[OneMoreAlex]

Originally Posted by olivojoe

Use a little anti seize on the plug threads, makes life easier later since we have to change plugs so often due to being tuned.

From what I've read this is not recommended at all by BMW.

[Cory S]

Originally Posted by OneMoreAlex

From what I've read this is not recommended at all by BMW.

if you use use a fraction of an amount, it's beneficial, yet will not affect continuity.

[SUPAN]

Originally Posted by Unklejoe

Hello,

I'm trying to figure out which spark plugs to buy for my N55. I'd like to get one heat range colder than stock.

Many N54 people run the NGK 5992 which is one heat ranger colder than the stock N54 plug, but basically equal to the stock N55 plug. (The NGK 7 heat range is equal to the Bosch 5 heat range).

The DILKAR8A8 plug for the GTR seems like it would fit, and is an 8 heat range, which equals a Bosch 4 heat range. This ends up being one step colder than the stock N55 plug.

I found a thread somewhere else where people have reported success with this plug, but I'm looking for more feedback before I drop $20 per plug.

Jake

I am on this GTR plugs and they are solid good...
FBO with meth and stage 2 turbos.

I prefer buying this then get 5992 and then gap it to spec which workshops are relucted to do it incase damages, they do not wish to pay and errors for gapping ...

5992 or GTR plugs whichever but you have to weight the cost vs the errors /workshop whom are gapping this for you ...

[SUPAN]

Further to my last, just to share, my pal whom is on 535 n55 tried the same plugs (8a8) and got misfires ... tried the racing ones (not the stock gtr) and more misfires...

Maybe Tuning or jb4 issues.

[ocN55]

Sorry for the old bump but what's the consensus for N55 folks? If the popular 5992 NGK option is supposedly the same heat range as stock.

[olivojoe]

Originally Posted by ocN55

Sorry for the old bump but what's the consensus for N55 folks? If the popular 5992 NGK option is supposedly the same heat range as stock.

N20 plugs for the tuned N55's seem to be working the best gapped down to .018". Havent heard of any issues on here to date, and mine has been running flawlessly for about 10K miles.

[Unklejoe]

The final consensus is to use the N20 plugs. They are one heat range colder than stock.

NGK SILZKBR8D8S

[ocN55]

If someone could share the best price for the N20 plugs that'd be great. They're a lot more expensive than what I'm used to.

[Turbod]

Originally Posted by ocN55

If someone could share the best price for the N20 plugs that'd be great. They're a lot more expensive than what I'm used to.

parts.com, 12120039664.

Part Number Part Description Quantity Core Price Price Total
12120039664 SPARK PLUG 6 $0.00 $13.72 $82.32
Sub Total $82.32
Shipping method - Ground Shipping - Non Alaska/Hawaii Shipping $10.99
Handling Fee $2.00
Tax $0.00
Total $95.31

That is what I found.

[loesch]

My timing (avg ign) may have gotten worse when switching to these N20 plugs from the 5992s. Anyone else notice that? I can't think of anything else that would have changed to cause it.

[Turbod]

Originally Posted by loesch

My timing (avg ign) may have gotten worse when switching to these N20 plugs from the 5992s. Anyone else notice that? I can't think of anything else that would have changed to cause it.

Honestly I think that may be it. I just installed them and my car is not happy. I am even having some timing crashes on map 1 running 92 octane and meth 90/10.

[Cory S]

Originally Posted by loesch

My timing (avg ign) may have gotten worse when switching to these N20 plugs from the 5992s. Anyone else notice that? I can't think of anything else that would have changed to cause it.

I just switched to the NGK 95770's gapped at .021-.022". So far, they are working very well.

[loesch]

Originally Posted by Turbod

Honestly I think that may be it. I just installed them and my car is not happy. I am even having some timing crashes on map 1 running 92 octane and meth 90/10.

Hmm. How bad do you think it is to slightly tighten the gap on plugs that have some miles on them? I kind of want to set my old 5992's to .020 and reinstall them to see if there's a difference.

[Turbod]

Originally Posted by loesch

Hmm. How bad do you think it is to slightly tighten the gap on plugs that have some miles on them? I kind of want to set my old 5992's to .020 and reinstall them to see if there's a difference.

Honestly I have no Idea but I would just pay to put new ones in if I am going to tare the car down to pull the plugs again.

I had a thought as I was logging on my way to work this morning though. I assume you are running the JB4 with 5.10 ISO firmware. Since Terry added the six cylinder timing but at a lower frequency, slight timing corrections take longer to recover as the tuner sees them when in reality they recover at the same speed as cylinder one. If the correction is drastic enough to affect the AVG IGN it will adjust more drastically than before.

[loesch]

Originally Posted by Turbod

Honestly I have no Idea but I would just pay to put new ones in if I am going to tare the car down to pull the plugs again.

I had a thought as I was logging on my way to work this morning though. I assume you are running the JB4 with 5.10 ISO firmware. Since Terry added the six cylinder timing but at a lower frequency, slight timing corrections take longer to recover as the tuner sees them when in reality they recover at the same speed as cylinder one. If the correction is drastic enough to affect the AVG IGN it will adjust more drastically than before.

I'm am running 5.10. I was wondering the same thing. If I get time I'll swap them out and see if it makes a difference. It's tough trying to troubleshoot and stay married at the same time.

[kamfa39]

Originally Posted by olivojoe

N20 plugs for the tuned N55's seem to be working the best gapped down to .018". Havent heard of any issues on here to date, and mine has been running flawlessly for about 10K miles.

Totally agree

[loesch]

Yeah I think I had a bad batch of e85. My timing is back down to around 1.2 at 18psi on the pump flash and E40. The station I went to last time to stock up stopped selling e85 so I bet it was old or from the bottom of the tank.

EDIT: By timing I meant AVG IGN.

[Turbod]

Originally Posted by loesch

Yeah I think I had a bad batch of e85. My timing is back down to around 1.2 at 18psi on the pump flash and E40. The station I went to last time to stock up stopped selling e85 so I bet it was old or from the bottom of the tank.

I changed gas stations and my logs look a ton better. I think I had some bad gas too. I have 10 to 12 degrees of timing on map 2 with meth.

[bNks334]

Originally Posted by Unklejoe

Okay, I found some new info.

There are actually 5 plugs listed for the N20.

NGK SILZKBR8B8S (BMW# 12120038704)
NGK SILZKBR8C8S (BMW# 12120038896)
NGK SILZKBR8D8S (BMW# 12120039664)
NGK SILZKBR8E8S (BMW# 12120040573)
NGK SILZKBR9F8S (BMW# 12120042724)


Info:

NGK SILZKBR8B8S

This was the first N20 plug. It has been discontinued. One heat ranger colder than stock N55. Two colder than stock N54. It was replaced as per this TSB:

"As of March 2012 vehicle production, a new spark plug is being introduced in all models with the N20 engine. Its designation is NGK SILZKBR8C8S, BMW P/N 12 12 0 038 896. The new spark plug doubles the original replacement interval to 60,000 miles or every 4th engine oil service, instead of 30,000 miles/every 2nd engine oil service. The previous spark plug had the designation NGK SILZKBR8B8S. It has been discontinued."


NGK SILZKBR8C8S

Second N20 plug. One heat ranger colder than stock N55. Two colder than stock N54. This plug is what PTF recommends, but it has been discontinued. RealOEM lists the NGK SILZKBR8D8S as the replacement.


NGK SILZKBR8D8S

Current listed plug for the N20. One heat ranger colder than stock N55. Two colder than stock N54. This replaced the NGK SILZKBR8C8S listed above.


NGK SILZKBR8E8S

Current listed plug for N20's produced up to early 2015. One heat ranger colder than stock N55. Two colder than stock N54. Even though the revision is "E", it would appear that the "D" plug listed above is currently the latest recommended plug for the N20 as of today. The brand new N20 LCI motors call for the "D" plug. Maybe BMW made another revision after the "D" plug but then changed their mind and stuck with the "D" plug? IDK


NGK SILZKBR9F8S

This plug is interesting. First of all, I'm not positive that this is the correct NGK plug number. I found this info on a website that wasn't very clear. However, this plug is listed for all N20's that are "flex fuel" compatible...AKA E85. If this NGK number is correct, it would indicate that this plug is TWO steps colder than the stock N55 plug and THREE steps colder than the stock N54 plug. Maybe there's a reason for the colder plugs on motors designed to use E85?


CONCLUSION

The latest NORMAL N20 plug is the NGK SILZKBR8D8S (BMW# 12120039664). It's one step colder than the stock N55 plug and two steps colder than the stock N54 plug.

However, there's a potential new plug that was designed for flex fuel N20 motors called the NGK SILZKBR9F8S (BMW# 12120042724). This plug is two steps colder than the N55 plugs (if the NGK number is correct). I would have originally said that two steps colder is too much, but BMW seems to think that the colder plug was necessary for E85 cars, so maybe it could be advantageous to N55s as well. Someone should buy one of these so we can figure out the actual NGK number. Not it. This plug seems VERY hard to find.

Any idea why 12120039664 has several extensions such as:
12120039664-M9
12120039664-MFG9
12120039664-MFG220

Would like to order a set for my N55, but not sure if the ones I found are the right plug...

http://www.rmeuropean.com/Products/1...b-e8933a17a27f


12120039664-MFG9 are 11.79 (Genuine BMW branded) while 12120039664-MFG220 (NGK branded) are 18.46

[Titan_br]

Which one can be used in N55 engine?

When Heat range is higher is better?

http://hksusa.com/spark-plug-application-guide/