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Discussion Starter · #1 ·
Hey all. Looking for some help here. I have the newer style Cobb GESI dp on my car. I had the Nameless catback on it but decided to switch to the Cobb catback. My problem is after mounting per instructions on the Cobb website there is a significant gap where the flanges mate. What is happening is the stepped shoulder bolts that have the springs on them stop on the middle flange that Cobb provided. Those holes aren’t big enough to allow the stepped spring bolt to tighten any further. I hope this is a clear explanation of what’s happening.
Can anyone offer some help before I reach out to Cobb?
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If you have an aftermarket 3" exhaust, I dont think you need to use an adapter to mate it to the 3" downpipe. I would try ditching the adapter and spring bolts. Try using just the gasket, and also regular nuts and bolts. It should line up and bolt right up.
 

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Discussion Starter · #4 ·
Unless I read the Cobb directions wrong, they say to use that adapter for both the stock catback and their catback. I have an email into Cobb so I hope to have an answer soon.

that adaptor is only used for stock exuahst or aftermarket exhaust that tapers down to 2.5"at the flange to the downpipe.
 

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I've just put mine on, COBB TBE with gesi cat. Similar gap. Reading through the directions afterwards, I believe you use the flat gasket, adapter, then oem doughnut gasket. Mine broke apart, so I've got a new one coming. 524210, 524220 - Subaru GESi Downpipe - Customer Support Center - Confluence

If using The COBB 3" catback or stock exhaust you'll take the rear donut gasket off of the factory downpipe and add it on to the provided adapter then insert the expanding end into the downpipe with the supplied 3" gasket. If using a different aftermarket 3" exhaust, you'll use just the provided hardware and supplied 3" MLS gasket.
Why couldn't they design it so the adapter wasn't needed on the complete TBE. Seems silly.
 

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Discussion Starter · #9 ·
Sorry for the delay in getting back to this. So after numerous emails with Cobb, my setup was correct. After a new crush washer (provided by Cobb) and new oem donut gasket the system sealed up nicely. There is still that weird gap where the shoulder bolts bottom out on the plate but I felt no air leaks after the new gaskets were installed.
 
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