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Old 04-27-2005, 06:26 PM   #1
AdmiralWRX
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Default Should I be replacing my UP when I go to Cobb stage 2?

I know that Cobb stg 2 only recommends a downpipe, but is it a good idea to replace the UP as well? I've seen posts implying that going to stg 2 (I have a full 3" TBE on it's way) puts undue stress on the stock catted UP.

Is there any truth to this? At this point since I'm already dropping $$ on the TBE I'm thinking that I should do the UP while I'm at it. The only issue is the time required to replace the UP, which is considerable.
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Last edited by AdmiralWRX; 04-27-2005 at 06:33 PM.
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Old 04-27-2005, 07:19 PM   #2
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I wouldn't worry about it. If you have the cash and time, you might as well replace the uppipe since the downpipe will have to be off to get to some of the fasteners, otherwise let it go and be happy. I didn't really notice a butt dyno increase in peak power, I did feel that boost came on quicker during shifts. This alone makes the car feel a bit quicker. Looking through some delta dash logs of my car and a friend's car we didn't really see that much of a difference in spool time (hmmmm), who knows though. It's up to you. If you think you'll do it in the future get it out of the way now so you don't need to rip the car apart twice.
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Old 04-27-2005, 08:08 PM   #3
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If I'm going to mod UpPipe, what other parts will need to be taken off during installation? I want to pay just one installation charge while having most stuffs put in at the same time..
IC Y-pipe? Downpipe? Even the turbo itself? (I'm also considering P&P Monster TD04 if I can get a ready-to-go unit from Deadbolt, then after installation, I can mail my stock TD04 back for some deposits back.)
I'm not considering headers tho...
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Old 04-27-2005, 10:36 PM   #4
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Replacing the up pipe is the first performance mod you should do. Having your car run hotter and cooking that preturbo cat even more will not be good at all. Doing a up pipe with be alot cheaper then going a turbo and up pipe!!

If you dont beleive me read the up pipe FAQ or ask in the 2.0L turbo forum, just puit on your flame suit first.
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Old 04-27-2005, 11:42 PM   #5
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<---Cobb stage 2 and no UP pipe...never had a problem. SN 125. For the Cobb Stage 2 all you need is a good bellmouth downpipe.

For the 4eaters, yes do the up pipe. It will spool a little faster. Less lag...
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Old 04-27-2005, 11:53 PM   #6
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Getting the catted uppipe out is a good idea. It will yield you quicker spool and peace of mind.


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Old 04-28-2005, 11:02 AM   #7
AdmiralWRX
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Thanks for the input, guys. Although there seems to be two opinions: leave it in and don't worry, or take it out now it's risky.

Anyone have issues with leaving the catted UP in there? I'm down with the "peace of mind" concept, I'll probably replace it just for that, but I'm just curious...
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Old 04-28-2005, 11:36 AM   #8
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I've had problems in the past by leaving the uppipe installed with a downpipe and BOV.





Moral: Remove the stock uppipe no matter what Cobb says.
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Old 04-28-2005, 12:25 PM   #9
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^^^just curious. how many miles on that with the bov? did the turbo get damaged?
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Old 04-28-2005, 12:41 PM   #10
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Quote:
Originally Posted by fasterthanrayswrx
^^^just curious. how many miles on that with the bov? did the turbo get damaged?
~ 3 months so about 7,000 miles give or take. That was a long time ago so I can't remember for sure. The turbo was fine. When the precat dislodged it hit the EGT sensor (which you can see in the photo) and threw my car into limp mode.
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Old 04-28-2005, 01:56 PM   #11
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I gutted my stock unit. Free but I must admit it's not as easy as you think... that damn thing was a PITA... not difficult just time consuming if you don't have the right tools. Still worth it in the end though.
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Old 04-28-2005, 03:59 PM   #12
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Increasing boost pressure and heat in the exhaust can severly decrease the life of the preturbo cat. I don't know what cobb was thinking about when they only required a DP for their stage 2 setup.

However, since they released their own uppipe, they have included it as a "strong suggestion" on the map details page...go figure
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Old 04-28-2005, 05:32 PM   #13
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I have had it still in there for 2 years with no problem. I am looking to get it out of there but it has been fine. I'm looking for the quicker spool more than worried about the pre turbo cat coming apart. I am Cobb stage 2
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Old 04-28-2005, 06:00 PM   #14
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Would a high flow UP be any better? In the future, I don't want to worry about CEL's and I want multiple (2) cats.

I've only heard stories, but I've never heard of anyone directly that lost thier turbo to a catted UP.
I'm just figuring that at only stage 2 the high flow would suffice.
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Old 04-28-2005, 07:03 PM   #15
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Why would you spend the extra money on a highflow uppipe? The only reason the uppipe cat is there is to help with cold startup emissions...
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Old 04-28-2005, 08:54 PM   #16
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I think when most people switch to a high flow cat they usually with one in the downpipe... and I don't think most people usually put two in the system. To be honest, I haven't heard much about a hi-flow uppipe.

If you use Cobb management then you don't have to worry about CEL's. If your concerned about emissions and increasing power I think one hi-flow cat will be sufficient.
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Old 04-28-2005, 09:51 PM   #17
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Quote:
Originally Posted by mbiker97
~ 3 months so about 7,000 miles give or take. That was a long time ago so I can't remember for sure. The turbo was fine. When the precat dislodged it hit the EGT sensor (which you can see in the photo) and threw my car into limp mode.
I'd bet this more more of a function of the BOV than anything else. The constant excess fuel being dumped on it probably cause excessive heat cycling.

I know of someone else who was running a BOV and had his cat dislodge.


Mike
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Old 04-28-2005, 10:53 PM   #18
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Well, I acquired an STi uppipe (no cat) and plan on going ahead with the install when I do my Cobb DP. To me, for around 100 bucks, it's pretty obvious to try and do it, since it should help spool-up and maybe even give a few extra HP.
I wrestled with the decision for several weeks, though, so don't blame anyone who's just looking for Stage 2 Cobb to forego the damn hassle...
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Old 04-29-2005, 06:50 PM   #19
Paulie V
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Quote:
Originally Posted by crazymikie
I'd bet this more more of a function of the BOV than anything else. The constant excess fuel being dumped on it probably cause excessive heat cycling.

I know of someone else who was running a BOV and had his cat dislodge.


Mike
Yup- from the reading I've done, an aftermarket BOV seems to be the common denominator with melted/dislodged uppipes. Has anyone heard of this happening with the stock BOV?
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