nOOb question about platinum plugs

Blue Bomber · #1 (**permalink**) 10-10-2008, 01:53 PM

why cant you use platinum spark plugs. i know you can't, i just wondered why.

jarod17 · #2 (**permalink**) 10-10-2008, 06:41 PM

You just opened up a hornets nest with this one

So I will respond first. I have never had a problem running platinum plugs in any of my trucks. I have never gone beyond regular platinums so I have no input on those. At the same time I never really noticed a performance increase with platinums but I noticed that they did not run as rich on some of my trucks.

FTE Ken · #3 (**permalink**) 10-11-2008, 07:56 PM

Plugs should make no difference on A/F ratio since that's a function of carb jetting or EFI tuning. Maybe a more complete burn, but that's not because they are platinum... you'll get a better burn with new copper plugs when you change them (when gapped properly)

The biggest thing you gain with platinums, of the same heat range, is they last a lot longer because they don't suffer from nearly as much gap erosion, meaning you don't have to pull them to regap them periodically for optimal performance. They do this because platinum plugs can use a finer wire and the spark can jump the gap easier from a sharp small metal tip than from a fat flat tip. You can count on about 2-3 times the service life with platinum plugs. Use of platinum plugs is how manufacturers have achieved 100,000 mile change intervals.

Blue Bomber · #4 (**permalink**) 10-13-2008, 11:03 AM

sorry guys, i ment to put under boost in there. so the question is really why cant you use platinum plugs in a forced induction engine?

Blue Bomber · #5 (**permalink**) 10-14-2008, 10:08 AM

bump......

FTE Ken · #6 (**permalink**) 10-14-2008, 10:35 AM

It depends on the application. Platinum can be used provided the gap is correct and there is enough output from the coils. Resistance goes up as cylinder pressure goes up, and platinum doesn't conduct as well as copper (for instance) so higher output is sometimes needed. HT0 plugs used in almost all 2004-2008 supercharged 5.4Ls are platinum plugs.

Blue Bomber · #7 (**permalink**) 10-14-2008, 11:20 AM

so copper is best for low voltage systems?

FTE Ken · #8 (**permalink**) 10-14-2008, 05:27 PM

Iridium plugs are probably the best option if price doesn't matter (they run about $15 per plug). Doesn't conduct as well as copper but lasts a lot longer, while conducting better than platinum. What vehicle has the blower?

Blue Bomber · #9 (**permalink**) 10-15-2008, 09:51 AM

im tempted to put a junkyard turbo setup on my engine after a good rebuild or engine swap. my friend want me to throw a 300 in it. im just trying to sort everything out before i make up my mind.

2000BLK54 · #10 (**permalink**) 10-21-2008, 10:50 PM

I know a lot of shops run regular copper plugs in their cars. Run them in my truck, friend runs them in his turbo pony, just about most will suggest using them because they work and cost $3/plug. Think the main thing against platinum plugs is that if the engine starts detonating the ground strap won't burn away as quickly as a copper plug's would. If the ground strap goes fast enough then the cylinder shuts down and saves the piston.

Blue Bomber · #11 (**permalink**) 10-22-2008, 09:53 AM

thanks for the info. hows that methanol inj. work for ya?

2003F-350SuperDty5.4 · #12 (**permalink**) 11-21-2008, 01:22 AM

One thing to remember for every 50HP, lower the heat range of the plug 1-2 steps