[Supahone]

In doing a search on the forum. It appears there has been a wide range of gap specs for a 2011 550i especially if they have been tuned. My question is on a stock F10 2011 550i what is the best gap setting for spark plugs. I currently have mine gapped at 28. though I've seen them as high as 35. Stated pros and cons would greatly be appreciated.

[535_BiTurbo]

Mine are at .28 as well

[550iFreak]

2011 550i, 6mt.
Catless downpipes
Jb4
Muffler delete
90 degree celcius thermostat

I tried three different spark plugs, all at different gap specs. Here's my input.

Stock bosch plugs, not gap serviceable. Must retain its gap from the factory which I believe is .030 or so. Works well in stock. Stage 1 is pushing it, will cause occasional drivetrain malfunction. Stg 2 is useless due to high boost.

Pros: stock drivability, very smooth. Retains best fuel economy


Then I have the NGK one step colder plugs that came factory on minis ( 97506) iirc.

Currently installed at gap 0.029-0.030

The car LOVES it. Drivability improved under stock. Stock feels like stage 1. Stage one is usable to full send. Stg 2 causes occasional drivetrain malfunction after 130 mph but I rarely use stg 2. Stage one is quick enough for me and stockform is like stage 1 but with awesome drivability.

Same plugs on 0.020- 0.018 gap
Able to use stage 2, monster amount of power.

Unfortunately here's the cons on that setup
Cold start compromise, rough acceleration at cold. Once warmed up, it is slightly jerky. Drivability decreased. Fuel economy also diminished.

Pros: Able to use full potential of jb4

Last plug was 2 step colder ngk that was used on newest me and m4s

Gap either on 0.029 or 0.018 NOT A GOOD PLUG ON MILD SETUP. NOT GOOD FOR DRIVABILITY.

I realized that it is only used for heavily modded cars with big turbos, etc.


So........if yours is completely stock, use stock plugs at stock gap. Leave it alone.

Slight mods like mines really likes the one step colder ngk at similar gap specs.

Hope this helps

Also, the jb4 I have is the newest version where I have selectable maps. Map 0, 1, and 2 are used. 0 and 1 are used the most while map 2 is used rarely to "prove a point" which again is very rare. Cant use map 7 since my fuel wires are not connected and I love my car and engine. Cant blow her up lol.

If it means anything, my current setup at map 1 was used at my first drag race at the strip and smoked a fbo c5 corvette. Nothing fancy, even asked the guy if his was having issues. He said no, you are just abit quicker lol. Only by 1 or so Car lengths but I'll take it for my boat lol.

[Supahone]

Much appreciated. So clearly .28 is too low for a stock 550i?
Funny enough I experienced a brief misfire holding 4th gear through 6k rpms. It made me think to swap out plugs as the car was new to me with 92k miles. When I removed what seemed to be the original old chalky spark plugs the gaps ran with six that were measured at .32 and two that were .35, .40

[Cali8055]

So what gap is recommend with ngk cold start for a n63tu engine ? I have a 14 550i

[TuckerE36]

Originally Posted by Supahone

Much appreciated. So clearly .28 is too low for a stock 550i?
Funny enough I experienced a brief misfire holding 4th gear through 6k rpms. It made me think to swap out plugs as the car was new to me with 92k miles. When I removed what seemed to be the original old chalky spark plugs the gaps ran with six that were measured at .32 and two that were .35, .40

Stock gap is 0.032"

Originally Posted by Cali8055

So what gap is recommend with ngk cold start for a n63tu engine ? I have a 14 550i

This one is tough because the NGK 97506 plug is for tuned motors. You can run a NGK plug at stock gap and see how it drives

[Cali8055]

Got you damn I searched for plugs and went with this one just to now finding out it’s for tuned lol I might try em out at stock gap see how it goes on the 63tu .

[ctcarbonari]

Originally Posted by Supahone

Much appreciated. So clearly .28 is too low for a stock 550i?

FWIW,

My 15' 535i (N55)
OE Plugs are BMW rebranded Bosch ZR5TPP33S Factory gapped @ .028"
OEM Plugs are Bosch ZR5TPP33 Factory gapped @ .031"
(-S designated plugs have a higher resistance rating)

https://www.boschsparkplugs.net/

I think the gap spec on a stock N55 is .030" (+/- .002")

I know it's comparing apples vs oranges a bit (N55 vs N63) but I thought the simularities in spark plug specs & differences were worth sharing.

[TuckerE36]

Originally Posted by Cali8055

Got you damn I searched for plugs and went with this one just to now finding out it’s for tuned lol I might try em out at stock gap see how it goes on the 63tu .

Yeah see what happens, worse case it idols rough lol