I'm breaking up on the top end. Spark plug gap recommendation please?

[Suprapowaz!(2)]

I'm running Autolite copper 3922's @ 0.031 gap.

16 psi on a Garrett T4 60 trim. AFR's are at 11.7.
Shell 93 octane gas.
Car is breaking up after 4200 RPM to redline.
I have not done the ignitor "mod".

Should I close the gap on the spark plugs? What would you guys recommend?

 

[stevenr816]

I usually gap .028


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[jetjock]

Why do you think it's spark related?

 

[Suprapowaz!(2)]

I'm guessing cause the fuel mixture is good. Could it be something else?

BTW, I didn't have this issue when I was running 12psi. I bumped it up a little and now it's here.

 

[Suprapowaz!(2)]

Fixed.

I pulled all the spark plug and checked the gap. They all ranged from 0.035 - 0.039! Last month when I put them in I didn't have a spark plug gapper tool, so I used a feeler guage to gap them. Turns out I did a sloppy job and gapped them too much. I found my spark plug gapper and re-gapped them to 0.028. I took the car for a spin and the break up is no longer an issue.

 

[stevenr816]

Awesome


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[gsxr141]

kind of a related question.... i finally installed new plugs, but i went with autolite 3923's. i see that everyone is using 3922's. should i switch to those?