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Discussion Starter · #1 ·
My car is due its 3rd sevice next month and what i want to know is, whats the best spark plugs to use on the ST? Mine is
slighty modified, running dsci race + and Airtec gen 3 intercooler. Am soon to be going to fit DS turbo down pipe and DS sports cat, so are the standard plugs ok? whats everyones thoughts on this and what plugs are you all running with
 

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A lot of people are running the RS plugs now and are happy with them.

I ran Nology's for a year but at the time places supplying them were sending out a tapered seat fitment which doesn't match the flat seat recesses on the ST engine and gives very little contact area for correct sealing. They were something like R4YS code whereas the flat seat ones shoule be ER4YS. I don't know if anyone ever managed to source the right ones for the ST.

They did solve misfires for some people but mine had been showing signs of blow-past, I took them out and refitted the standard ones and now running RS plugs.
 
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