vasman

Hey guys. Since I have gone to a 10 psi setup, it seems that every 6-8000 miles my plugs fail (i.e. missfiring, engine skips a beat running on less than 8 cylinders). I have a catch can (Steff's) Weapon X cops (although my experience was similar with the stock cops as well), and mods as per sig. The plugs come out relatively clean without any unusual signs. I have tried Brisks and HT0, with similar results.
My plugs are spaced at .35 and are cooler than stock as supercharged.

I am told that they should be spaced tighter at .30 and that should take care of the problem. (Tillman)

Any thoughts/comments on this?

Thanks in advance.

Riptide

I've read that it's normal. Nothing you can do about it. I have no idea what the issue is or why this happens so often. Other cars with FI stock don't have those problems.

JDWalton

I'm in the same boat as you vasman, though I never heard about the tigheter gap. I have only had HT0s, but I notice if you look real close at the plugs your taking out, in my exp. anyway, that its usualy the elctrode has been pited or melted pretty bad. I REALLY REALLY wish someone would make a irdium plug for our heads, I have even sent requests to the manufactureres, as whoever did it, would have a corner on the market, but no luck yet. Till then left to melt the silver / platinum plugs. My car gets about 5 starts with my cams, till I notice it running different. though I can stretch the plugs a whole season, just doesnt idle the same.

SCCAGT

I changed mine at 10k, but only to avoid the dreaded broken plug issue. I am up to 23k now with 20k of those under boost. No problems whatsoever with fouling for me. No colder plugs, nothing. Stock coils to boot. Is your A/F good?

vasman

Jason,

I hear you. The Cams on your setup do not help either I guess. How would you explain though that the factory supercharged models do not have the same issue?

Their plugs are no different right?

I have seen on the Oriley's website for 29.99 a pop Roush plugs. They look exactly like the autolights HT0's but are almost triple the price. Do you think this may be the iridium plugs you are talking about? or just paying for the name...... (would not be surprised...)

vasman

I am reading 14.9/15.1 on normal operation 11.8-12 at WOT
As I said no abnormal deposits, plugs certainly not fouled.

siggyfreud

As the electrodes wear, the spark might not be coming out as strong. The biggest gap would be more prone to spark blow-out from the boost. Tightening up that gap will help prevent this, which is why Tilman said to close them up a bit.

BruceH

Normal. I'm on my third set of FRPP HT0 plugs. They are under $85 shipped from cjponyparts.com I've only used FRPP. Have read of guys only getting 1500 miles with Brisk which is why I'm sticking to FRPP.

I gap mine to .032. I use a .030 piece of stock and the strap springs back .002.

Unleashedbeast

are you guys talking about the old head style (plug change nightmare style), or new?

I have the new head style on my 2008 GT

dysan

I'm at 11psi on my e-force and I have my plugs gapped down to .032. I don't have that many miles on the car since I've installed the blower so I don't know how long they are going to last though.