spark plug gap (I've searched)

[fr0st]

so i swapped my plugs for NGK IRIDIUM ZR6FIX-11 gaped at .42 from what i measured. an thats factory.


some say its cool at .42 and some say at .38

so whats the best? i tried them factory gapped at .42... will i see any diffrence if i try it at .38 ?

Fr0st

[Alejo_NIN]

i actually think is .32 if i'm not mistaken
.40 seems high

[magnumP5]

The "-11" at the end of the spark plug designation is actually the gap (those are pre-gapped plugs). The "-11" refers to 1.1 mm or about 0.042 in I believe. I am currently running the ZFR6F-11's with no problems but most people say that gap is too large. I keep trying to find some regular ZFR6F but every place I've been to has to special order them.

EDIT: In case I didn't clearly state this most recommend between 0.028 and 0.032 gap for the MSP.

[orng1]

The bigger gap will make a bigger spark which will help make a complete burn. But with that much gap it's a lot easier to not be able to fire, as boosted cars can blow out the spark. I keep mine at around 30-32.

[xelderx]

I gapped mine down to .028 after having some misfire issues. Car runs great now.

[BOOSTR]

The Mazdaspeed Protege Owners Manual Addendum states spark plug gap is 0.7-0.8mm 0r 0.028-0.031in.

I've just put in the replacement plugs w/o gapping per the manufacturer, but after reading that little manual, I am going to pull them and check the gap and close somewhat if needed.

The 0.044 that you see on autoparts websites is meant for NA. Wouldn't be the first time the MSP info was incorrect.

[shane02pro5]

.025 13psi

[Knox Joe]

I gapped mine down to .028 after having some misfire issues. Car runs great now.

+1

[fr0st]

i lowered mine to 0.31 now.. couldn't go drive it to test it out, its raining like a mofo here..

[magnumP5]

I should really bring mine down. What range plug are you guys running? According to Crossover Auto we can run ZFR6F for 10 psi and lower at 0.028-0.032 but I've seen a lot of guys run the ZFR7F's at stock psi.

[fr0st]

I should really bring mine down. What range plug are you guys running? According to Crossover Auto we can run ZFR6F for 10 psi and lower at 0.028-0.032 but I've seen a lot of guys run the ZFR7F's at stock psi.
maybe how cold the climat is in your neck of the woods has a link to what plugs you can run..

[magnumP5]

maybe how cold the climat is in your neck of the woods has a link to what plugs you can run..
That makes sense. It's neither too hot nor too cold where I am most of the time so probably stock range is good for me. Now I just have to get out and buy some new plugs.

[1moreMPH]

i switched from the stock plugs, to the ZFR7F's pre-gapped from Crossover, and gained up to 12hp across the band haha. gap should be .28-.32 from what ive heard. And at 10psi it's a good idea to go a step colder. Im at 8psi with a spike of 11 and the car hammers down the road.

[evilmonkeyMSP]

OT, kinda....what are the plugs supposed to be torqued down to when installing them?

[fr0st]

OT, kinda....what are the plugs supposed to be torqued down to when installing them?

i have a phobia of over tightening things.. i broke too many bolts and shit..

and i need to get a 20 lbs torque wrench.. my 10 -150 is too big for fancy jobs..

[Alejo_NIN]

i torque the spark plugs by hand
usually when it stops turning i just do a 1/2 turn extra and that's it.


once i felt like i was The Hulk, then broke a strut and all the fucking gas came out....that day i felt overpowered

[orng1]

I too am afraid to over torque them. I've seen a lot of people mess up the aluminum head. I usually just hand tighten the plug then a small maybe quater turn.

[1moreMPH]

i believe it's supposed to be torqued at 20 ft-lbs. And while ive never actually changed them all on my own ((loser)) everyone ive seen just tightens/loosens/tightens until it seats snug, ~1/2 turn past hand tight. makes me nervous too though...

[magnumP5]

i believe it's supposed to be torqued at 20 ft-lbs. And while ive never actually changed them all on my own ((loser)) everyone ive seen just tightens/loosens/tightens until it seats snug, ~1/2 turn past hand tight. makes me nervous too though...
Whoa there! I always thought it was like 11-14 ft-lbs or something because I remember having a hard time getting my torque wrench to register.

[BOOSTR]

Looks like NGK is liberal on the pre gap on the 3271's. Never seemed to translate into a pefromance problem for me with the wider gap. Even so I'm going to get some different plugs and try a 0.030 gap and go from there. Hopefully I'll discover some hidden power.

Hand tightening plugs is fine. Torque if it makes you sleep better.

[fr0st]

Looks like NGK is liberal on the pre gap on the 3271's. Never seemed to translate into a pefromance problem for me with the wider gap. Even so I'm going to get some different plugs and try a 0.030 gap and go from there. Hopefully I'll discover some hidden power.

Hand tightening plugs is fine. Torque if it makes you sleep better.

the reason they say "dont touch the gap" is by fear or damaging the little electrode..

[BOOSTR]

Switched to a lower level NGK #4291 plug and gapped it at 0.031 inches. Seems to have smoothed out the upper RPM acceleration a bit, not that I had complaints with the other plugs. Didn't seem to make a bit of difference off the line or in the lower RPM's. The car ran strong before with a liberal gap. Oh well at least I know its within the recommended gap range now.