I own a 2004 sti running around 340 BHP and have found that the car has NGK PFR6B spark plugs.
The engine is standard and just has a tek3 remap.
Should I run PFR7B's instead? or can anybody recomend a better equivilent?
If I do upgrade the plugs will I notice any difference in power/performance?

Thanks in advance

Paul.

 

When you say the engine is standard, are you saying you are running the original exhaust system? If you are I'm surprised you have 340 with just a re-map! Or was it PPP?
PFR7b plugs are fine for what you've got. If you have 6b's at the moment, they won't be the original set, as the factory fit is PFR6g
JohnD

 

Thanks John, Sorry car has a full de-cat system.
The 6B's are quoted in my service manual and were replaced with new 6B's by subaru chelmsford on my service.??

 

A main dealer (Days in your case?) would usually only stock standard parts. You would be safer with the 7b's - gapped to no more than 0.7mm as you're running a higher boost level.
JohnD