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Spark plug gap?

Old 04-08-2008, 08:51 PM
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Default Spark plug gap?

So on the advice of checking my plugs after my dyno (fail) run, i pulled them and checked the gap...... .040-.042 on all of them. I couldn't find a definitive answer to what the correct gap should be. Running 10psi. I'm thinking .028-.030 is what it should be, but i want to makw sure. So...... what should it be?
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Old 04-08-2008, 09:03 PM
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I run .025 on mine. Dosn't seem to hurt anything and keeps it firing under nitrous at 7K.
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Old 04-08-2008, 09:03 PM
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You want the biggest gap possible that does not blow out with boost. With your factory cops I'd bet you could leave them at stock .045
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Old 04-08-2008, 09:04 PM
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On stock coils you need to tighten them up, atleast with my weak '99 coils. At 9 psi i was blowing at pretty bad with .035 which is standard gap for NGK BKR7Es. So i gapped them down to .025-.026 and haven't had a misfire yet.
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Old 04-08-2008, 11:34 PM
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well, when i dyno'ed, i guess the signal was breaking up because there are whole sections of dyno plot missing. I was told this is because the spark was being blown out/bad signal. I'd feel good saying that where the dyno plot is missing is where boost was spiking due to the crappy MBC. Might i be right? The plugs im running are NGK ZFR7F-11
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Old 04-09-2008, 12:03 AM
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Old plug wires will do that. I take it he was getting signal off the little short wire, have you ever replaced those? Most miata plug wires go bad (dyno quality wise) after 30-50k miles.
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Old 04-09-2008, 08:31 AM
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it's got a set on Magacore wires that are less than 10k mi :(
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Old 04-09-2008, 08:34 AM
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bear in mind he has the 01+ cops, which JasonSBB tested as pretty freakin good at his lab.

mike, if spark were blowing out, you'd feel it as a misfire. it could be crappy wires. or it could be a crappy pick up at the dyno.
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Old 04-09-2008, 08:44 AM
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The plug gap for a 04-05 MSM with the factory COP is .028 - .031.
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Old 04-09-2008, 10:13 AM
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Originally Posted by Ben View Post
bear in mind he has the 01+ cops, which JasonSBB tested as pretty freakin good at his lab.

mike, if spark were blowing out, you'd feel it as a misfire. it could be crappy wires. or it could be a crappy pick up at the dyno.
I forget the data, but they didnt test quite as good as the 99-00 coils.
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Old 04-09-2008, 10:24 AM
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Well, on my 1st 2 runs at the dyno with the slightly higher boost, i did get several misfires and the dyno plot show'd missing segments on those runs. But on the last run, which felt clean as far as i could tell, there were still missing segments on the plot. I'm goign to tighten up the gap a bit tonight to ~.03 and see how the car feels. The 2 plugs i pulled looked fine though.

I'm also going to try to get some time in with Ed.... but they said i'd be looking at 2-3 hrs for tuning (at $150/hr... i think when they mean a "few hours", they are probably thinking a 'start from scratch' map...since i have a good base, i hope i can keep it under 2 hrs).
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Old 04-09-2008, 10:25 AM
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I know you have a boner for the Dynojet, but you need to go elsewhere to tune.
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Originally Posted by concealer404 View Post
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Old 04-09-2008, 10:26 AM
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Originally Posted by 04 Miata View Post
The plug gap for a 04-05 MSM with the factory COP is .028 - .031.
thanks for the info
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Old 04-09-2008, 10:29 AM
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Originally Posted by Ben View Post
I know you have a boner for the Dynojet, but you need to go elsewhere to tune.
i don't honestly give a flying **** as to what kind of dyno they use, monitoring a/f's is monitoring a/f's and thats all that's needed to tweak the map (and maybe keep an eye on the knock sensor). I have yet to find anyone who has first-hand experience with tuning a Hyrda other then Ed. If you know someone who has specifically tuned a Hyrda, then by all means tell me who.
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Old 04-09-2008, 10:44 AM
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horse ****.
there's a lot to do with tuning, very little of which has to do with "monitoring a/fs". there's nothing you can do on a dynojet other than take a few WOT pulls and tweak fuel somewhat. 10 minutes.

if you're going to put down money for a few hours worth of dyno tuning, you need to get on a load dyno, where you can start tuning fuel for real, and then get to your spark map. power is made in the spark map.
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Originally Posted by concealer404 View Post
Buy an MSPNP Pro, you'll feel better.
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Old 04-09-2008, 11:00 AM
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na...power is made on the power map....maybe the turbo and boost maps too.

Ummm Dynolabs and BPM use the same dyno.
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Old 04-09-2008, 11:03 AM
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Originally Posted by Doppelgänger View Post
Ummm Dynolabs and BPM use the same dyno.
and neither one is worth a damn
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Originally Posted by concealer404 View Post
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Old 04-09-2008, 11:04 AM
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wtf is a power map?
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Old 04-09-2008, 11:04 AM
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I think you can file 'power map' under 'humor'
Mike fixes computers for a living...
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Originally Posted by concealer404 View Post
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Old 04-09-2008, 11:09 AM
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hehehe...

MUST AD MORE POWERMAPS!! Powermaps are what Tom uses to show that the PCP adds intercooler effect.


Ben, i did call BPM and asked about the dyno, they did add the brake system you asked about the other day. As for load bearing.... i stand corrected. Is Dynolabs dyno a load bearing?
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