hey guys i know that ngk makes spark plugs for our cars. which ones are recommended in the manual? is it iridium, or platinum?. i dont want to put something that would give me problems. I have a 04 sedan btw

 

they come with platinums, but a lot of people here run iridiums

the stock platinum plugs are supposedly good for 100K miles, but i think a lot of people that pull them out early notice the gap is off.

that said, i'll be switching to iridiums pretty soon

 

Yes, the stock plugs are platinum. But I don't really think platinum is an appropriate material for spark plugs.

Although Pt is very corrosion resistant (which is a big plus), Pt is also a strong chemical catalyst (which is a big negative).

Pt is often used in aerospace combustion systems and jet engines to ensure combustion light off. Pt helps to prevent flame out when its used in the flame holders. Although this may be good for a jet engine, its not necessarily good for a reciprocating engine.

The reason why is because Pt is a chemical catalyst and its effectiveness as a catalyst varies with the type of gasoline you put in the gas tank.

The plug tips naturally get very hot while in use. If on the intake stroke a simple hydrocarbon fuel is used, the fuel/air mixture will only light off when the ECU gives the signal to light the mixture.

But with Pt, since it loves to catalyze ignition so easily, it may light off the mixture before the ECU gives the signal. This is called pre-ignition. And pre-ignition is never good. It can reduce power and sometimes even cause ping.

Because the chemical formulation of gasoline varies so greatly across the country, the catalytic activity of Pt relative to the gasoline varies accordingly.

If you live in an area where good grade gasoline (aromatic hydrocarbons) is always available its not much of a problem.

If you live in California where the gasoline is a nasty concoction of ethers, alcohols, olefins and aromatics, the Pt plugs will react differently. In fact, Pt is much more reactive with ethers and alcohols than regular aromatics. So in California, you are much more likely to experience pre-ignition than in Texas.

Pt introduces an unknown variable that can only cause problems.

 

^ Are you saying get iridium or copper.?

 

He's saying (in the scientific analysis) your performance will vary depending on where you live.

Based on the results, pt may negatively effect your car in some locations more than others....

But long story short IRIDIUM would help you more vs Platinum. What do you guys think about Pulstar plugs for NA applications? Ive been thinking about those ones too since I don't plan to boost for at least another year or so

 

Search Pulstar on here and you will find negative reviews, including plug failure and engine damage.

 

hmmm, i think the dealership recommends the ngk platinum.

 

I've heard Nissan is no longer using Pt plugs in their newer engine designs.

 

oh i see, so you recommend using the ngk iridiums as well?

 

Probably, but i don't have any experience with them. A search will probably yield the best results. Many others have gone through this evaluation before and in great detail.

 

it's always good to pick Tony's brain! Thanks for the info.

 

Awesome info Tony!

 

My tuner is still a big fan of NGK copper plugs. He had bad luck with two VQ's and IR plugs. Good news is that copper plugs are low price. Bad news is that they don't last as long. Since I run my car so hard anyway I just change the plugs once a year.

 

^ Which coppers do you buy?

 

If you want regular NGK copper, this is it for VQ35:
(LFR5A-11, NGK part# 6376, should be $5.62 a piece, pre-gaped at 0.044")