I posted this on the V6 board but not sure how many view that board.
Question is this, 2015 2.7 ECO is currently gapped at .30 as per Ford Specs, I am thinking of trying a gap of .28 to see if that will improve MPG and Performance
Has anyone tried a tighter gap on a stock engine.
It seems the first time I changed the plugs there were gapped tighter than the stock .30 gap as I checked and a .30 feeler gage would not fit, did not try any lesser gap though
Does Ford set the gap tighter from the Factory to give these engines a bit more pep. Would this have an adverse effect on the engine, predetonation knock, etc.
Thanks in advance

 

It’s .030” not .30. Huge difference. As for changing the gap by .002”, you will not notice a thing. All of you current plugs probably vary .004 to .006” as is.

 

I dont think you are going out engineer the motor designers that spec'd 30 thousandths on a stock motor.

 

.030 is pretty tight for a stock spec. They tightened it up since the first eb f-150’s came out. I’m not sure I’d go any less than .028 but no, you won’t notice a difference unless it happens to fix a misfire problem.

 

I’m curious why you’re changing the plugs. Due to miles? How did they look? Did the gap grow from the factory settings?

 

Ford spec is 0.028-0.030" for the 2.7L. Personally I always set the gap to the tight side for forced induction engines.

 

My H.O. 3.5 takes Motorcraft SP550. They come pre-gapped @ .028. I check the gaps before installing them, but they've always been right on.

 

More power = wider gap, not smaller.

You close the gap to correct misfire/'blowout' problems. For instance, you up the boost, you may have to close the plug gap (pretty typical). You may also have to run a 'colder' plug in some applications.

If anything, go to the top end of the factory spec. If you basically never go WOT, you can play with larger gaps -- but I wouldn't. It's not going to yield any appreciable gains, honestly. In a racecar, definitely. Truck? No way, Jose.

Buy stock plugs, install. Done.

 

Thanks all for the replies. I have 100K on the engine and have changed the plugs @ 45K. I didn't see any wear on the plugs I did pull out but they were not gapped @ 0.030, they seems tighter as feeler gauge would not fit @ .030. May be its just a mind thing but it did seem to idle better/smoother, and pep was better after changing them
Anywho, thanks again all