Emrys

What's up everyone? This is my first post to this forum, although I've already read quite a bit between this forum & clubwrx.net. Great information on both of them.

First of all, in the grand scheme of things, I'm planning on a Cobb AP, downpipe, and borla hush exhaust. Would stage 2 93 octane map be okay to run with this setup?

Having a few problems finding out which downpipe to get. I'm thinking about getting rid of 2 of the cats, and leaving one, but I don't know which one yet. I know the one on the uppipe will be most efficient 'cuz it heats up the fastest, but probably provides most back pressure. The 3rd cat probably provides least backpressure & best spool time but doesn't heat up as fast. I want to keep at least 1 cat for enviro. purposes.

So I guess a good moderation between the two would be to keep the second cat. But I haven't seen too many downpipes w/cats on them. The most popular ones are catless.

So, should I keep the 1st cat, and get a downpipe that deletes the 2nd & 3rd cat, or should I gut the uppipe & get a downpipe that keeps the 3rd cat? That would also make it easier for the Borla hush to bolt up to, wouldn't it?


One more question while I have your guys' attention. I know the divorced & bellmouth designs are better than stock. If the setup that I described earlier in the post is as far as I'm going to take it, do I need a bellmouth or divorced design? I've heard they're really only good for extensive modding. thanks.

slvrsubywgn

iTrader: (7)

First of all, welcome to i-club!

If it were me, I'd definately get rid of the cat in the uppy, no questions asked. It makes a huge difference, and later on down the road you run the chance of the cat getting old, disintegrating (as mine did), and ruining your turbo, and even worse, your engine. Most people, as far as I've heard, if they're keeping a cat, keep the last one, for the same reason you said...minimal backpressure. But I don't think you're gonna be passing smog with just one cat, so I don't understand why you would keep it.

'Need' is all perspective. I've got a bellmouth dp and I wouldn't trade it for say, an hks downpipe, or any other straight dp. The bellmouth design really accentuates the turbo's spoolup. I can't really say anything for the divorced dp, as I have never owned one, but I've only heard good things about them. I would guess that they are every bit as good as bellmouths, considering their design. I would recommend checking out the reviews section at the top of the page and see how actual owners like them and compare the two that way.

Smitty

Emrys

So having one cat is pointless? I figured it would do at least do a little bit. I don't want it to smell overly rich when sitting idle and I thought that most cars only have 1 cat on there. . . so I figured that would have been fine.

Oh, with the bellmouth, I heard that it will make a chirping sound or sound like a cricket is in your exhaust. I've only heard very little about this, so does anyone have any feedback? Does the divorced downpipe make the cricket sound too? thanks.

-Rob

bpang1

iTrader: (25)

^^^That's the turbo spooling.

OK well first of all nice first post...most guys post some noobian stuff like "what kind of blow off valve should I buy".

I say buy one of the catted downpipes available on the market like the Helix... click here http://www.gruppe-s.com/Subaru/subex.htm ...scroll down to the Helix Catted DP...click it...read that it will pass CA Smog.

The bellmouth or divorced debate is ongoing but with just a stage 2 setup it should be fine. You SHOULD however check with Cobb to make sure you can run AP Stage 2 with a catted DP (though the Helix one is much less restrictive than the stockers).

BTW check with other Borla Hush owners to see if you should order Kartboy hangars...I think one of my friends with that exhaust is using them but am not sure.

cdawg

I agree 100% that you should get rid of the cat in the up pipe, and go with a catted DP and catted MP. However, I have read instances of folks passing CA smog (sniffer) with just the midpipe cat. If you go with a catless UP and DP, you may fail visual. Some folks will gut the stock UP so that it looks stock when it is on, but is not restrictive.

Emrys

Yea, I was thinking of just gutting the uppipe, instead of buying an aftermarket one. I figure that it can't be that much better. I haven't done any research on how to gut it, but I heard it's a *****. I'll figure it out when I'm getting ready to do it. I'll have to buy the CEL fix though, right?

You know, I was looking at the helix dp. Aparently it's really popular amongst subaru owners. I see everyone talking about it. Well, that one and the indivia one. But that helix pipe is wicked expensive! Is it really worth that much? I was thinking of getting a cheap bellmouth dp from ebay that deletes the second cat, but keeps the 3rd. Like I was saying, this would make it easier to bolt up the borla hush, right?

Hmm. .. I don't know if I'm going to need Kartboy hangers, I heard that it will just bolt up to the stock hangers and since it has the donut ring it will bolt up easily to the stock dp. Unfortunately, the helix (and many other DPs) have a flat flush flange, so you need an adapter to hook up the borla hush to the helix.

I really didn't want to spend like 400 bucks for a downpipe, but let me know what you guys think about going with the half sized dp that keeps the 3rd stock cat. Or if you guys have any other options that's cheaper than the helix dp, I'm all ears. thanks.

subabu05

+1 for uppipe. If egt gets too hot (if you use utec) the cat in the uppipe may break down and get sucked into your turbo, and then you'll find yourself as part of the population of Suckville.

Oh and get the downpipe too, it makes a huge difference powerwise. I would stay away from gutting the uppipe just from the standpoint that if any part of the cat is left in there your turbo might eat that too which would mean bad news. If you're worried about stealth, get an uppipe used from an STI either USDM or JDM. As far as brands, I love the stuff I got from Daddy's SCP. Great quality and good price too. I really need to write a review but I've been lazy. www.daddysscp.com