For quite some time I've been wanting to swap the exhaust tip on my HKS Carbon/TI cat back. The tip for this catback is 120mm ID. (i.e. effing huge) and it is riveted (not welded) to the canister muffler.

I want to change it to one of two things:

1) a tip that reduces to 115mm ID so I can use the active silencer made for apexi exhausts (115mm ID tip)

or

2) a tip that bends down ("dolphin tale") like the re-amemiya cat back...

In order to do either of these, I figured I should find 115mm ID thin-wall steel tube/pipe, which I could then have flared to 120mm on one end so it will bolt up to the muffler (replacing the stock tip). however, i can't find pipe/tube in this size!

Any ideas?

---edit---

Made a diagram:

 

If you have access or know a machine shop that has a metal roller you could get some thin gauge metal and have them put a roll in the metal or roll the metal to the size you want. A simple weld or some rivets would hold it together.

 

ah good call. now that you mention it, i do know a machine shop that could do just that.

i was hoping to find some pipe in the 115mm ID size so i could make extras though. i'm sure other people with HKS cat backs would like to use the apexi active silencer as well...

 

Burns Stainless will have 115mm (about 4.5") tubing. It won't be cheap so I would suggest talking to a machine shop first.

 

Yes indeed -- about $45/ft plus shipping...

 

you could also take a piece of steel and make a spacer out of it....

so it would be 115mm apexi thing, 2.5mm piece of steel wrapped around it, 120mm tip

 

i thought about that but it seems like the ghetto-fix.

i think a whole new tip would be the way to go.

 

I'm having the same problem, can you please make 2? haha

 

haha yeah if i can get one made that works, i'll let you know. i owe you a favor anyway.

 

Hmm... I've got an N1, attached to a Megans Mid that I'm lookin' to offload...

 

Dont do the "dolphin tale" I don't think it looks good.

I have a magnaflow mid pipe with racing beat cat back and although it don't look as cool as an HKS or N1 muffler the sound is sooooo muffled i love it.... super nice for daily driving

 

So you want to either copy me or copy Dan huh ?

I'd recommend just swapping to a different catback, either the N1 or GT Spec. They're found pretty cheaply in the classifieds, after selling your HKS piece you'll probably be out maybe $100-150 and have minimal time wasted researching/fabbing and also downtime for the car.

 

I don't think swapping an exhaust tip will require any 'downtime' for the car.

I do like the look of the CF canister...i just don't like that the tip angles up (collecting water when it rains) and that the tip is too big to accept that active tail silencer...

I think I'll try to make a replacement tip first...then if I can't figure it out I'll swap the cat back.

 

Tom,

You can buy my JIC complete with silencer... Im in the market for a new exhaust

 

yeah or maybe i'll just steal it off your car next weekend.

 

ok an update!

so now that i'm with my car again, i checked out the exhast tip.

I measured it...

it's actually 120mm OD, 115mm ID.

115mm = 4.52"

So I ordered a piece of 4.5" mandrel bent exhaust pipe and I'm going to cut it so it's a dolphin tail.

However for the "reducer" tip, I need to know the exact ID of an Apexi tip...Can anyone measure the ID of an Apexi tip?