NGK6510 LTR7IX-11 Iridium IX Spark Plug (4 Pack)

Never had one go bad, or foul. I've used this brand in a tuned Focus ST and stock Toyota 86.

The only plugs I run in my Big turbo focus ST. Multiple years with no issues.

Works as advertised

These are genuine NGK plugs. Works perfectly for the 2016 Ford Focus ST. One step colder gapped at .026" is exactly what the car needs if tuned with a bigger turbo upgrade. Engine runs noticeable smoother and exhaust note is a lot quieter with less crackles. Negative timing is reduced during hard acceleration.

It was exactly as described and they work for my car. not damaged in any way.

These worked great in my focus st. I was running a stage 1 93 octane tune and worked great for high boost applications. Highest I seen on my car was about 23.8Psi. They would hold there gap well !I would check the gap per application ( what your vehicle calls for ) before installing

Rule of thumb for tuned cars is to replace spark plugs more frequently than stock. So, I usually change my spark plugs every 3rd or 4th oil change with these.They’re not pre-gapped so you’d have to ask your tuner for that specification and gap them yourself which isn’t difficult. And, they’re also cheaper to get on Amazon even if you have to wait a couple of days.These plugs need a 5/8 spark plug socket. They don’t require anti-seize. And, the torque spec is 106 in/lbs for the Focus ST. If you don’t have a torque wrench, once you get the spark plug snug, you just turn it 1/8 more and you’re good. There’s instructions on the website if you need it.So, if you’re looking for colder plugs for your tuned Focus ST then look no further. You can also purchase the Denso two step colder plugs but that’s if you’re pushing high whp.

One defective plug! Cannot accerate, without engine cutting out badly. I was able to ID the defective plug and marked iy. I ordered another set of plugs else where. I've used NGK in all my cars and motorcycles and never had a bad one right out of the box.