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Old 09-30-2013, 03:22 PM   #1
2008SUBARUWRX
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Default Catless downpipe question

Hey guys I installed a catless downpipe last night on my 2008 WRX and now I have a massive exhaust leak, and it's right where the exhaust meets the downpipe and I used a new gasket there and my factory bolts, I think the problem is that I just need two new bolts, what is your guys input?
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Old 09-30-2013, 03:25 PM   #2
whitegalant
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Are you running the stock catback? Or aftermarket?
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Old 09-30-2013, 03:57 PM   #3
2008SUBARUWRX
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Aftermarket, it's an Invidia downpipe
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Old 09-30-2013, 03:58 PM   #4
2008SUBARUWRX
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Oh catback sorry no I have a 3 inch Agency Power exhaust
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Old 09-30-2013, 05:14 PM   #5
Padrizzle
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Long as the end of the invidia catless is 3in and the catback meets up properly, a new donut gasket and proper (spring)bolts should hold it together. I had a exhaust leak in mine for the first day or 2 because the donut gasket was not sealing properly.
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Old 09-30-2013, 05:29 PM   #6
freebirdfabrications
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Quote:
Originally Posted by 2008SUBARUWRX View Post
Hey guys I installed a catless downpipe last night on my 2008 WRX and now I have a massive exhaust leak, and it's right where the exhaust meets the downpipe and I used a new gasket there and my factory bolts, I think the problem is that I just need two new bolts, what is your guys input?
As long as you have the correct gaskets and the hardware is tight, there's no reason for there to be any kind of leak. Make sure the gaskets are seated correctly and you shouldn't have an issue.....
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Old 09-30-2013, 05:45 PM   #7
2008SUBARUWRX
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Well, there was a donut gasket on the factory one and the Invidia one was just flush with the catback, I put a gasket that came with thee downpipe on there tho, and used the red gasket sealant and the factory spring bolts I'm pretty sure it's just because the factory spring bolts are to long and big now.
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Old 09-30-2013, 05:53 PM   #8
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Have someone heat either the downpipe end or the cat-back end where the two meet to tweak either just a bit to have the two flat-flanges match.
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Old 09-30-2013, 06:10 PM   #9
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The stock bolts might be too long. Your downpipe didnt come with different bolts for the catback?
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Old 09-30-2013, 07:32 PM   #10
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Got her all fixed up guys! Just put new bolts in (shorter ones then factory) no more leak!
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Old 09-30-2013, 07:34 PM   #11
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The paper gasket some of these pipes come with are prone to leak much easier than oem, or even tear apart even from the heat.
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Old 09-30-2013, 09:51 PM   #12
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It was a metal gasket I had man not that cheap **** lol
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Old 10-01-2013, 05:04 PM   #13
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I have a catless invidia DP and have the same problem. Just ****ty quality.

Actually the catless DP has caused me to get boost creep. I'm getting rid of it, I suggest you do the same.
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Old 10-01-2013, 05:44 PM   #14
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Quote:
Originally Posted by jmacman12 View Post
I have a catless invidia DP and have the same problem. Just ****ty quality.

Actually the catless DP has caused me to get boost creep. I'm getting rid of it, I suggest you do the same.
I'm not sure how you even get boost creep on a 2.5RS.
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Old 10-01-2013, 05:59 PM   #15
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Quote:
Originally Posted by Leafy View Post
I'm not sure how you even get boost creep on a 2.5RS.
My car's been swapped with an 06 WRX motor, I just don't want to call it an 06 wrx because it's not.
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Old 10-01-2013, 06:01 PM   #16
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You're not getting boost creep with a td04 either.
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Old 10-02-2013, 12:13 PM   #17
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I don't think he knows what causes boost creep or what boost creep even is. My invidia works perfectly fine.
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Old 10-02-2013, 12:44 PM   #18
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Quote:
Originally Posted by Leafy View Post
You're not getting boost creep with a td04 either.
Haaa i used to get boost creep on my '06 with TD04 all the time... so yes it can happen
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Old 10-02-2013, 12:46 PM   #19
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Quote:
Originally Posted by Longarm View Post
Haaa i used to get boost creep on my '06 with TD04 all the time... so yes it can happen
Not possible. The compressor is too small to make more than 12-14 psi at high rpms on an ej255, and if you're getting "boost creep" to a pressure higher than you wanted below 4k rpm your tune just sucks. In other words you dont know what boost creep is.
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Old 10-02-2013, 01:32 PM   #20
jmacman12
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Quote:
Originally Posted by Leafy View Post
You're not getting boost creep with a td04 either.
I don't have a td04, I have a vf43. And yes I do currently have boost creep.

Quote:
Originally Posted by k04sti View Post
I don't think he knows what causes boost creep or what boost creep even is. My invidia works perfectly fine.
You're right I have no idea what boost creep is...

Quote:
Originally Posted by wgknestrick View Post
With the countless threads about boost creep problems with turbobacks on the 2.5l STI, I think this thread should be helpful as a quick summary to those planning on moddifying their STI.

Q) What is boost creep?
A) Boost creep occurs when the wastegate is physically unable to bypass enough exhaust around the turbine on the turbo.

Q) Is boost creep harmful?
A) Yes, boost creep is one of the worst problems you can have with a turbo engine. Boost creep means that there is NO way for the boost pressure to be controlled. Boost pressures in excess of 20psi!!! have been recorded on STIs with TBE before the ECU cuts fuel.

Q) What causes boost creep?
A) Installing a turbo back exhaust whether aftermarket catted or not will in almost all cases cause boost creep to a certain extent.

Q) Are there any other options to prevent boost creep besides porting the wastegate?
A) Yes, Installation of an exhaust that either keeps the stock OEM muffler or one of the stock cats should not cause boost creep.

Q) How do I know if I have boost creep?
A) If you have a full TBE, then you probably have it. A boost gauge will tell you what pressure you are at as well. Fuel cut occurs when the ECU senses boost in excess of 17.5psi for 2-3s. Fuel cut in my experience is a very violent "stutter" from the engine that resembles extreme knock, followed by CEL.
My invidia works too, what a coincidence

It just happens to be working a little too well...
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Old 10-02-2013, 04:20 PM   #21
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Try getting some regular grade 8 nuts and bolts from the hardware store in case you're running out of threads to get it fully tight. Also, the Grimmspeed gaskets for 3" flat flange exhausts are a good deal thicker and might seal better. If either of the flanges are warped, you might need to get it reworked at a shop to get it to seal 100%. My catless Invidia DP and previous Q300 exhaust mated up and sealed 100% using a Grimmspeed gasket.
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