Plug Gap for BKR7E-11 @ 13-15psi? - Miata Turbo Forum - Boost cars, acquire cats.

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Old 04-28-2008, 02:38 PM   #1
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Default Plug Gap for BKR7E-11 @ 13-15psi?

I currently have them gapped at .039 on my 1.6 with MSPNP. I am experiencing the misfire issue as discussed in other threads. Is the gap too high? Are there going to be any adverse effects from lowering the gap down? Nobody really elaborated on the plug gaps other than that you want to run as big of a gap as you can without blowing out boost. I am also looking into adding additional grounds to the ecu, but in the meantime was wondering if I should change the gap on my plugs.

Thanks in advance for your answers.


Quinn


More detail on my setup can be seen here:

http://www.clubroadster.net/forum/vi...er=asc&start=0
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Old 04-28-2008, 02:41 PM   #2
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I run .020 and it works fine. Some will speculate you get an extra 2 hp with running a larger gap, but if you have the slightest misfire at high RPMs, you loose a lot more than 2 HP. IMO run .020 or .025. I run .020 for my nitrous and no misfires here.
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Old 04-28-2008, 02:45 PM   #3
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upgrade to C.O.P.s
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Old 04-28-2008, 02:51 PM   #4
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upgrade to C.O.P.s
lol, how did I know you were going to say that. I would like to try these first before starting another project. What are your gap recommendations Braineack?
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Old 04-28-2008, 02:54 PM   #5
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I don't think you're going to be able to run larger than .030 gap, probably more like .025

I'm going to open the gap on mine up to .050 and see what happens. No issues to almost 18 psi at .045
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Old 04-28-2008, 02:55 PM   #6
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Quote:
Originally Posted by JDM Quinn View Post
lol, how did I know you were going to say that. I would like to try these first before starting another project. What are your gap recommendations Braineack?
I personally was running .030 on my 15psi (t3 60/63) 1.6L honda setup... but miata people seem to need smaller gap (weaker ignition system?) on the similar sized motors.

I'd run as suggested by those that have it working for them. .020 sounds super small to me (ie: easy to foul the plugs), but if its working... can't argue with that.
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Old 04-28-2008, 03:03 PM   #7
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I ran .030 at 12psi never had an issue. never had to play with it.
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Old 04-28-2008, 03:07 PM   #8
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Yea it does kinda foul plugs, but then again I'm running two heat range cooler plugs when 99% of the time I'm not spraying nitrous. If I were turbo and hit boost everyday, they would probably stay cleaner. But it does run fine so no complaints yet. Besides, I'm not trying to get 50K miles out of my plugs, they get changed every couple months anyway.

FWIW, it had a BAD misifire at .035 on the bottle. I gapped to .025 and that helped a ton, probably fixed it. I just run .020 anyway so I don't have to worry about a misfire, as it can cause a lot of damage on a nitrous motor and rob lots of HP.
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Old 04-28-2008, 03:13 PM   #9
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Quote:
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I don't think you're going to be able to run larger than .030 gap, probably more like .025

I'm going to open the gap on mine up to .050 and see what happens. No issues to almost 18 psi at .045

You also mentioned in another thread that you added additional grounding to the MSPNP. What exactly did you do?
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Old 04-28-2008, 03:43 PM   #10
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Uhm. Ran additional grounding. That's cryptic?

LOL, sorry for being facetious. One of the guys at DIY soldered in a jumper lead from the main ground pad and broke it out to extra pins in the center connector. Ran 3 leads from the center connector the the head. Also cleaned up the 2 factory grounding points at the head.

Car runs like a freakin champ.
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Old 04-28-2008, 04:11 PM   #11
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Uhm. Ran additional grounding. That's cryptic?

LOL, sorry for being facetious. One of the guys at DIY soldered in a jumper lead from the main ground pad and broke it out to extra pins in the center connector. Ran 3 leads from the center connector the the head. Also cleaned up the 2 factory grounding points at the head.

Car runs like a freakin champ.

Thats why I was wondering, because I asked Atlanta93LE and he said that:

"I opened the ECU and added a jumper from the ground pin to an open pin on my extension harness, and ran that from the harness to the engine grounding point. I run a MSPNP 9093; the later cars had more grounds from the factory."

So I am wondering if someone has posted instructions how to do this, because I am not one to play around with PCB's and soldering.
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Old 04-28-2008, 04:14 PM   #12
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Quote:
Originally Posted by JDM Quinn View Post
because I am not one to play around with PCB's and soldering.
then don't. plain and simple. DIYautotune will help out if you send them your mspnp. They have very reasonable shop rates, and you can be assured it is done right the first time.
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Old 04-28-2008, 04:30 PM   #13
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then don't. plain and simple. DIYautotune will help out if you send them your mspnp. They have very reasonable shop rates, and you can be assured it is done right the first time.

Let me rephrase that. I wouldnt feel comfortable going in a soldering things unless I had a good picture diagram showing specifically what needs to be done. I am not one to "f" with stuff that I am not sure about. If no one has them, I will send mine in to DIYautotune.
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Old 04-28-2008, 04:32 PM   #14
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Dude, open it up, look for GND, solder to that, be happy

or send it to DIY
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Old 04-28-2008, 06:02 PM   #15
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i was using those plugs and had the same problem.
Switching to 3033 plugs with .031 gap fixed my misfire.
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