You Downpipe Opinion
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Your Downpipe Opinion
Currently I have a Borla Hush cat back and want to install a downpipe for a Cobb Stage 2 (when my AccessPORT arrives!!!). My debate starts with the cat. I was thinking of eliminating it as the Helix DP does but do not want it to be too loud and the odor of no cats. Bosal's DP does not eliminate the 3rd cat but still have the restriction of the 3rd cat.
My objective for my WRX is approx 300HP (Crank) and keep it as much as a daily driver as possible. In the near future, I will be installing a helix flex uppipe but want to work on the post turbo exhaust first.
Will I not gain as much HP by keeping the 3rd cat instead of eliminating it? How well do the high flow cats work? Is it worth buying a downpipe with the high flow cat (Cobb's DP) or does an aftermarket company manufacture just a 3rd cat section?
My objective for my WRX is approx 300HP (Crank) and keep it as much as a daily driver as possible. In the near future, I will be installing a helix flex uppipe but want to work on the post turbo exhaust first.
Will I not gain as much HP by keeping the 3rd cat instead of eliminating it? How well do the high flow cats work? Is it worth buying a downpipe with the high flow cat (Cobb's DP) or does an aftermarket company manufacture just a 3rd cat section?
Last edited by mastros2; Mar 21, 2004 at 05:47 PM.
Originally posted by vteg
The downpipe cat is a bigger restriction than the third cat. I am sure you can get 300chp with the stock third cat.
Stromung sells a 3 inch cat pipe.
The downpipe cat is a bigger restriction than the third cat. I am sure you can get 300chp with the stock third cat.
Stromung sells a 3 inch cat pipe.
I dont think you can go stage 2 with the factory 3rd cat, you will probable need a high flow cat.
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Joined: Aug 2003
Posts: 37
From: 02474
Car Info: WRX Shooting Brake
I have a Bosal DP and a Borla Hush, with 250 wheel hp. I'm going to replace the factory cat with a Stromung high-flow cat in a few months. I think it may get me 5-10hp or so. Mine is a daily driver as well, and it isn't way too loud. The Cobb and PDE high-flow cat downpipes are way outta my league right now.
Last edited by McBain; Mar 21, 2004 at 03:51 AM.
Originally posted by vteg
To go cobb stage 2 you only need to get rid of the cat in the stock downpipe.
To go cobb stage 2 you only need to get rid of the cat in the stock downpipe.
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What recommendations do you have for the midpipe with a high flow cat. I might purchase a bosal dp and keep the oem midpipe for the time being. Over the summer I would like to swap it out. I am wondering if I should just wait until I have the funds for a whole DP with a high flow cat which replaces the mid pipe as well.
Any opinions??
Any opinions??
Registered User
Joined: Apr 2003
Posts: 66
If your just looking to go cheap for now, pick up either a Bosal or Stromung downpipe, then later, if you decided to add a larger turbo, pick up a 3" mid pipe with a high flow cat. Stromung would be the obvious choice, since it will mate up to the dp and your Borla hush.
Rally Performance's STi Hunter uses the stock 3rd cat with Scooby Sport dp, cat back and ECU reflash and puts down nearly identical numbers as Cobb's stage 2, so I think you can get away with the stock pipe for now.
Rally Performance's STi Hunter uses the stock 3rd cat with Scooby Sport dp, cat back and ECU reflash and puts down nearly identical numbers as Cobb's stage 2, so I think you can get away with the stock pipe for now.
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Originally posted by mastros2
What recommendations do you have for the midpipe with a high flow cat. I might purchase a bosal dp and keep the oem midpipe for the time being. Over the summer I would like to swap it out. I am wondering if I should just wait until I have the funds for a whole DP with a high flow cat which replaces the mid pipe as well.
Any opinions??
What recommendations do you have for the midpipe with a high flow cat. I might purchase a bosal dp and keep the oem midpipe for the time being. Over the summer I would like to swap it out. I am wondering if I should just wait until I have the funds for a whole DP with a high flow cat which replaces the mid pipe as well.
Any opinions??
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Joined: Feb 2003
Posts: 488
From: 12.9 / 105+
Car Info: black my03 5mt wrx s/w
Originally posted by Georgethefierce
This is pretty much my set-up...........gutted stock up-pipe, Bosal Downpipe, stock mid-pipe (w/ 3rd cat intact) and Bosal twin tip cat-back................It'll keep you happy for a little while!
This is pretty much my set-up...........gutted stock up-pipe, Bosal Downpipe, stock mid-pipe (w/ 3rd cat intact) and Bosal twin tip cat-back................It'll keep you happy for a little while!
that's what i did. it resulted in even more grinning!
jm2c
ken
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just got my GODSPEED downpipe today (SWEET) and i have a 3rd cat with the guts removed. the COBB stage II reflash next week and then a run to the dyno.....i'll let you know what it runs with the 3rd cat there........i'm gonna dyno it boths ways. COBB says keeping the 3rd cat intact will cost about 10 HP in stage II trim. about 275 at the crank. 285 at the crank without the 3rd cat.
later, riggs
later, riggs