I have a HKS induction kit fitted and have replaced filter but the new foam isn't as dense as the old. The replacement is an offical replacement product (150mm) from Amber performance but there is a marked difference between new and old.



There is now a very noticable sucking from the filter at idle that wasn't there before, i'm guessing due to the more open nature of the filter weave. Just want to make sure i'm not going to damage anything (either through poorer filtering or noteably increasing air flow).

 

HKS filters are available in different types of sponge............. usually, colour identifies the type of sponge (how porous it is), red, green, yellow........

 

Ah, all starts to become clear thanks. So with the increased air flow and decreased filtering should i worry?

 

I don't think it'll be a problem, can't say if there's less filtering.........
I run a sti type ra and my brother has a ltd ed 555 sti wagon, both with the green filters and are just fine. Infact, majority of HKS filters I've seen come with the green element.