Toyota's responses to spark plug and transmission fluid questions

[greasefingers]

I wouldn

 

[boston_kevin]

I made no claims that Iridium is hotter (and yes, the same voltage through different metals can be hotter trying sending 10 volts through aluminum then 10 volts through platinum, platinum burns hotter because of less resistance through the metal... roughly 9.8 volts vs 10 volts output). What I was trying to figure out, which no one can seem to explain is why the V6 needs to have the plugs replaced at 30k miles vs the V8 at 60k (in my state) or 100k in other states.

This to me, seems a mystery... an engineering marvel or a mistake. Or perhaps the V6 and V8 fall into two distinct emissions classes? I have poured through the documents and mechanics all around me, and no one has a plausible explanation except for the VVTI. Both engines now share the same compression ratio, same intake, same ignition, same octane requirement... only difference is 2 more cylinders. So if both engines have the same combustion chamber stats, why 2 different plug types and intervals?

Any ideas??

 

[Koz]

My truck is in the shop. If I had it I would pull a plug and end the mystery! I