Can anyone tell me what the standard plug will be in my '04 Sti (Type UK)

and what would be the best upgrade if running around 400bhp? (part numbers please )

Also NGK or Denso?

Iridium or Platinum, have read on manufactures/suppliers sites that Iridiums far outperform and outlast the Platinum variety but have read other Snet forums stating the complete opposite totally bamboozled!!

Thanks in advance,

Dave

 

They should be NGK pfr 7b.

These are more than adequate for 400 bhp

 

Standard fit plug is the NGK PFR6g
You will need to upgrade to at least NGK PFR7b or equivalent iridium with a gap of 0.65-0.7 mm as you'll be running a lot of boost to make that kind of power.
To go from standard to a safe and reliable 400bhp is going to cost you a lot of wonga!
JohnD

 

Thanks fellas

Does anyone have an opinion comparing NGK to Denso's?

 

I used Denso IK22's (heat grade 7 equivalent) a while ago but was "warned" off them by respected opinion regarding reliability. I had previously used Blitz (NGK) iridiums with no problems at all but found the ground electrode eroded noticably over the 15k miles used. If you're aiming for that kind of power, you may need to change them quite frequently, maybe 7-8k miles?
JohnD

 

Tell me about it, spent wonga retained wife .

I've gone for the PFR7b's (double Platinum) but was wondering how long I can expect them to last?