Gutted stock downpipe?

[BAC5.2]

Is gutting the stock downpipe good enough for a Cobb stage 2 OTS map? I have heard conflicting info. Some say yes, some no.

 

Input?

[GTTuner]

That is fine, you can leave the third cat alone. Just data log and make sure your safe. My 1st stage 2 set up had a gutted DP. I went to the Invidia catless pipe after my 18g and noticed a bit better spool.

[clarkwgriswold]

Gutted stock dp is OK for stage 2. That's what I'm running now. I recomend leaving the third cat. I took mine out and the smell is mor noticeable.

[GTTuner]

Gutted stock dp is OK for stage 2. That's what I'm running now. I recomend leaving the third cat. I took mine out and the smell is mor noticeable.

 

 

Plug up the exhausters in the rear quarter panels and you will eliminate the smell getting into the car while you are driving.

[TSiWRX]

By collective experience of the BL/BP community (since late 2004, for some who are still here), yes, it should be fine.

 

Like GTTuner advises, though, I'd definitely datalog it, to make sure that your car, BAC, isn't one of the ones which just happens to lie on the outskirts of safety...it's been shown repeatedly here that the Cobb OTS maps aren't necessarily completely and totally "safe," and that this varies highly, depending not only on the modifications undertaken, but simply between unique, individual, end-vehicles.

 

Referring back to this post on SubaruForester.org (to which you'd contributed, BAC, back in May):

 

http://www.subaruforester.org/vbulletin/f95/accessport-stage-2-update-74433/

 

What we know, as a community, is that the post-turbo cats are the biggest problems in the "Stage II" equation - and that, speaking of a stock/OEM setup, it's that first post-turbo cat that's gotta go. Gutting it will work, but remember, there's a big blank plate that's going to also impact flow.

 

Previously (c. 2005), Cobb had said that the TBE (or, alternatively, the elimination of cats.) served only to optimize power, but their "by-Hoyle" advice has definitely gotten more and more conservative over the years, as-evident via the written cautionary statements/"requirements" on their Map Notes and other such.

 

The "conflicting info." comes into play, truly, only in that their technicians, on an INDIVIDUAL basis, have presented the community with information which does not match that of what's stated as "by-Hoyle."

 

In terms of the community of hobbyists/enthusiasts, though, gutting of the factory pipework has always been an accepted/acceptable means of accomplishing "Stage" goals.

 

 

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BAC - In the referenced SubaruForester.org thread, you'd mentioned your view that the apparent hardware change, i.e. of using an aftermarket DP, would cause the dealership to take unfavorable action, when it comes to potential powertrain warranty claims.

 

I reminded you, there, that that's more a concern if the ECU is tampered with.

 

Remember, since your ECU has already been reflashed via AccessPORT, if you show up with a warranty claim, even with what *appears* to be a factory DP on the exterior, the miscue on SSM-III uplink will already cause the car to undergo extra scrutiny - at that point, having or not having an apparently non-OEM DP may well be a moot point, and certainly, if a more enterprising/knowledgeable technician were to find a gutted DP, that would only further complicate the scenario.

 

Truthfully, unless you were doing this to foil the efforts of your local emissions-inspection techs, I honestly would just go with a proven-quality aftermarket DP, and call it a day.

 

Again, as before, and as with other enthusiast here in our community, I'm not saying that anyone - you or otherwise - would do something like this, in an effort to defraud Subaru of warranty coverage on an obviously modified vehicle. And that's the honest truth.

 

Rather, I'm just saying that I really don't see the point of doing so: of maintaining stock appearance in an area where, for a "sleeper," would virtually never be seen, if not specifically for the need to foil the usually clueless, careless, and ignorant state/municipal emissions examination technicians.

 

And if cost is an issue, I'd say that purchasing a second-hand aftermarket DP of good quality, and making sure that the seller is a reputable one (thus hopefully avoiding the potential of warped flanges, corrosion, etc.), would be more cost-effective than gutting the stocker.

[Deaks2]

Plug up the exhausters in the rear quarter panels and you will eliminate the smell getting into the car while you are driving.

Explain this to me

[BAC5.2]

Behind the rear quarter panel trim (or behind the trunk liner in your car), there are one-way vents that are equalization vents. They prevent the car from being a sealed drum, and keeps the pressure equalized between the inside and outside. They do, however, allow smells (and water, if you decide to ford that high) into the cabin. Plug them up, no more smell inside the car. I'm sure there are some ill effects, but I can't think of any significant.

[BAC5.2]

TSi - I think you mistake my intentions. I'm merely curious, and I like to expand my knowledge base when possible. I saw someone selling a stock downpipe and suggested gutting it for a "poor mans stage 2" and wanted to know what the community thought about going stage 2 with that setup. When I decide to do exhaust work, I'm getting something with a cat. Probably a custom TurboXS downpipe.

[TSiWRX]

^ Ah, gotcha, NP. I was mainly concerned about emissions testing, the visuals: in not knowing how well-trained your locals are - there was one member here who well-publicized the fact that he'd welded on some of the factory cats.' heat-shields to an aftermarket, completely catless DP, to defeat CA visuals.

 

Truthfully, the "confusion" on this issue, in so far as I see it, comes from the disconnect between what Cobb's official recommendations are, "by-Hoyle," and what their techs have said to individual hobbyists in-private, over the phone, via IM, or via PMs.

 

Historically, we've always been told that a "gutted DP," specifically of the very first post-turbo cat., is all that was actually truly "needed" to run Cobb's "Stage II" maps, "safely."