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Cat-less vs catted downpipe (power)


Legasee

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I'm torn between getting a catted or a non-catted dp (got the AccessPort coming in a few days). I've only had experience with a catless Invidia dp on a WRX, and never had the chance to ride in a catted dp car.

 

I was wondering what/if there is a "significant" difference in the performance (power) between a cat-less vs catted downpipe? thanks and any info would be great.

 

I'm in Cali so we're screwed going either way...but if there's gonna be a difference in power (either way, the exhaust is gonna smell bad anyways :lol: ), I'll probably go catless for power and less $....

 

Any info would be great! :)

In Taiwan now...:spin:
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:lol:

cool...cool...

 

sux with the limited selection of dp's out there for the 5EAT..but ya...I guess I might as well get "a little" more power and save some $$$ and go catless...so ya... my car's gonna stink soon...very soon :icon_bigg

 

..."dude, your car stinks!!:lol: "...":orly: ,do you mean 'literally??'"...ok...i'd better calm down now :lol:

In Taiwan now...:spin:
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I'm most likely going for MR header with intergrated up pipe(cat delete), and trying to decide on a catted or catless dp now...just read up on COBB's description of their catted dp...I might go with catted if I can get a good deal on it :D
In Taiwan now...:spin:
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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 love Winky, my "periwinkle" (ABP) LGT! - Allen / Usual Suspect "DumboRAT" / One of the Three Stooges

'16 Outback, '16 WRX, 7th Subaru Family

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or you can do what i did -- keep the cat in the uppipe, but loose both the cat's in the DP -- No smell at all, except while idling in the driveway or similar... even the wife hasnt noticed it.

 

Hate to sound like a spoilsport, but the uppipe cat is THE one cat that you want to lose. By taking the UP cat out you can increase spool and delete a known potential problem area: cat parts in the turbo!

 

Over the years, there have been quite a few documented WRX uppipe cats that have been ingested by their turbo.

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Hate to sound like a spoilsport, but the uppipe cat is THE one cat that you want to lose. By taking the UP cat out you can increase spool and delete a known potential problem area: cat parts in the turbo!

 

Over the years, there have been quite a few documented WRX uppipe cats that have been ingested by their turbo.

 

 

yes... and no....

 

THe 2 feet after the turbo are the most important in producing power - but yes - the cat before the turbo will descrease spool time..

 

 

I've been logging temps and keeping an eye on things and so far have no cause for concern that my uppipe is in danger of falling apart... however whenever I have some spare time I do plan on swapping out to a catless UP.

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^^...I'm getting the MR header (integrated flex up) if it'll go ok/good with AP stage 2 (is there a stage 2.5 or something :D?).

 

Is there an AP map specific for aftermarket header (deleting up cat)?

 

Are you talking about up cat delete but keeping OEM turboback?

 

If so, check out PDXTuning's packages. They number their stages differently than everyone else. However, in their stage sequencing, they delete the cat in the uppipe first before messing with the turboback.

 

Check out PDX stage 1 (uppipe cat delete).

 

http://legacygt.com/forums/turbo-powertrains-2-0gt/8241-pdxtuning-results-legacy-stage.html?highlight=pdxtuning+dyno

 

BTW, let us know how the MR header works out for you.

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yes... and no....

 

THe 2 feet after the turbo are the most important in producing power - but yes - the cat before the turbo will descrease spool time..

 

 

I've been logging temps and keeping an eye on things and so far have no cause for concern that my uppipe is in danger of falling apart... however whenever I have some spare time I do plan on swapping out to a catless UP.

 

Keep watching! The increased flow capability caused by reduced restriction in the DP and beyond helps to speedup the UP cat's demise. We have seen UP cats in various stages of damage, from the loose cat to the burned off/totally disintegrated EGT probe (gone thru the turbo?). Notice the STi has no UP cat to begin with?

 

-SRX

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