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BooSTIng
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Discussion Starter · #1 ·
So I am going to Stage 2 with my STi within the next few weeks. I am getting the Invidia Q300 catback, and the PTP lava turbo blanket. That much I know. However, when deciding on a downpipe I have been quite indecisive. I have always liked grimmspeeds products. And I have done some research on their limited downpipe. I was entirely set on buying and running this downpipe until I spoke to Cobb yesterday.

According to cobb, this downpipe may, or may not work with the cobb ots stage 2 map. Their reasoning is that their downpipe is a bellmouth instead of a divorced wastegate, and their map is made for a bellmouth design. And, the cell count of the cat on the cobb is 300, where the gs one is a 200 cell cat. This could cause changed in back pressure and cause issues with the ots map.

So, is anyone running the gs catted downpipe on their car with the ots stage 2 map? If so, any issues to speak of? I just want to be sure that I can run this without issue until I get the rest of the parts I want before my protune.
 

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Master Baiter
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12,649 Posts
SMH

I can convince a girl to choose her wedding dress easier than it is to talk you into choosing a stupid downpipe...
 

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19 Posts
If your mapper has advised a bellmouth then what decision is to be made.

Have this one that will cause problems or this one that won't be an issue.........

Sent from my HTC One M9 using Tapatalk
 

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BooSTIng
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2,253 Posts
Discussion Starter · #5 ·
I had an invidia divorced wg dp on my last wrx and ran it on the cobb ots map with no problems for a while before I bought more parts and got protuned
 

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following this. I assume a q300 cat back with stock DP is fine to run with the AP on a stage 1. Thats kinda what i was worried about was not going all COBB.
 

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You would be correct, a catback doesn't require a tune at all, its basically just a sound maker. For the stage 1 AP tune you need no other parts, however you can run it with intakes that are specified in the AP OTS maps, just make sure your intake matches the ones supported in the tune and you're golden.
 
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