I recently purchased the Hks Carbon-Ti catback, it looks, sounds, and performs great, but I've read that the section that connects to the cat tapers to only 2.5 I really hope this isnt true, cuz if i had known i woulda gone ahead and purchased another exhaust that was truly 3 inches. I heard that if it tapers it basically kills any exhaust flow thats bigger than what it tapers down to, like if i purchased a 3 inch DP it wouldnt make a difference because of the way the cat back is made, I'm really just asking you guys to see if this true, thanks alot!

 

I swear I read this post 100 times a day

Are yo planning on 500 hp? if not, don't worry - your exhaust can flow more than your turbo can....

The taper is needed so it bolts to your stock cat (which itself hurts power if you want to get down to the nitty gritty of it all). But its so far downstream in your exhaus that it really makes very little feelable difference on the road (I have driven the same car with and without a cat and it was not dramatic at all - noticeable, but not dramatic)

You got a good exhaust, don't sweat it!

 

Most aftermarket companies have neck downs and resonators. The neck down is so that it will bolt-up to the stock cat.

On all our catbacks and turbo backs we don't have any neck downs.

What I would suggest it that you get a pipe with a flange on it and cut out your current reducer section. Then you will be able to slip the new one over it and eliminate the restriction.

Let me know if you understand.

Even if you don't plan on making 500hp it is still a restriction and that is why we don't make them like that.

 

the reduction in size will also change the tone or rpm at which it resonance and may or maynot cause more "drone" tones... I had an apexi dunk on my GSX and man it was sooo loud with a true 3 inch exhaust from turbo back, it got annoying after a while. Only time it was quiet was at idle, after that it sounded like a rocket, I must say it was a very intimidating sound

 

Will a 3 inch test pipe from ultimate racing bolt up to my hks exhaust? i want one Because supposedly it doesn't cause a engine check light.

 

all test pipes are identical in terms of causing a check engine light

 

um, no. Ultimate test pipe doesn't throw a check engine light.

 

does the AVO a true 3' system ? since it bolts on to your stock cat , im wondering if it tapers to 2.5 to bolt on

 

If HKS sucks, no one would be buying their stuff. Adam is right about what he said.

 

The B&B catback has no reducer in it. It is 3" all the way to where it connects to the cat. It is a little tight getting a wrench on the bolt head and nut around the flange to the cat.

Also, all test pipes are not created equal. The Ultimate Racing is different from all others. Buy one and you will see. No light because it is different than the others.


Brian

 

We;ve used the Ultimate Racing test pipe time and time again - NEVER any check engine lights. We've used the 3 inch version with Fujitsubo downpipe and cat back, for HKS I would have to check the piping, but Ultimate offers a 2.5 version as well whcih we sell.

Adam

 

The Ultimate racing test pipe matches up fine with the HKS downpipe. Should work with the Catback. But it really depends on what size your downpipe is. If you have a 3" downpipe, get the 3" test pipe. If you have a 2.5" downpipe, then you can get either one, unless you have a reducer in the inlet of the catback, then you should probably get the 2.5" test pipe.

So in this case with the HKS catback, I would think the 2.5" testpipe would be the way to go, unless you have the 3" downpipe.

Clear as mud. Okay.

Brian

 

Heard this from a friend: HKS = Hong Kong ****. Hahahaha.

 

Well your friend is stupid...and maybe you are too. HKS isn't even from Hong Kong...it's from Japan.

 

Only their intakes suck, their exhausts blow.

Sorry, couldn't help myself.