Hello Guys,

Who uses what on their STR, and what results if any..?.. plugs are due for change and wondering whether to upgrade or stay with OEM.

 

The spark plug industry is full of myth and snake oil infused misunderstandings. There is no such thing as an 'upgrade' when it comes to performance. A spark is a spark, it either lights the fuel or it doesn't.

 

Jags uses Denso in all its machines. The stock plugs are the best available.

 

Jaguar switched to the NGK iridiums in all their new Jag line up starting with the the XF but before they use to be Denso iridiums.

 

Inded Slick 50 springs to mind which is why i asked the question, also with modding, better intake, smaller pulley etc and possible remap was simply wondering whether any benefit in changing type or rating, thanks guys probably tackle an OEM chnage on my drive....

 

Thanks for the new plug info Jag79. Didn't know Jag switched to NGK.

 

I use pulstar iridiums in my xjr and I absolutely love them ...they are by far the best plugs I have ever used,and I can feel a big difference in throttle response and the idle is very smooth.The dealship charges about 17.50 a plug,and I paid 12.99 each for the pulstars...well worth it to me.

 

OEM type for the STR are like that

 

I replaced mine with denso

 

Denso iridium?

 

I just changed mine at 55K to NGK Iridium IX's. I noticed a pretty big difference in terms of smoothness, throttle response, and driveability. However that is probably not attributed to my choice of plug but rather that the car now has brand new plugs. If I were you go with either NGK or Denso's, but use the 50K mile ones and not the 100K mile ones (mid life).

Took about 3 hours after watching the how to in youtube and taking my time. My recommendation is get two 2.5 to 3 inch socket extensions (put them on top of each other plus the spark plug socket) and it should make the whole install process a breeze.

 

Yup