When in boost, I have my AFR running on 11.8, starting from 100kPa.

But when I'm running 11.8 the engine is running jerky / hassitant /shocks. When setting leaner (11.8 to 12.0) the problem stops and the engine is running smooth.

I do have a wideband which is (last week) calibrated.

Why can't I run richer than 12.0 on my 2002 1.9 NBFL engine?

 

What is your spark plug gap?

 

1.1 mm

 

Should be at .71mm for turbo. The increased air/fuel density makes it more difficult for the spark to jump the gap with our weak stock coils so it needs to be gapped down. This may or may not solve your problem but it will solve others you would have eventually. It makes a big difference in spark blow-out.

 

Sparkplugs "regapped", this weekend trackday, I will let now if it worked.

 

11.8:1 at 100kPa is REALLY rich.

 

Yes things are a bit better but I changed the afr to 13 for the low rpms. It seems that at higher revs, the issue is not present.

Can I upgrade the coils to better ones? Is there a brand/type that is plug and play to my ms3?

 

https://www.miataturbo.net/useful-sa...writeup-12704/

 

The Toyota COP's seems to do the job

 

cool story bro
did you figure out a mounting solution for toyota cops on a vvt engine or are you running gm or other coils?

 

Toyota cops from a yaris, 16 euro on ebay. I will post some pics tomorrow.

 

We've found LS coils to be a bit hotter than Toyota pencil coils, and ones like our IGN-1As are hotter still.

 

It won't cause jerky engine performance. In fact, I know from personal experience that you can run N/A motors well under 10:1 and they will continue to run smoothly at WOT.