Cat-less vs catted downpipe (power)

[Effin Ponderous]

You will have the cat on the mid pipe.

True, but I will be running a cat free up. Will one cat be enough to keep the stink away?

[Rommel]

My car doesn't stink, the only cat that I have is in the mid pipe. No more cat in the UP.

[wukindada]

As mentioned a HFC downpipe like the COBB will be less than a 5hp diff between the catted vs non-catted;)

[j255c]

my car isn't catted and only stinks when i go in reverse w/ the windows open.

[2furious]

Interesting....

 

I got one question... If we lose any one of the cat, can we pass the emission test? I saw a thread that Subie runs clean even without cat but want to make sure. If not, what are you gonna do later when you need to take emission test?

[Rommel]

it will pass the sniffer test

[dvdt]

Small difference in absolute power between HFC and totally de-catted - and as to whether or not you'll notice the smell...well, that's totally up to your own unique biology and how sensitive your nose (as well as that of your passengers') happens to be.

 

Your choice.

 

As to the "shorty," that is an option which only deletes the second cat (first downstream of the turbo). For the third cat position, you can thus either retain the stocker, switch out to a HFC solution, or, alternatively, run a "test pipe" for a totally catless (post turbo) solution. It's "modular," for lack of better wording.

I think I'm confused? Or maybe I get it? No wait, I'm confused.

 

Is this right?...for not too smelly Cobb Stage2 you can do:

A) uppipe + "shorty w/ 3rd cat

B) uppipe + HFC downpipe

 

I'm assuming option B = slightly better performance at more cost.

[rc0032]

Is this right?...for not too smelly Cobb Stage2 you can do:

A) uppipe + "shorty w/ 3rd cat

B) uppipe + HFC downpipe

 

I'm assuming option B = slightly better performance at more cost.

Thats about right. There are a few more considerations, like you are introducing 1 more area for a leak. What are your final goals for the car? If its stage 2; get the short you won’t notice the difference, if its anything more get the full DP.

 

Right brother TSi+WRX?

[TSiWRX]

^ Exactly, brother rclark0032 <-- way too long to type, even if you think thatmy handle is too long to type!

 

 

At the same time, though, one should balance-out the potential for a leak with the "modularity" of such a two-part system, which can be both a performance as well as maintenance plus.

 

It's always a compromise, ain't it?

 

-------

 

True, but I will be running a cat free up. Will one cat be enough to keep the stink away?

^ Like brother WRX_LGT said, most of us don't see any cat(less)-odor if we keep either the stock 3rd cat or use a quality aftermarket HFC solution at that position.

 

My super-sensitive-nosed wifey, she can detect a bit of odor when the vehicle is completely cold-started and if we subsequently sit in one place for too long (i.e. winds carrying that odor in-vehicle), but she says it's only slightly worse than in her completely stock '05 WRX, comparatively. I have the stock 3rd cat in-place on my LGT - it's my only feline.

 

But like I said, this is a somewhat personally-variable issue - for people with sensitive noses and who strongly dislike this odor, like my wifey, they'll probably detect at least a small whiff, occasionally...and slightly more with a HFC setup, especially on cold-starts.

 

However, for others, like myself, I could honestly run a fully catless LGT and probably not notice the difference at all, based on how far away the tail-pipe is to my nose, on this car, as opposed to my DSMs.

 

Besides, I like the smell. I'm only being nice to my wifey, who's had to bear with some 10+ years of my various catless DSMs.

[Effin Ponderous]

Sold...half cat it is...where is it? Is it here yet?

[wukindada]

COBB is showing a tentative release date of July 2008....I am sure it will be released earlier though;)

[SpeedNeeder]

Cat delete = fuel smell?

I just want to clarify, anyone can smell the clutch if they slip it just a little.

[TSiWRX]

Cat delete = fuel smell?

 

^ Sorta "fuel," but distinct, at least to my nose.

 

When I'm following a catless vehicle, I can always tell.

 

I just want to clarify, anyone can smell the clutch if they slip it just a little.

 

At least on a number of the '05s, this seems to be quite a variable issue. Some get "clutch stink" very, very easily - search for those terms, you'll see where this complaint comes in. Others don't see this problem at all.

 

I'll only get a whiff of clutch smell (and to-clarify, this is much, much less severe than the noted "clutch stink") if I do a 5K+ RMP clutch-slip launch.

[yellowdogLGT]

I'll only get a whiff of clutch smell (and to-clarify, this is much, much less severe than the noted "clutch stink") if I do a 5K+ RMP clutch-slip launch.

 

Speaking of, do you launch our LGT's like we launched our TSi's? This is assuming stock clutch. Damn. Which leads to the next question - when to change out the clutch... I started slipping at about 260 HP on the DSM... I presume the LGT is a little more heavy duty.

 

Thanks

[bradlgt21]

I heard at stage II it holds but some people have had problems at that point. So I guess stage II is the limit. It matters how hard you launch it as well. never launch the car and you will be fine launch every day and it will run out faster.

[TSiWRX]

To reply to the two posts above:

 

I do about 2 3K-RPM "slipped" launches per week - typical "Stage II" power levels. Keep in mind, though, that I never do two launches back-to-back.....

 

As for a "power" reference - my last dyno was right around the 215 mark on both sides (stock STis and EvoMRs, on this dyno, barely punch over 200, both wHP and wTQ - to give you a reference). Since then, by road-dyno, it seems that I've gained an additional 15 to 20 wHP/wTQ due to new hardware upgrades (keep in mind that this is un-tuned, "raw"). Unfortunatley, I have no way of quantifying this against my TSi, as she puts down a modest 273 wHP or so, but has always had an ACT 2600 paired with it.

 

Back to the LGT - so far, I've been lucky.

 

I did a 5.5K slip-launch this AM, though, and the smell is staying with me. I'm gonna run her on the highway a bit this PM to see if I'm gonna need to shop for a new clutch! Doh!

 

 

Speaking of, do you launch our LGT's like we launched our TSi's? This is assuming stock clutch.

 

Yes, my basic technique is the same. I never had the stock clutch on my DSMs for long, though - not that I destroyed them or anything, but rather, I just always upgraded them.

 

To-note, I'm not a drag-racer, so you'll want input from brothers like John M and johnAWD to contribute on this. I'm just an average "fun" daily-driver, and my vehicles, including DSMs, have never been more than such.

[yellowdogLGT]

Thanks,

 

I'm probably going to go as far as a low 13-sec car, so a clutch swap will be in the works anyhow. Hopefully new axles will not be. I had my Talon up to 230 whp and I snapped my rear left three-bolt, so I'm a little gun shy with the brittle parts.

 

You ever work with Buschur on your Subaru? He was my "go to" guy for parts and info, and if he's dabbling with Subie's I'd like to stick with him.

[TSiWRX]

^ I'm not completely certain on Dave's stance in trying to again market Scooby parts. From what I understand, he stopped doing so in the past as he just couldn't generate the following (and hence, cash-flow), to support such ventures.

 

My local club, LERSOC, has a really good relationship with Dave - and routinely hosts tune days using his heartbreaker of a Mustang.

 

He's a great guy (very down-to-earth,and we chatted for about an hour on my then-to-come daughter and his little girl, while my car was on the dyno getting tuned), and honestly, if he started doing Scooby stuff, I know that he'll definitely have our local support, myself included.

[triniexr]

I heard that there are 3 cats in our cars, if i remove the one in the up pipe and one in the dp, do you think I can still pass an emissions test?

[TSiWRX]

^ Not certain if any LGT owners have had to get their vehicles "sniffed," yet, but it's well-known that modern turbo Scoobys can easily pass the sniffer test with even just that third, and last, cat in-place, provided that you're decently tuned.

 

Note, though, that whether or not you'll pass a visual inspection will depend on the knowledge and thoroughness of the technician.

 

Similarly, whether or not you'll pass the OBD-II scan will depend on whether or not you've properly installed countermeasure-equipped aftermarket engine-management or other bypass devices.

[Irrational Exuberance]

Interesting....

 

I got one question... If we lose any one of the cat, can we pass the emission test? I saw a thread that Subie runs clean even without cat but want to make sure. If not, what are you gonna do later when you need to take emission test?

 

just keep you stock shit for that... takes 10 minutes to put the downpipe in

[SubiGT]

I think I'm leaning toward the more expensive, HFC full DP. Who has the best one out there for the MT? I know I'll be happy with Cobb, but she's a pricey piece of metal.

[Legasee]

I think I'm leaning toward the more expensive, HFC full DP. Who has the best one out there for the MT? I know I'll be happy with Cobb, but she's a pricey piece of metal.

 

Invidia just came out with their downpipe for the manual tranny....TDC's got them at "pre-sale" price....it's in the vendor's market place section

[BOXRPWR]

You can make good power and keep a HFC. I've got a PDE catted DP.

[JDM-STI]

You can make good power and keep a HFC. I've got a PDE catted DP.

This is soooooo true. I've made close to 500 whp on my STI with a Helix catted DP (487 with fuel trim issues). Only reason we haven't made it yet is due to some closed loop fuel trims that we are fighting right now.I made 460/460 (safely) at the wheels at only 25lbs of boost with my FP Red/Meth set up. My car will make about 31lbs of boost holding 30 to redline on an IWG. So I'm sure 500 wheel will be attainable. I said all of this for this reason, YOU CAN MAKE BIG POWER WITH CATTED DP's. Most other guys with catless DP's with almost identicle mods on the same dyno an same tuner are only making 3-7 more HP than me. GOing catless isn't worth that small of a gain IMO.

I have a PDE catted DP on the Leggy.