Hi all,
In 2nd gear I'm getting hesitation when I climb to redline. It doesn't happen all the time, but it happens enough that it's annoying. Currently I have a 2.8" pulley on the car, it's making around 17.5 lbs (120 kpa on stock guage) of boost, which I believe is causing my spark plug to blowout.

This being said, my gap is 0.040 as recommended by a friend, I think this is way too high for 17.5 lbs of boost, would you agree? I believe the best range for this pulley would be 0.032 to 0.035, is that correct? I believe I will just split the difference and go for 0.033, suggestions?

Thanks again!

 

i don't remember exactly what i had my gap at when i was on a 2.8, but .040 is definitely too much. theres a fine line when gapping a plug, the larger the gap the better and 'fuller' the burn. but too much and you'll get blow out. try .035 and go from there

 

Thanks, I thought 0.040 was a bit too aggressive, I wonder how many misfire's I'm getting, can't wait to trim the gap down after work...

 

I'm at 32 with mine, 2.8 pulley

 

I'm hearing .032 a lot, i think that is where I'll start.

 

you want to have it as big as you can but without blowout. start at .032 and work your way up till you get blowout then back it down just a little.

 

I was at .032 and .033 and car ran like a gem with the same exact mods

 

I run .040 on my 2.8 setup, but I don't run near as much boost as you...I hit 16lbs or so since I have some port work. No spark blowout.

 

****, I have to run .028

 

lol yeah i'm .026/27 here

 

Well, going down to 0.035 made a massive difference over 0.040, I am actually getting almost 18.5 PSI doing runs last night. Seems quite high for a 2.8" pulley, I was hitting over 125 Kpa. Perhaps given that I live on an island that's almost 99% sea level, that may account for the increased boost?

Seat of the pants difference from the change down to 0.035 was incredible. I felt the car was being a dog before, this fixed everything. I still feel like a smaller gap is warranted from everything I'm hearing. Probably going to open her back up and get her down to 0.032, I feel there may be a bit of blowout as redline pulls to 7K in 2nd gear were a bit suspect around 6K RPM.

Spark has an amazing effect eh, especially if the gap is screwed up and you fix it!

 

Oh yea, I also noticed, that after lessening the gap from 0.040 to 0.035 my idle is better and my idle RPM has increased by 10% (previously idled at around 900 RPM, now idling just over 1,000). What does this mean?

Cheers!

 

i'm throwing a misfire code with the same plugs and nearly the same mods. i don't even think i gapped mine i thought someone was telling me u don't gap platinum plugs or w/e...

 

boost went up because more complete burn and higher cylinder pressures and a restrictive exhaust not letting all of the pressure out.... get rid of that stock exhaust...

 

These plugs are copper i believe. They are fine to gap, you'll want to gap them asap, the difference will be huge. I'd gap them to 0.032 right off the bat.

 

Well, 0.032 is no good for my car. I gapped down to 0.032 and I got a check engine light for misfires which was accompanied by a really rough idle. I re-gapped back up to 0.034 and everything is great now, no blowout, no misfiring, no rough idle.

Lesson: 0.032 isn't good for everyone, and you will need to find your own sweet spot unfortunately.

 

well i replaced my plugs last week and they are the same ngk bkr7e's as before... they come gapped to .032

 

Mine came gapped at 0.045, I had to tap them down a lot until I got to 0.032. Are you certain? Also, the gap they ship with can easily change from the shipping process, did you double check? Vibrations and what not from shipping could mess with the gap.

Ultimately, the gap they come with, doesn't mean much anyway...

 

I remember my SS/SC was really finicky about gaps .... .35 and up the car ran like ass.... .30 was where i ended up .

 

who called it? this guy. lol

 

My car doesn't seem to b picky at all, I've tapped from .35 all the eat to .27, and never noticed a difference, any reason why?

 

lmao

spark plug gap wont make it idle higher you have another problem

your not supposed to

the gap wont change during shipping