Tried the m5 plugs @ 25 psi on a number of rides without any issues so far. Did not change the gap.
N55: What Spark Plugs do you use?
- Thread starter doublespaces
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Yeah - I was referring to the N54.
Usually it’s the Delphi for the N55.
It would be interesting to try the Eldors on the N55 though....
I just went to 97506's on mine, gapped at .020. Runs fine in daily driving, will be turning it up higher this week and running NFZ AZ next weekend with them.
I think I am meeting up with some others on the west side of town. I'd like to arrange a meet spot on the East side, then we can join them on the way out there. I am coming form Gilbert.
N55 stock turbo DCT w/ catless DP, magnaflow full exhaust, chargepipe, VRSF 7.5” race IC, custom E50 tune.
Over the last week I’ve tried;
95770 (oem heat range) @ .024, .022, and .018
96987 N20 ‘E’ rev (1 step colder) @ .024, .022, and .018.
95770 was best at .018 but best overall have been N20 at .022. With 95770 I would get some logs with zero corrections and some logs with huge corrections. N20 at .024 I had small random corrections on most logs. N20 @ .022 feels the best and has zero corrections or very small short corrections. Drivability/cold start/idle was poor on the N20s at .018.
https://datazap.me/u/sbrach/rev59?log=2&data=3-12-15-25-26-27-28-29-30
Over the last week I’ve tried;
95770 (oem heat range) @ .024, .022, and .018
96987 N20 ‘E’ rev (1 step colder) @ .024, .022, and .018.
95770 was best at .018 but best overall have been N20 at .022. With 95770 I would get some logs with zero corrections and some logs with huge corrections. N20 at .024 I had small random corrections on most logs. N20 @ .022 feels the best and has zero corrections or very small short corrections. Drivability/cold start/idle was poor on the N20s at .018.
https://datazap.me/u/sbrach/rev59?log=2&data=3-12-15-25-26-27-28-29-30
Thanks for posting and doing the testing. Did you ever try stock gap, stock plug? That is what I ran on stock turbo without any issues.
I currently run the N20 plugs, rev e I believe, gapped at .021. Car runs great up to 19psi on PS2. But above 20psi I randomly get misfires even though my log looks perfect. I assumed it was the stock DCT flywheel. I emailed Justin from twisted tuning to see if he had any ideas why I randomly get misfires above 19psi. One thing he recommended I check was my spark plug gap as well as running the stock heat range plug vice the N20. He said that up to 700ish WHP the N20 plugs are not needed. Stock plug or NGK 95770 are best and anything smaller than a .022 gap is too small, and even .022 is small.
So at some point I will throw some stock plugs in at a gap bigger than .022 and see how things go.
Cold start is better with 95770s for sure. Idk, my logs are a lot cleaner on N20s at .022 then any gap on the 95770s. Single low gear logs would usually be clean (zero corrections) but multi gear or high gear high boost/load logs would have huge corrections across multiple cylinders and would not correct back up.
N20s have more random -3 corrections but less major corrections and less multi cyl corrections. Also feels much smoother if I lug it at low rpm / high gear.
N20s have more random -3 corrections but less major corrections and less multi cyl corrections. Also feels much smoother if I lug it at low rpm / high gear.
NGK has discontinued the NGK 96987 SILZKBR8E8S spark plugs and they have been replaced by the SILZKBR8D8S (97506). That is probably why you can find the newer "revision E" plug so cheap at around 1/2 the price of the older "revision D" plug. It's been stated in many threads to use the SILZKBR8D8S plugs if you want one step colder. People have reported poor results with the 96987 plugs. If you want two steps colder, you want the NGK SILZKBR9F8S - (BMW# 12120042724).
https://www.ngk.com/product.aspx?zpid=40569
What is the difference between N20 plugs labeled SILZKBR8E8S (96987) and SILZKBR8D8S (97506)? According to NGK, the codes tell us that the discontinued 96987 plug has a different firing end construction that doesn't appear to have worked too well.
http://www.sparkplugs.com/Data/uploads/Charts/NGK_Plug_Chart_2.jpg
I run the N20 1-step colder plugs with NGK part number: SILZBR8D8S (97506). I gaped them to .026." I've replaced them 2x already and both times they came out looking to be operating perfectly on a hard driven car. I chose .026" because it's somewhat of a middle ground between gaping down by .010" to improve performance and leaving the gap stock for idle and economy. I might try going 2-steps colder because the plugs look to run a bit on the hot side still.
I also run the N55 eldor coils. They are supposed to be an improvement in design over the stock Bosch coils which started to misfire at around 100k miles. The Eldor coils have a metal band around them for cooling? Seems to work great and they are cheaper.
I have never had any problem running plugs at .026" with as much as 24psi at low rpm on the stock turbo. I now have a hybrid (PS1 equivalent) in the car and still don't have any issues. I am not too sure why N55, and even most N54, owners think they need to gap plugs down. Probably has something to do with early days of N54 tunign and JB4 only tuning where owners (and their tuners) thought it was OK to run 1300psi rail pressure. Then blamed park plug gap for the resulting misfires LOL
BMW forums is the only place I can really find anyone relating timing corrections to spark plugs... Timing corrections are the result of knock. Bad spark plugs usually result in misfires. Changing spark plug gap has such a minute affect on ignition advance that it doesn't make any sense for it to have a meaningful impact on timing corrections and knock.
People gap plugs down to prevent spark blowout (misfires) in high compression applications. They don't do it to fix timing corrections (knock). And, people run colder temp spark plugs when making more power to keep the spark plugs from melting or glowing causing pre-ignition. Due to the higher in cylinder temperatures and quicker acceleration the spark plug has less time to shed heat and needs to be 1 or 2 steps colder (which is a rating of how quickly the spark tip sheds heat).
The only caveat to the above is that a colder plug that idles a lot may foul out if you don't run your car hard. Again, this wouldn't be the spark gap causing timing corrections (knock) but rather a too-cold spark plug causing carbon buildup.
https://www.ngk.com/product.aspx?zpid=40569
What is the difference between N20 plugs labeled SILZKBR8E8S (96987) and SILZKBR8D8S (97506)? According to NGK, the codes tell us that the discontinued 96987 plug has a different firing end construction that doesn't appear to have worked too well.
http://www.sparkplugs.com/Data/uploads/Charts/NGK_Plug_Chart_2.jpg
I run the N20 1-step colder plugs with NGK part number: SILZBR8D8S (97506). I gaped them to .026." I've replaced them 2x already and both times they came out looking to be operating perfectly on a hard driven car. I chose .026" because it's somewhat of a middle ground between gaping down by .010" to improve performance and leaving the gap stock for idle and economy. I might try going 2-steps colder because the plugs look to run a bit on the hot side still.
I also run the N55 eldor coils. They are supposed to be an improvement in design over the stock Bosch coils which started to misfire at around 100k miles. The Eldor coils have a metal band around them for cooling? Seems to work great and they are cheaper.
I have never had any problem running plugs at .026" with as much as 24psi at low rpm on the stock turbo. I now have a hybrid (PS1 equivalent) in the car and still don't have any issues. I am not too sure why N55, and even most N54, owners think they need to gap plugs down. Probably has something to do with early days of N54 tunign and JB4 only tuning where owners (and their tuners) thought it was OK to run 1300psi rail pressure. Then blamed park plug gap for the resulting misfires LOL
BMW forums is the only place I can really find anyone relating timing corrections to spark plugs... Timing corrections are the result of knock. Bad spark plugs usually result in misfires. Changing spark plug gap has such a minute affect on ignition advance that it doesn't make any sense for it to have a meaningful impact on timing corrections and knock.
People gap plugs down to prevent spark blowout (misfires) in high compression applications. They don't do it to fix timing corrections (knock). And, people run colder temp spark plugs when making more power to keep the spark plugs from melting or glowing causing pre-ignition. Due to the higher in cylinder temperatures and quicker acceleration the spark plug has less time to shed heat and needs to be 1 or 2 steps colder (which is a rating of how quickly the spark tip sheds heat).
The only caveat to the above is that a colder plug that idles a lot may foul out if you don't run your car hard. Again, this wouldn't be the spark gap causing timing corrections (knock) but rather a too-cold spark plug causing carbon buildup.
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The Bosch ZMR5TPP330 (12120039634) plugs from the S55 appear to be same heat range as a stock N55 BOSCH ZR5TPP33S plug (12120037582) (Bosch 5 = NGK 7). In fact, the plugs are identical according to their codes. The only exception is that the S55 plug ends in "0" instead of "S" which simply means it's the same plug but with "differences from basic design." What's the differences? I am not sure but it's probably just a marketing type thing so they can mark up the S55 plugs. Sounds like S55 plugs = N55 plugs. All 3 plugs (N20/N55/S55) produced by Bosch are double platinum. The NGK plugs noted in my previous post are iridium. You can google that difference yourself. NGK plugs seem to be the way to go though as people have had problems with the S55 Bosch plugs breaking.
Basically, don't bother with S55 plugs it's the same damn thing as stock N55 plugs. Go with NGK plugs and 1-step colder, imo.
https://www.briskusa.com/spark_plug_cross_reference_heat_range_chart
https://www.euromotoelectrics.com/v/vspfiles/assets/images/superplus_designationcodes_10.pdf
Tony's post support the idea that stock plugs at stock gap are going to be just fine. Not sure what engine or turbo he is referencing though when he says he runs "25psi." Facebook shows that they have a N54 335i with stage 2 turbos... S55 plugs for this application would be 1-step colder but still stock gap...
Basically, don't bother with S55 plugs it's the same damn thing as stock N55 plugs. Go with NGK plugs and 1-step colder, imo.
https://www.briskusa.com/spark_plug_cross_reference_heat_range_chart
https://www.euromotoelectrics.com/v/vspfiles/assets/images/superplus_designationcodes_10.pdf
Tony's post support the idea that stock plugs at stock gap are going to be just fine. Not sure what engine or turbo he is referencing though when he says he runs "25psi." Facebook shows that they have a N54 335i with stage 2 turbos... S55 plugs for this application would be 1-step colder but still stock gap...
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Thanks for the thorough breakdown brother. My car has been running good with 96987's gapped at .021, but I am going to switch to the 97506 based on the information you provided. With the constant improvements by @Sbrach on tuning the N55, especially on the fueling side of things, I am curious how my car will run with a larger gap like .03 or .026.
This is what happens when your boss doesn't give you any work to do... you google random stuff and argue with people on the internet all day LOL
@houtan I updated my post above. the difference isn't reach. The difference in teh plug is the firing end construction. I copied bad information from another post. Either way, people have reported poor results with the "E" plugs and even NGK discontinued them for the "D" plug.
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