Does spark plugs help increase HP?

 

Do spark plugs increase horsepower? No.

 

no

 

Thank you for your reply. I have a stock motor with only a CAI kit. Would I notice any better performance with more expensive plugs?

 

No

 

Why did Nissan/Infiniti choose to include iridium plugs on the HR equipped Z's/G's?

 

Probably for the fact you have a little more reliable spark delivery. With higher reving engines you have more of a chance to blow out your spark. If the plug is more efficient at spark delevery then you will have less missing and all the associated problems. But this is more of a WAG ( Wild @ss Guess) than any thing else.

 

Iridiums just buy you longer service intervals. They don't really perform better than coppers that are in good operating condition. You just don't have to replace them as often. Honestly, basic coppers work just as good as iridiums as long as they aren't old. The tip will wear out over time and your gap will start to stretch a bit on coppers so I usually drop a new set in once a year and the gap difference is almost non-existent. It's cheap, it works extremely well and takes virtually no time to do. Stay away from platinums since the platinum puck can fall off and the results could be quite unfortunate. Make sure you gap them correctly, replace them once a year and you'll have best perfromance.

Obviously, if you put a lot of mile on the car, consider changing them more often. I do about 12-15K on mine per year.

 

HR motors coming with Iridiums stock...pretty cool huh?

 

go with denso or NGK iridium...although the NGK foul out allot less than the Denso. It does make a difference, its not like a bolt on hp mod, but it will help your car run and perform allot smoother. And in high HP applications the denso's have been proven to produce some HP... check out their website.

 

nope.

 

NGK Iridiums: Stock# LFR5AIX-11 ($7.60 per plug)

 

spark plugs light your fuel at the right time, bad spark plgs can under spark or spark at the wrong time there by decreasing engine efficency..... in other words more fuel consumption