[parch8]

Hey all so wanted to start a discussion about something I've been trying to figure out about spark plug gaps on a tuned application. My 340 is running bm3 stage 2 and I know Bm3 says run .022 gap on ngks for stage 2 applications. I also see a lot of people saying run the stock .030 gap as they have no issues doing so. I am still running stock gap but bought new plugs as it's getting to that time and I'm trying to determine what I should do. I have no issues on .030 right now but I was wondering if I gap somewhere in the middle like .026 or something is that a bad idea? My main concern is people says .022 has a choppy idle so I'd prefer to keep the gap a bit more but I mainly want to do whats best for the engine and car so I wanted to see what others think ! Look forward to the discussion on this !

[Silverlining_m2]

Originally Posted by parch8

Hey all so wanted to start a discussion about something I've been trying to figure out about spark plug gaps on a tuned application. My 340 is running bm3 stage 2 and I know Bm3 says run .022 gap on ngks for stage 2 applications. I also see a lot of people saying run the stock .030 gap as they have no issues doing so. I am still running stock gap but bought new plugs as it's getting to that time and I'm trying to determine what I should do. I have no issues on .030 right now but I was wondering if I gap somewhere in the middle like .026 or something is that a bad idea? My main concern is people says .022 has a choppy idle so I'd prefer to keep the gap a bit more but I mainly want to do whats best for the engine and car so I wanted to see what others think ! Look forward to the discussion on this !

Someone will soon be through snarkily to tell you to "try the search option" and that "it's been discussed a million times".


For what it's worth, I'm on stock plugs with good timing. It's about time to change them and I plan to keep them that way unless it becomes necessary to swap.

[parch8]

Originally Posted by f32spaceship

Someone will soon be through snarkily to tell you to "try the search option" and that "it's been discussed a million times".


For what it's worth, I'm on stock plugs with good timing. It's about time to change them and I plan to keep them that way unless it becomes necessary to swap.

No I know people have mentioned gaps before I just wanted to see what people thought about gaping somewhere in the middle instead of one or the other and thoughts in general before I threw mine in. But I appreciate your opinion and not being snarky about sometimes the forums get a bit testy like that lol.

[trescuarenta]

Im at 600+ whp still stock plugs stock gap.

[dmanb2b]

Stock gap. You found a recommendation on BM3 website to change the gap on stage 2, specific to the B58? I think you may be reading old documentation on n55.

[chenry]

For what it's worth - not BM3 but close enought...my experience:

I drove my Mission Performance 340 stage 2 for quite some time (1000's of miles) with the stock gap. While MP does not say it is 100% necessary to gap the plugs to .022 Alex does recommend it.

Car was just fine on the stock gap but just became a bit smoother (Noticeably so) once I gapped my stock plugs.

Frankly, I was surprised...I didn't think I would notice a difference. Certainly nothing dramatic but if you are tuned (no pun intended) to how your car drives you will indeed notice a difference.

I think it is worth it and would do it again (in fact I did do it again now with my M340 Stage 2) Hope this helps...

[parch8]

Originally Posted by chenry

For what it's worth - not BM3 but close enought...my experience:

I drove my Mission Performance 340 stage 2 for quite some time (1000's of miles) with the stock gap. While MP does not say it is 100% necessary to gap the plugs to .022 Alex does recommend it.

Car was just fine on the stock gap but just became a bit smoother (Noticeably so) once I gapped my stock plugs.

Frankly, I was surprised...I didn't think I would notice a difference. Certainly nothing dramatic but if you are tuned (no pun intended) to how your car drives you will indeed notice a difference.

I think it is worth it and would do it again (in fact I did do it again now with my M340 Stage 2) Hope this helps...

What did you notice for differences? Like the smoothness of acceleration? Also congrats on the m340i I absolutely love them and am super jealous !!

[chenry]

Originally Posted by parch8

What did you notice for differences? Like the smoothness of acceleration? Also congrats on the m340i I absolutely love them and am super jealous !!

Oh thank you yes enjoying the M340 but miss my 340 (yes yes first world problems) it is nice though to make 470ish wheel with simply a stage 2 tune and DP

To your question - yes smoother is a good way to describe it - and mind you I was perfectly happy (make that very happy) with my MP stage 2 prior to gapping the plugs - but at the same time I didn't know what I was missing. Didn't think I would notice a difference by simply changing the gap - but I did and I'm sure you will too

It made something that was already great just a bit better

Hope this helps...

[kern417]

Leave the gap alone.

[parch8]

Originally Posted by chenry

Oh thank you yes enjoying the M340 but miss my 340 (yes yes first world problems) it is nice though to make 470ish wheel with simply a stage 2 tune and DP

To your question - yes smoother is a good way to describe it - and mind you I was perfectly happy (make that very happy) with my MP stage 2 prior to gapping the plugs - but at the same time I didn't know what I was missing. Didn't think I would notice a difference by simply changing the gap - but I did and I'm sure you will too

It made something that was already great just a bit better

Hope this helps...

Appreciate the info and completely I am curious to see it might be worth doing stock gap then trying smaller gap and see if I notice a difference since it's not too much extra effort But yes totally jealous would love to have gone the m340 for the interior alone but I went from a Nissan Altima to my stage 2 340 so I guess that's enough change for one year that I can't complain 😂😂.

[dmanb2b]

Originally Posted by kern417

Leave the gap alone.

^^^ this. Unless someone has logs showing less timing corrections on a smaller than stock gap, I'm not changing it. I have yet to see any logs indicating that changing the gap would benefit those on an OTS tune. There is a bunch of chatter showing Champions may actually perform better than NGK, but that's a whole 'nother oil debate.

[Supr3me]

Originally Posted by chenry

Oh thank you yes enjoying the M340 but miss my 340 (yes yes first world problems) it is nice though to make 470ish wheel with simply a stage 2 tune and DP

To your question - yes smoother is a good way to describe it - and mind you I was perfectly happy (make that very happy) with my MP stage 2 prior to gapping the plugs - but at the same time I didn't know what I was missing. Didn't think I would notice a difference by simply changing the gap - but I did and I'm sure you will too

It made something that was already great just a bit better

Hope this helps...

Can you tell me more about why you miss your 340i? I'm contemplating making the switch to an M340i

[chenry]

Originally Posted by Supr3me

Can you tell me more about why you miss your 340i? I'm contemplating making the switch to an M340i

Sure

While I miss the 340 I am very much enjoying the M340 - and all things considered would not go back. That said I find the F30 platform to be more visceral, engaging, and intimate which I like. Fortunately I still have the opportunity to jump back in an F30 and I enjoy the time behind the wheel when I do (mind you I still enjoy an e36 for that matter)

All things considered the M340 is very capable and impressive car, and it is deceptively fast/quick. The B58TU takes the already wonderful B58 and makes it just that much better. And if you're one to mod.....with a simple stage 2 tune, E30 and a DP you're comfortably making 470 wheel all day long which is nice

I think most anyone that has enjoyed a 340 will be happy getting behind the wheel of an M340....but that doesn't mean it's better...it's just different. A nice evolution of the species.

Hope this helps....