Spark plugs

[Caldean]

Hi just looking for some advice i have fitted a new set of spark plugs in my mini cooper s r53 facelift do you think it safe to run a step colder it hasnt any engine mods apart from a cat back stainless exhaust system the plugs i have fitted are bkr7 eix will this cause any issues as appossed to using bkr6eix these are both irridiums engine is stock any asvice on running the 7s wud be appririated or shud i change back to 6s

[jdl_1967]

I run BKR7EIX in my R53 JCW with no issues. You're safer with a cooler plug than a hotter plug, but if too cool, you may get a fowled plug.

I usually stick to the suggested heat range, but if you take one out and it's the right colour and not blackened up, they'll probably be fine.