NGK at
.026 for backup. Thursday will try stock Bosch BMW 3 prongs and see if there is a difference in power and mpg.

 

[fmorelli]

Out of sheer boredom and to get a slew of numbers straightened out in my head (data from RealOEM)

You should be bored more often. Thanks! From this table on the ... N20

I think it is deeper than what you show. For example 12120038704 also maps to the E89 28i (N20). Let's keep going: realoem says 12120038704 is, as you say, the SILZKBR8B8S. It also says that it is currently superseded by 12120039664 which realoem states is, SILZKBR8D8S. Ironically there was an interim supercession of 12120038704 which was 12120038896, that mapped to SILZKBR8C8S. So it went B->C->D.

What I find interesting about that that I thought that letter might refer to some aspect of the reach, but likely not as they would not have changed that relative to the combustion chamber, I would imagine. I believe that length is more likely specified by the 5-6 letters, KB, which map to a 19.0mm reach.

I would be curious to see an exposed head show a stock N54 plug, NGK 95770, and NGK N20 plug (any of the above) and 97506 relative to the injector tip.

Filippo

 

[Rob09msport]

Update...today at lunch I started the car at gap .030 NGK 95770 and it sent a MIL and stumbled and misfired. Service engine light came on.

Turned off and restarted and went away.

So it appears that either the BL coils are degrading or the gap is not kosher for long term.

Will carry second set of NGK at
.026 for backup. Thursday will try stock Bosch BMW 3 prongs and see if there is a difference in power and mpg.

Are they bl coils or bl by fillipo coils?
Edit to prevent misrepresentation of anyone.
Was joking but am referring to the technical post highlighting how to properly install and modify the bl kit not any product being sold by just way to have the existing bl kit function properly.

 

[fmorelli]

Out of the 3DM cars, we've now had two wiring harness failures on the BL coil setup. I'm not talking about crumbling connectors, rather harness crimps being weak and failing. Misfire on the cylinder that has the bad crimp and 2DED as the DME is pissed about electronic reality.

Trust me I want no association to this setup. PR looking better and better every day.

Filippo

 

[matreyia]

Are they bl coils or bl by fillipo coils?

Non-modified BL coils.
Just installed the stock bmw n54 triple prong spark plugs and car runs smooth and stable. Feels more powerful than the .030 NGK plugs. Will see how long they last.

So why do they say one step colder for each 100hp increase? Are these stock plugs going to go kablooey soon because of my power level increase and the BL coil voltage?

 

[Jeffman]

Update...today at lunch I started the car at gap .030 NGK 95770 and it sent a MIL and stumbled and misfired. Service engine light came on.

Turned off and restarted and went away.

So it appears that either the BL coils are degrading or the gap is not kosher for long term.

Will carry second set of NGK at
.026 for backup. Thursday will try stock Bosch BMW 3 prongs and see if there is a difference in power and mpg.

Interesting. I’m wondering whether your experience suggests some kind of spark / dwell adaptation learning that the DME undergoes. If so then jumping from .022” to .030” gap could cause the misfires and MIL you experienced.

 

[matreyia]

Interesting. I’m wondering whether your experience suggests some kind of spark / dwell adaptation learning that the DME undergoes. If so then jumping from .022” to .030” gap could cause the misfires and MIL you experienced.

If that were the case, it would have misfired last week when I installed them.

 

[Jeffman]

If that were the case, it would have misfired last week when I installed them.

Understood. Thought you just installed them today.

 

[RSL]

You should be bored more often. Thanks! From this table on the ... N20

View attachment 13768

I think it is deeper than what you show. For example 12120038704 also maps to the E89 28i (N20). Let's keep going: realoem says 12120038704 is, as you say, the SILZKBR8B8S. It also says that it is currently superseded by 12120039664 which realoem states is, SILZKBR8D8S. Ironically there was an interim supercession of 12120038704 which was 12120038896, that mapped to SILZKBR8C8S. So it went B->C->D.

What I find interesting about that that I thought that letter might refer to some aspect of the reach, but likely not as they would not have changed that relative to the combustion chamber, I would imagine. I believe that length is more likely specified by the 5-6 letters, KB, which map to a 19.0mm reach.

I would be curious to see an exposed head show a stock N54 plug, NGK 95770, and NGK N20 plug (any of the above) and 97506 relative to the injector tip.

Filippo

I'll dig, but I know for a fact there are cutaway long blocks with plugs installed. I was surprised about how not straight the coils go in when I first saw them. Firing depth plays a role, there's a finite spray pattern they need to work in and I have a diagram of it somewhere.

Non-modified BL coils.
Just installed the stock bmw n54 triple prong spark plugs and car runs smooth and stable. Feels more powerful than the .030 NGK plugs. Will see how long they last.

So why do they say one step colder for each 100hp increase? Are these stock plugs going to go kablooey soon because of my power level increase and the BL coil voltage?

Stock plugs are easily good up 400whp or more even on stock coils (at least on pump gas), they're often swapped out way earlier than necessary IMHO. There may be quicker wear on the tips with higher current, but certainly shouldn't go kablooey. Read them once in a while to check how they're doing. If any side(s) next to a strap is getting flattened out, time to replace.

 

[RSL]

Won't really be able to see height difference in plugs, but cutaways of N54, N55 and S55. Hopefully I got the attachments in the right order.

N54:

N55:

S55:

Spray pattern. I've not been able to locate just how much of a height/angle difference #3 is, but suffice it to say, firing ends higher than stock plugs will be closer to that range. In some cases, shorter plug may actually help if the spray pattern is deformed enough to directly hit the stock length plug:

 

[SlowE93]

Won't really be able to see height difference in plugs, but cutaways of N54, N55 and S55. Hopefully I got the attachments in the right order.

N54:
View attachment 13781

N55:
View attachment 13782

S55:
View attachment 13783

Spray pattern. I've not been able to locate just how much of a height/angle difference #3 is, but suffice it to say, firing ends higher than stock plugs will be closer to that range. In some cases, shorter plug may actually help if the spray pattern is deformed enough to directly hit the stock length plug:

View attachment 13784

These are the pics I needed when I said BL coils didnt seat all the way down unless you trim and most people thought I was fullashit .

 

[fmorelli]

I was surprised about how not straight the coils go in when I first saw them.

We were very surprised. We weren't looking for it either, stumbled on it. Who would have though the plug seat in the head was not perpendicular to the shaft? That is why the R8 coil shielding needs to be cut or just removed (and probably why the shielding is built in to the shaft versus on the stock coils). On the BL coils, anyone that thinks their coils are seating properly without the proper mods is defying mathematical measurements.

Won't really be able to see height difference in plugs, but cutaways of N54, N55 and S55. Hopefully I got the attachments in the right order.

N54:

Thanks! I just added this photo to the top of the DIY Bimmerlife coil fix thread.

Filippo

 

[Rob09msport]

Out of the 3DM cars, we've now had two wiring harness failures on the BL coil setup. I'm not talking about crumbling connectors, rather harness crimps being weak and failing. Misfire on the cylinder that has the bad crimp and 2DED as the DME is pissed about electronic reality.

Trust me I want no association to this setup. PR looking better and better every day.

Filippo

Trust me i understand but honestly your diy is the first thing I'd suggest to anyone with a misfire as you found his coils prob can handle the gap most likely they just need to be modified and seated. Between your findings at one lap of America and the oxidation i saw im sure the cumulative increase in resistance can cause all kinds of issues. In hindsight i realize anyone not aware of bl coil issue might think you have some commercial involvement im editing for that reason as to not drag your name through mud by accident with my joke.