SP413 (nickel alloy) $4.59
SP493 (platinum) $3.09

which is better, i used the nickel alloy and havent had any problems, but ive hear that platinum is a better conductor.

 

SP413 is $2.68 at Rock Auto. SP493 is $2.78 and is the recommended plug assuming you have a 4.6 VIN W.

 

yes i have vin W so the platinum is better for the vin W?

 

There's only one thing better than platinum, and that's iridium.

I mentioned the vin W because that's the only V-8 that year which Rock Auto lists both those plugs for. The vin 6 has no Motorcrafts listed for some reason and the 5.4 takes SP479's.

 

it has nothing to do with how it conducts. the platinum just erodes slower from the arcing of the spark which is why they last longer. Double platinum has platinum on both electrodes and a single platinum has it on only one. This is where it gets tricky cause u need to make sure the platinum is on the right electrode or you are wasting your money! To make things even more interesting there is a spark system called waste spark. Im not going to go into details but basically one side of the engine fires spark from the center to the side electrode and the other side fires from the side to the center electrode! so from the factory some used single platinum plugs but on different electrodes per bank! If you see a vehicle with half the number of coils as it has spark plugs that is a waste spark system eg. ford 4.2L and early 4.6L. In other words just go double platinum and you will be safe

 

Ahhh, heck with all that -

 

His 02 will have cops, so there's no waste spark.

 

I would just go with Iridium's, they've proved themselves to me. - I never had 16 mpg CITY before running them. I had to go w/denso tho. Motorcraft only had fine wires for the Vin M 5four engines, 4.6 and 4.2 models. Not for my L.

 

Dumb question here.... vin W?
How do I find out if I have a VIN W or other designation? On the VIN somewhere I'm presuming...

 

Vin W is a Romeo, vin 6 is a Windsor. 8th digit in the vin.

 

lmao yea before i knew "W" was for romeo and 6 was for windsor i was like hell yea i got a windsor! then i found out i have a crown vic motor :/

where the heck is romeo anyways, been meaning to ask that

 

Michigan, outside of Detroit lol. Not far from Windsor. - Maybe about 45 minutes..

 

If only it came to fruition...

 

JB.. did the Iridium's give you any noted performance increase aside from the MPG's?

 

No, not that I noticed anyway. No Dyno , factory tune, - so it's hard to tell.

BTW- That was city mileage, my city mileage and highway happen to be the same. I cruise @ 2200 Rpm and @ 76-79 mph highway so I get 16 mpg across the board now.

I just NEVER have had 16 mpg city before, it was usually 12 -14, I'm not easy on the go pedal either.