just been told my plugs needed changing after 5 k miles

is this usual for running a car on NF (100ml per tank ) they didn't look that bad just a thin layer of brown oxide, but don't know enough to question

Cheers

wrx 02, 280 ish bhp

 

yep, NF kills plugs if you use a lot, which 100ml per tank is.

 

cheers, so is it only the plugs it kills?

I was thinking about getting the car mapped using 100ml nf but now i have learned this may stay clear

 

Normally a set of heat grade 8's would last me 15,000 miles, I use 3mls per litre of NF. 5k is a bit early imho. there is no need to be concerned over the use of booster though least not in my experience although if used in excess as John mentions it can cause problems.

bob