ok, i've done searches, i keep finding conflicting answers

DOES the hks exhaust (any of em) taper down to meet the cat at all? does it taper down for the resonator??

please help, i'm going nuts.... any other specifics on the pipe diameter i should consider??????

 

HKS DOES taper down for stock cat.

 

how much does it taper?

and the resonator?

 

It's not that big of a taper to where your gonna be choking the car or anything. My car made 279 awhp with the HKS downpipe, carbon-ti and rs intake.

Oh....and I had the stock cat on it too.

 

the HKS is nice, I like it alot, but would not buy it becasue its not 3".

 

It tapers down so that the flange is the same size as that on the stock cat. I would say the piping tapers down to a hair over 2.5".
So the flange is the same size as the cat, there is about 1/2" of the 2.5" pipe, then it expands to 3" quickly.

 

there is taper down to meet stock cat, but no taper at the resonater

 

hmmm i really liked this exhaust would it be good for around 400whp because thats all i ever really plan on making.........?

 

The flange size at the cat is around 65mm, the same as the hks downpipe.

Here is a picture of the neckdown:

 

So the inside of the resonator does not taper down at all? I forgot to check mine before I installed it.

 

The HKS DOES taper down to meet the stock cat.

If you plan to swap out the torbo, than the HKS exhaust may not be the diameter you are looking for. If you are keeping the stock turbo, the HKS diameter of 2.65 is plenty for flow.

You NEED 3 inch for an aftermarket turbo, you can use 3 inch for a stock turbo, but there will not be any noticible gains between the two sizes on the stock turbo.

Remember, 3inch needs more work to fit, the HKS system is a direct replacement with NO clearence issues at all.

MY $.02

 

Thanks for the info guys!

i thought the HKS exhaust was 75 mm which was something like 2.95"??? or are you talking about the taper size now?


question part 2:

if i were to take it to a muffler/exhaust shop to get installed, could they actually widen the taper to match the rest of the catback? i heard that this is done pretty easily, but i worry about reliability issues?

i have a 3" cat delete; would there possibly be any problems with the HKS catback?

 

dude you will be fine, seriously. Im running HKS 30th anniversary catback with 3" UR test, and 3" UR downpipe. The only neckdown is at that one spot, and its not going to choke your performance to anything that will be noticeable. If you are worried about it SOOOO much, then yes you could go to a muffler shop and have them cut that neck down off and reweld a new little peice of 3" pipe and a new flange there in its place. Problem solved, but I doubt that many people would be worried about it enough to do that. Take it for what its worth. There have been many threads on this subject in the past as well. A quick flip of the search button will yeild many of the same answers people just posted FYI.