Does anyone know if the mid-pipe necks down to meet the factory cat? Most cat backs neck down but not ideal for those that have HFCs or test pipes. ALso, if you have this exhaust, please provide some feedback. Thanks

 

Yes it does neck down for the stock cat. It fits perfect. Mine have been modify to fit jdm bumper and 3" all the way. With the stock cat it sounded perfect, but now with all my mods it has become too loud. I was thinking about putting the stock system back on and install a down pipe with a electronic cut out on it. Like this one
https://www.evolutionm.net/features/newsitem.php?id=115

 

I was concerned about the neck down since I have a Perrin DP and HFC. The Perrin HFC is a full 3"at the flange so I'm not sure a mid pipe with a neck down is the right way to go....or if really matters at all. The HKS sounded good on some clips I've found, but I want to avoid serious highway drone if possible.

 

I have the hi-power with the stock cat. There is no drone at all on the highway. I love a quiet exhuast. You wont lose much power with the neck down. I guess it depends on how much power your goal is, and how loud you want to be.

 

My exhaust is loud as hell and I love it. I live in texas though, where all they seem to care about is cattle rustling. I don't really experience drone, just a nice deep note during acceleration.

 

you will have no problems mounting the perrin hfc to the hks exhaust. it may say its 3 inches but it still necks down at the ends. all the advertisments for it says that it can be used with the stock downpipe and catback. http://www.lancershop.com/customer/p...productid=1095

 

i have an HKS Carbon Ti catback on the perrin high flow cat. no issues with mating them together.

the "neck down" is minimal. really i think it is just the way they welded the flange onto the resonator pipe. i would say it probably takes at most 1/4 inch off the diameter of the pipe where it meets the cat.

the exhaust sounds amazing too. it's too loud when you're just cruising with it, it has a nice low, clean growl to it with some "burble". sounds very nice when you get on it too.

 

Any reason not to buy the HKS catback?

 

it necks down and is not a true 3 inch cat back

 

I have the carbon-ti and it is a neck down of exactly a 1/2 inch, I measured. At the point where it mates to the stock cat the diam is 2.5 inches for about a 1/2 inch in length. Its enough to hurt power as you can only flow as much as your smallest point, meaning the whole exhaust might as well be 2.5 inches. I just had it modified, with a 3 in flange and its now a true 3in exhaust. Love the sound of it and look of the angled exit.

 

I have the HKS GT extension Kit w/the Perrin HFC and the HKS Hi-Power exhaust.If fits perfectly and sounds awesome.Feels pretty strong to after the bolt ons.I know my DP and HFC are 3" and have seen that the exhaust is listed as 2.95".I really like my setup.I have heard nothing really negative about the HKS HI-Power exhaust.

 

Yes it neck down to 2.5 at the cat but what lots of guys don't know that it also neck down to 2.5 at the end of the muffler . Try to but a can of soda in there it will go at all. what I did to mine is that I cut the end where it meet the cat and made it 3 all the way. I also pulled out the 2.5 reducer from the muffler.

 

If I had to do all over again I will not get it. maybe AMS.

 

There has been a lot of threads bashing the HKS lately because its not a true 3". They dyno graphs I searched seem to indicate good gains but all these peeps talking about 2.5" at the muffler and cat are making think Greddy Ti