I’ve recently replaced spark plugs and realised on high boost after 1.5bar , the engine hesitated and jerk after hitting 1.5 bar even on half throttle , it even have backfire . On Low boost 1 bar had no issues . Decided to put the old plugs back everything was running fine on high and Low boost . Previously car was running on ikh24 denso plugs and replaced with the same ikh24 plugs . Engine set-up is stock internal , cosworth 272 cams , fic 720cc injectors , sard fuel regulator , hks intake , hks Ssqv bov , hks intercooler type r , hks twin oil cooler , walboro 255, exerdy heavy duty clutch , apexi n1 exhaust and hks evc-s boost controller . Reflashed map with Ron 98 . I’m very worried on what is the issue that is happening to the car as my old plugs are almost due for a change . Thanks for the help

 

I never ever had good experience with those plugs... Just run Oe NGKs...

 

Agree with Kiki.
BPR8ES or BR8ES are the best choice.
can be gapped to reduce spark blowout

 

but my car was tuned with ikh24 will there be any issue if i switch over to ngk?

 

are the ikh24 able to gap? Because car was tuned with Ikh24

 

I wouldn’t worry.
you can switch plugs after a tune as long as the gap is similar.
BPR8ES gapped is you best friend for smooth driving.

 

The 8 heat range is too cold for his power level. Need to stick with BPR7ES for copper or BPR7EIX for iridium. Assuming its not an Evo9 with Mivec of course.

 

its with mivec

 

Ok, then the BPR plugs won't work. You need to run OEM replacement NGK's.NGK part number is ILFR7H. The 4 digit stock number is 5245.