Quote:
Originally Posted by F15_SGM
No need to cheap out on plugs, Platinum vs Iridium. The part number is not even the same. Most of everyone that still claims bosch is good have the zr5tpp33-S variant, and they think it's the zr5tpp33. As examples in the link in my prior post, people were posting zr5tpp33-s and saying they have zr5tpp33. The zr5tpp33 are nothing but trouble after some time. You can only purchase the zr5tpp33-s with BMW stamped Bosch. Also, the OP also has zr5tpp33. Same symptoms as mine with weak coils. NGK is a far superior brand than bosch in the plug world, and The OEM plug for a 4-cylinder N20 is also the same NGK 97506. From my experience using the NGKs, the engine is smoother than ever before, even comparing them to my OEM Plugs zr5tpp33-s. Although if your car calls for it, then why not. You don't need to gap them for a stock application. The quality control on bosch products is no good nowadays. I read everything prior to getting that zr5tpp33 and wish I never listened to anybody that supports bosch plugs or anyone saying they are the same as Oem. I only replaced them as preventive as my OEM BMW zr5tpp33-s were still great with 90K on them. When I swapped the zr5tpp33 for another one, they exhibit the same behavior as OP after a short amount of time as well. After further research, its something to do with Quality control and the tighter electrode gap and larger internal resistor that dissipates heat faster/ground differences between zr5tpp33 and zr5tpp33-s. As I said, some cars just call for it. Also, mine are gapped to 0.020, and I'm only stage 1 bm3 nothing serious, and have no issues at all. If you absolutely don't want ngk not sure why not though, but you can get the BMW OEM plugs that are bosch zr5tpp33-s.
https://www.bimmerfest.com/threads/c.../post-13410647
Thread #19. |
Not here to argue, just saying that that this exact thing - the bosch with the S vs. without the S vs. the NGKs and related discussions on gap has happened countless times over the last several years. The bosch without the S are just fine. I am running them, have been for years, on MHD stage 2+ 91 octane and E20 using E30 fuel. OP can read N55 tech forums if he wants or just pick. Nothing is necessarily WRONG with the NGKs, but the issue is running a colder plug with a smaller gap if you dont need it. Short trips and lower power level with gold plugs and small gap and caused fouled plugs. And in general, you want the largest gap you can for good combustion