Gap please

[jcarmich]

Hey just got some new fswerks spark plug wires and bought some Autolite XP104 extreme performance IRIDIUM PLUGS was wondering what the best gap would be, or was i dumb for getting such plugs. Seems like everyone loves the copper.

thanks
JT

[Sponsor]

[K Dog]

uh. Well. Quote honestly you should probably ask them, or have gotten our wires...


Additionally, yes, we find that the Motorcraft copper cores offer excellent performance and low cost, and with the ease of replacement on a Zetec, the copper's somewhat shorted life span is not a huge issue. I would run .055" on a bolt on car.

You CAN'T really gap Iridiums. You'll break the tip off with traditional methods. You can use a pair of needle nose and grab the strap, but it's difficult to be consistent with that method.

[jcarmich]

I could just send the Iridiums back, does it really make that big of a difference, of course the little things do ad up. Every one seems to give great praise to the autolite 103 coppers.

[whynotthinkwhynot]

Originally Posted by jcarmich

I could just send the Iridiums back, does it really make that big of a difference, of course the little things do ad up. Every one seems to give great praise to the autolite 103 coppers.

That's because we don't have a problem with changing plugs every 20k miles or so. Iridium and platinum plugs resist fouling, standard plugs do not. The plugs you bought will last for 100k miles or a little less, but definitely at least 4x longer than standard plugs. I'd use what you have. Spark plugs, although very important, don't really add a ton of performance to any engine. You might get 3 more hp by going to AR103 plugs as compared to XP, however those won't give that 3 hp RELIABLY. In another reference, you'll have 3 more hp when you put those in, but after 10 tanks of fuel (or less) you'll be down to only 1 more hp. As time goes on, deposits will build up reducing your "gain". You're really better off using what you have already gapped to the correct gap. Then you won't need to fiddle with it for a while.

I also prefer standard plugs because those develop deposits. It can be useful in determining engine problems. I only run those in the Focus. In the wife's Windstar I run platinums because those plugs aren't easy to change.

It's a give-take thing. If you don't understand what you're getting or giving up, then just put the iridiums you already paid for in the car and go for it.

[voortrek3]

I just put in a fresh set of Autolite 104's gapped to .051. They run perfect and like whynotthinkwhynot mentioned, I also prefer standard plugs on the Focus for the same reason...you can see how they are working by the deposits that they get.