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Discussion Starter #1
Tried a search and didn't find anything specifically on this issue....

Stage 2 tune/boost levels depend on the lower backpressure produced by a turbo back CATTED exhaust (as described in the requirements by Cobb). Many aftermarket turbobacks are 3" all the way. With the SPT having a 2.5" midpipe, does this still perform properly with the Cobb AP Stage 2 maps???

If it is still too restrictive, does a catless DP work best with the SPT? (considering if it will net the same backpressure as a catted, 3")


Hoping to avoid having to fabricate a new midpipe....
 

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2.5'' should be fine. your car will exhale w/o worries. 2.5 is large for any 4 banger. i am sure there are people who will dis me on this but if you had 3'' front to back you may pick up 2 or 3 more hp than w/ the 2.5 mid section. my .02
I dont see why ppl will dis you b/c you really dont gain too much more w/ a full 3". A 3" would be nice if the person is searching for more power past stage 2 though. And Cobb stage 2 only requires an aftermarket downpipe I thought, full turboback isnt required.
 

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should be fine unless you are going for some crazy numbers.
 

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Discussion Starter #6
Sweeet. Glad it will work out. Right now, still playing with the Perrin Stage 1 on the AP...pulls much smoother but I am still looking forward to stage 2. Just having a hard time finding a catted DP that won't break the bank. Hopefully I will come across a used Cobb or Perrin soon!
 
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