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-   -   What spark plug gap? (https://www.miataturbo.net/engine-performance-56/what-spark-plug-gap-40931/)

triple88a 11-06-2009 07:05 PM

What spark plug gap?
 
I've been searching around and got a lot of answers to the same question :facepalm:

I just bought a set of NGK Power coppers. What should they gap?

So far i've seen people saying .045", .040", .039", .035", .030" and .020". Which one is it? I'm running stock ignition system so i assume the 45 is too much since thats more for COPs.

Braineack 11-06-2009 07:06 PM

.035-.030"

triple88a 11-06-2009 07:11 PM

Thank you sir :)

hustler 11-06-2009 07:12 PM

.025 was the most I could run on the stock coil. I run .050 with the Toyota cops. The seemed to blow-out in colder temps, so you may want to take .005 out if its warm out (but you're in Chi-Town so its probably cold).

gospeed81 11-06-2009 08:31 PM


Originally Posted by hustler (Post 479097)
.025 was the most I could run on the stock coil. I run .050 with the Toyota cops. The seemed to blow-out in colder temps, so you may want to take .005 out if its warm out (but you're in Chi-Town so its probably cold).

This exactly...but my stock coil gaps were closer to 0.020...so I was in a real rush to get COPS.

I run the 0.041 gap with them as they come out of the box.

kotomile 11-06-2009 08:53 PM

I gapped around .025 @ 14 psi before I got CoP.

triple88a 11-06-2009 09:06 PM

so wait, its better to go less with the turbo otherwise it blows out?

18psi 11-06-2009 09:10 PM

I had my BKR7E's gapped to .030 and they worked great.
You want a smaller gap when turbo'd, yes.

Braineack 11-06-2009 09:13 PM

unless you have a real ignition system where you can get away with .043" like me on my cheap ass Autolite 3922s

18psi 11-06-2009 09:19 PM

Definitely planning to go COP in the future;)

Rushin 11-06-2009 09:25 PM

Does anyone at the moment makes COPs to order on here?

18psi 11-06-2009 09:27 PM

You have a 90. Brain made a big ass thread about doing it for the earlier years. Just follow that and I don't think youll have problems.

Us NB people don't have a step by step like that. Even though its similar its not the same AFAIK.

oh well

Rushin 11-06-2009 09:31 PM

i would just like to get a premade one if anyone makes it. I did see the big thread with a step by step how to .

gospeed81 11-07-2009 07:34 AM


Originally Posted by triple88a (Post 479142)
so wait, its better to go less with the turbo otherwise it blows out?

It's not better, it's a necessary compromise.

Larger gap is "better"...but it can blow out with stock ignition system at boost above about 10psi (for me). I think my coils were getting pretty damn tired at 240K miles...and COPS were like espresso for my motor.

triple88a 11-07-2009 04:38 PM

2 Attachment(s)
What do you guys think? The lower right is number 3... 2nd to the back of the engine

it had some oil on the rim (the washer/gasket) but i dont know if its from when i did the compression test or whatever.

There was no oil on the tip or the threads of the spark plug.

Attachment 202657

Attachment 202658

Turbo_4 11-07-2009 08:56 PM

Looks just a little lean.

evank 11-07-2009 09:38 PM

I'm currently running .020. I tried .025 and got blow-out above 12 psi. Now I'm waiting for my Boundary/WeaponX COPS to arrive .... dreaming of big-gap goodness!!!

gospeed81 11-07-2009 09:57 PM


Originally Posted by Rushin (Post 479152)
i would just like to get a premade one if anyone makes it. I did see the big thread with a step by step how to .

Just do it man.

I wanted to order some too...and then found all my COPS on eBay for $80 shipped and just started doing it one day...took an afternoon.

The big how to is much shorter when you clip out the parts you don't need.

Braineack 11-08-2009 11:01 AM


Originally Posted by evank (Post 479436)
Now I'm waiting for my Boundary/WeaponX COPS to arrive .... dreaming of big-gap goodness!!!

god, how long has that been now?

triple88a 11-08-2009 12:47 PM

Evan why dont you just toss in a tesla coil in there while you're at it :P


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