brown.gavin•1mo agoProlific Poster

Just learned that gapping spark plugs closer than factory spec actually helped my turbo 3.5

I kept getting misfire codes on my EcoBoost after installing bigger turbos and trying to push more boost. After three trips to forums and a chat with a local tuner in Phoenix, he said to gap them down to 0.028 instead of the stock 0.032. I pulled the plugs Saturday, regapped them all with a feeler gauge, and the truck pulled clean through 5,000 RPM without a hiccup. Has anyone else experimented with tighter gaps on high boost setups?

3 comments

3 Comments

the_laura1mo ago

Tighter gaps are pretty standard once you push boost past a certain point. 0.028 is where my tuner had me set mine on my Focus ST after going to a GTX2867. No more blowout at 25 psi.

dakotawood1mo ago

Guess I should stop filing my spark plugs to 0.030 then.

amy_foster7927d ago

Yeah, but not everyone runs a GTX2867 or pushes 25 psi though. @the_laura that works for your setup but on a stock-ish turbo or lower boost you can get away with 0.030 or even 0.032 without any issues. Tighter gaps sound great til you start having misfires on cold starts or at low rpm.