I was wondering if the HKS Hiper catback is a full 3" all the way through, as in no neckdowns for the resonator. I know about the neckdown for the cat but i mean downstream in the exhaust, are the resonators a full 3" inner diameter, cause I know of some catbacks that have a 2" resonator in a so called full 3" exhaust. Please reply with info, thanks

 

anyone?

 

i have the HKS 30th, but i dont know about the resonator part. Sorry.

 

i actually posed the exact same question a while ago to Mr. Dave Buschur, b/c he had brought up the topic that some JDM exhausts have narrow restrictor areas. . . and he basically told me to F--- off b/c i wasn't buying his product.

So, I have no answer yet. What i CAN tell you is that, after cutting off the 2.6 inch flange where it meets the cat, and having my Stage 1+ tuned by Shiv, it doesn't seem to make a difference as i was dynoing the same as all the other cars with the same mods as mine. But, of course, i suppose i could have had a stronger car to begin with, and the restriction is still affecting performance. . .

But, i plan checking it out eventually. Also, if you take a flashlight and shine it striaght into the muffler, it doesn't even look that that it itself is a 3 inch outlet. but who knows?

 

I dont know, but really i love my exhaust. a little taper or not...

 

The HKS does have a reducer and resonators in the system.

 

I think the question was, more specifically, if the resonator still allows a 3" passageway through the exhaust, or does it restrict the flow.

 

i have the carbon ti and the resonators seem to be the same diameter as the piping.

 

no it necks down to 2.5 to bolt up to stock cat as in with all jdm exhausts ice seen so far. why not get RnR's exhaust with one of the HKS canisters?

 

Right, but we're asking about where the resonater is, and whether that area of the piping lessens in diameter. Its already pretty easily noticeable that the tip where it connects to the cat is less than 3".

 

still not what they asked...they asked about the resonator in the midpipe.

 

sorry...posted after you did.

 

exactly, nobody botherd to look???

 

I just inspected mine. It does not appear it necks down at the resonator. It actually looks like the pipe stays the same diameter and the resonator is wrapped around it. There is a slight taper at the cat, though.

 

Now I'm curious if there's a neckdown inside the resonator. I just installed my hi-power cat-back a few weeks ago too.

If you're worried about how much HP you'll be losing due to a neck down, I doubt you'll even notice. The 2g DSM AWD RS*R exhausts used a muffler that with an inside diameter of 2.25", while the rest of the piping was 80mm or 3.14". That sure made things quiet. But guys were still running 120+ mph traps in the 1/4 mile and doing 400+whp with it, so it wasn't as restrictive as many thought.