I only found one thread and it was 7 years old and not what I was looking for, any help would be greatful.

Well my 03 evo 8 has been backfiring a decent amout and im getting annoyed/ worried, its tuned for the cutout, and backfires a decent amount full throttle between 4000-7000RPM, and im not sure if thats harming it at all, and when i have the cutout closed it backfires less, any thoughts?

main mods for reference: 58mm turbo, 750cc injectors, 272 cams-

 

first thoughts.. did you get it tuned?

 

plugs?

 

yeah its tuned by kunal. ill check the plugs tho, whats a good brand of plugs for reference?

 

NGK brp8es gapped at .028 and you should be good.

 

+1 plugs

 

Mine backfires only when I shift gears with the cutout open at full throttle during shifts. Other than that its pretty good about not backfiring.

 

Plugs

 

is there any other common cause of excessive backfiring? - thanks

 

Under WOT, misfire is the easiest cause. Go with the 8's like stated above.

 

mine only does it when its cold out and i dont let it warm up

 

Spark Plugs is my first advice.

 

Go to napa they will have your plugs vince.

 

allright thanks everyone

 

maybe its fuel thats not being burnt up? do you have a air fuel ratio gauge

do a boost leak test