Have you checked the plugs? you might have a hairline crack in one. I also recommend the IW24's its the same plugs that HKS uses and relabels. If interested I can get the plugs for $12 each.

 

You deffinatly want to run the smallest gap pooible without a misfire which should be between .25-.30.

 

I get no signs of misfire, car just pulls like a biatch but my electronic Greddy boost gauge is acting like it can't keep up with how fast my spool is in 1st and 2nd gear, it is almost like a gear is stripped or something because sometimes it just pegs out and sticks, then I have to rev to build a little boost for it to come back down. I am assuming I would notice a big hit in power if I were misfiring. Do you think that a gap of .028 is too much and maybe I am having some sort of spark "blow out"? Could this be why I'm getting whacked boost spike readings that I don't even think are possible? I know it is not my mbc, because this happened occasionally with my previous controller.

 

if you had a misfire you would be able to tell. the car would hesitate. If your not having probs at .28 the go smaller to .26-.27. go until you have a misfire and then put it back up just above that.

 

oops I meant to say not my mbc, corrected

 

Actually, you've got it backwards

smaller gap = easier to fire, not as clean a burn

larger gap = more difficult to fire, cleaner burn

 

What causes the fuel mixture to ignite is a gas molecule passing through the gap in the spark plug as it fires. so if the gap is smaller it is harder to ignite because there is less room for the gas, but the spark is better. A misfire is when there is no gas between the spark plug gap when the spark plug fires thus no combustion. so you want to go as small as possible to get the best spark but not so small that you get a misfire.

 

I don't know where you get your information, but I can assure you you're mistaken. Misfires occur when the gap is too large, and the flame gets "blown out" (the pressures are too great for the current to jump the gap). YOU WOULD NOT GET A MISFIRE FROM TOO SMALL A GAP. If the gap were too small, it would not fire PERIOD, not just under extreme load / high boost.

 

all that matters is the best spark is from a small gap.

 

Not exactly. A larger gap will give a cleaner burn/more power, but is more prone to missing. This is why you want to have the largest gap that doesn't miss.

 

I got the IW24's for ONLY $ 7.50 each!!!!

 

Why do you need to adjust the gap? Theres a sticker on my hood that says IRIDIUM TIPPED PLUG ONLY "DONOT ADJUST GAP". Why are you guys adjusting the gaps? My IW24 has .4mm gap.

Does the IW24 have different gaps? or are they all .4mm? then you just manually adjust them? I was also told by my friend who import these plugs from japan that iridium plugs need not be adjusted. The IW24 are designed specifically for the EVO. He even showed me the DENSO application book.

 

Want to learn more about spark plug gaps, just go search online. There are tons of info out there that can help you.

And bigger the gap you can get away with without any problem is best for performance. The problem is turbo cars have greater pressure in the cylinder than NA engines making it difficult for larger gap to ignite. Thus, higher boost require smaller gap unless you run after market ignition system like MSD.
So if you've raised boost pressure on you Evo and have misfires, you should reduce the gap on the spark plug or add a more powerful after market ignition.

 

Oh by the way, too small of a gap can cause detonations. So a right gap is require to run at it's best. And how to find the right gap.
Do a search online for Spark Plug Gap. That should help.

 

mmmmmmm... so, where?