Iridium Spark Plugs?

[Killa B]

Im about to do a tune up on my 89 NA ive noticed a lot of guys on the forum say they run iridium plugs but on the horizontal pillar in front of my radiator there is a warning label from Toyota saying to only run platinum tipped plugs? I don't know much of the difference between the two im guessing its just a different type of tip. Will it not hurt to run iridium plugs? I just want to get the best materials to do my tune up.

[btwilson86]

These cars came with single platinum plugs, meaning 1 of the 2 electrodes are platinum. Iridium plugs are similar, they have a platinum negative electrode and an iridium positive electrode for longer life. If you want something that is more likely to give you a better spark over OE, then run a double platinum (both electrodes are platinum). They are cheaper than iridium plugs, too.

[MA70-3.0GT]

agreed, mine came with double platinum & they've been great & I'll be fitting them again when it's back in one piece *again*!

[cre]

I change my spark plugs whenever I change my oil (2 to 3 times a year depending on how I'm driving). The longest they'll stay in there is every other oil change. Not a whole lot of point in using iridium if I'm not leaving them in there for two years straight... Not a lot of point i using platinum either. I usually run NGK's copper plugs these days and I haven't noticed any change in performance or mileage in any of my cars (I run double platinum in my wife's car because unless she reminds me I don't service her car regularly).

[Killa B]

Okay thanks guys I'm running single platinum tip Bosch plugs right now haven't had any problems out of them at all they've been decent plugs just that time to change them out. One more question my spark plug wires get pretty hot after driving especially on the interstate, someone told me I should try running 8mm wires would this help with efficiency at all?

[MA70-3.0GT]

The heat in the plug wires is most likely just heat soak from the engine fella. There's about 50,000 volts going through them but barely any amps so I'd have to believe they're not heating from the load

AFAIK the size is just insulation thickness as opposed to the conductor being any thicker too (someone'll correct me if I'm wrong of course)

[cre]

Some wires do have thicker conductors. Most of Taylor's wires have a thicker core than some of the more common retail wires.... but you have to build them custom if you want them for the 7M. One thing to remember about ignition wires is that the hotter they get the higher the resistance of the wire. The thicker insulation helps a LITTLE here but it's not enough to justify switching over. If the wires are crap then replace them, if not then don't worry about going all out and buying the top of the line in the racing world.

[Killa B]

Okay thank you ill just stick with the cheaper brand then