[JLGM4]

I've seen a few variations but want to make sure I'm getting the right ones for my n55. I gap them to .018 correct?

Mods are pure stage 2, fuel it stage 2, FBO

[DrRobert]

Here you go. .018 is working well for me, AFAIK that is the recommended gap for PS2 N55s.

http://www.realoem.com/bmw/enUS/part...&q=12120039664

https://www.ecstuning.com/b-genuine-...s/12120039664/

[JLGM4]

Originally Posted by DrRobert

Here you go. .018 is working well for me, AFAIK that is the recommended gap for PS2 N55s.

http://www.realoem.com/bmw/enUS/part...&q=12120039664

https://www.ecstuning.com/b-genuine-...s/12120039664/

Thank you!

[bbnks2]

Originally Posted by jgottsman11

Thank you!

Those plugs are only 1 step colder for N55's.

Two steps colder for N55 would be the NGK SILZKBR9F8S (BMW# 12120042724) plugs...

For 1 step colder you want NGK SILZKBR8D8S (BMW# 12120039664).

[DrRobert]

Originally Posted by bbnks2

Those plugs are only 1 step colder for N55's.

Two steps colder for N55 would be the NGK SILZKBR9F8S (BMW# 12120042724) plugs...

For 1 step colder you want NGK SILZKBR8D8S (BMW# 12120039664).

Oops, sorry about that OP! And thanks for the correction bbnks2. But I thought 1 stage colder was what we are advised to use for PS2 N55s. That is what I am using on mine with good results.

[JLGM4]

Well anyways I went with what Dr Robert said. Either way I'm at 21 psi now with no problems so im not too worried about it.

[DrRobert]

Again, sorry if I gave you info that was not what you were after. But now you have me curious. When I got my PS2 Dzenno at PTF told me to get one step colder plugs gapped to .018 , and gave me the link I gave you. I'm on my second set now and they have worked well for me since day one. Ken at Wedge is my tuner now, and he said to keep the same plugs, same gap. When and why would one want to go two steps colder?

[bbnks2]

The general rule is go 1 step colder for each additional 100hp.

However, the stock plugs seem to work fine for most people even at higher power levels. 1 step colder being a bit safer to prevent predetonation at 500whp+ levels.

[DrRobert]

Originally Posted by bbnks2

The general rule is go 1 step colder for each additional 100hp.

However, the stock plugs seem to work fine for most people even at higher power levels. 1 step colder being a bit safer to prevent predetonation at 500whp+ levels.

Thanks for explaining that. 1 step colder is the right plug for me then, hope it is for you too OP!

[GripAndRip]

Originally Posted by bbnks2

The general rule is go 1 step colder for each additional 100hp.

However, the stock plugs seem to work fine for most people even at higher power levels. 1 step colder being a bit safer to prevent predetonation at 500whp+ levels.

Is there any downside going two step colder when you aren't making 200+ hp over stock? I ended up buying 2 step colder in case I ever take the car that far. There was like a three dollar difference per plug so I said screw it why not.

Haven't installed them yet.

[bbnks2]

Originally Posted by GripAndRip

Is there any downside going two step colder when you aren't making 200+ hp over stock? I ended up buying 2 step colder in case I ever take the car that far. There was like a three dollar difference per plug so I said screw it why not.

Haven't installed them yet.

I'm not an expert, but the main issues stem from tuning for high whp on a daily driver.

Tuning for optimal plug performance becomes harder as the delta between daily driving and wot performance increases. Daily driving could foul up your plugs if they are running too cold.

Choosing the right temp plug is best done through observation. Run 1 step colder and see what color the plugs are after 5k miles... are they burnt (white=too hot) or are they fouled (black soot = too cold). Everyone's driving style is different.

https://www.ngksparkplugs.com/about-...rk-plug-basics

[GripAndRip]

Originally Posted by bbnks2

I'm not an expert, but the main issues stem from tuning for high whp on a daily driver.

Tuning for optimal plug performance becomes harder as the delta between daily driving and wot performance increases. Daily driving could foul up your plugs if they are running too cold.

Choosing the right temp plug is best done through observation. Run 1 step colder and see what color the plugs are after 5k miles... are they burnt (white=too hot) or are they fouled (black soot = too cold). Everyone's driving style is different.

https://www.ngksparkplugs.com/about-...rk-plug-basics

If I plan on doing a tune similar to Bahn's e30 custom tune, do you think it's wise to rock 2 step colder?

[JETmn]

Originally Posted by bbnks2

Daily driving could foul up your plugs if they are running too cold.

Yes, this is the downside to too cold of plugs. Very few people on here would benefit from 2 ranges colder plugs.

[bbnks2]

Originally Posted by GripAndRip

If I plan on doing a tune similar to Bahn's e30 custom tune, do you think it's wise to rock 2 step colder?

I don't think so. People use stock plugs at that power level without issue to be honest.

[GripAndRip]

Originally Posted by bbnks2

I don't think so. People use stock plugs at that power level without issue to be honest.

Nice. I couldn't remember if I bought 1 step or 2 step colder and got a little worried. I rechecked the ngk part number and I bought 1 step colder so I'm not worried.

[houtan]

Originally Posted by GripAndRip

If I plan on doing a tune similar to Bahn's e30 custom tune, do you think it's wise to rock 2 step colder?

I think he is running the stock plugs, but not sure. I have always run stock plugs, stock gap, and my logs are clean. Feel free to check them out as another reference point for wedge tune on ethanol.

http://www.1addicts.com/forums/showthread.php?t=1146223

[GripAndRip]

Originally Posted by houtan

I think he is running the stock plugs, but not sure. I have always run stock plugs, stock gap, and my logs are clean. Feel free to check them out as another reference point for wedge tune on ethanol.

http://www.1addicts.com/forums/showthread.php?t=1146223

I'm assuming I'm on stock plugs with stock gap currently. However I bought the car at 50k miles and don't know if previous owner changed the plugs or not. I'm at 67k now. I bought 1step colder. I think I'll keep them on the side and if I have issues I'll change the plugs.