stewdogg Posted July 6, 2018 Share Posted July 6, 2018 I know that the closer to the heat that a catalytic converter is the better it works. What would the power benefit be of moving the cat further from the heat source? What kind of impact would it have on the turbo, if the cat was further from the turbo? Would it be a negligible difference moving it and is the stock placement the best placement for the cat efficiency vs power balance? Link to comment Share on other sites More sharing options...
relative4 Posted July 6, 2018 Share Posted July 6, 2018 High-performance DPs move the cat farther downstream from the turbo to improve flow, thus decreasing spool time and increasing potential boost. Putting the cat farther upstream improves emissions, but my Cobb DP with the cat way downstream passes Denver roadside emissions testing. Link to comment Share on other sites More sharing options...
m sprank Posted July 9, 2018 Share Posted July 9, 2018 Global Time Attack rules specify that the cat must be within 18" of the original OEM placement. So, you measure 18" from the OEM downstream cat location and install. At this point the cat is basically a spark arrestor. Within the regulations, but minimal restriction in flow as the cat will stay as "cold" as possible. You gain maybe 2whp-5whp depending on the set up. But if the extra 2 ponies is the difference between the podium and going home empty handed... Link to comment Share on other sites More sharing options...
Sarang Posted July 10, 2018 Share Posted July 10, 2018 Well if that's the marginal difference I wouldn't worry about it Link to comment Share on other sites More sharing options...
stewdogg Posted July 10, 2018 Author Share Posted July 10, 2018 Thanks for the information everyone! Someone mentioned boost creep to me today too. From the research I have done, I found that the 5th gen turbo has a small wastegate dump and moving the cat could possibly make the boost creep issue worse...? I appreciate the suggestion Sarang, I always enjoy learning! Link to comment Share on other sites More sharing options...
m sprank Posted July 10, 2018 Share Posted July 10, 2018 Creep is increased no matter what down pipe is used. The Cobb down pipes have the least amount of creep as they neck down to 2.5" right at the CBE connection. Link to comment Share on other sites More sharing options...
Sarang Posted July 10, 2018 Share Posted July 10, 2018 Confirmed. I had boost creep issues with my catted Nameless DP that was advertised to eliminate creep. I ported my waste gate to solve the issue. Link to comment Share on other sites More sharing options...
stewdogg Posted July 11, 2018 Author Share Posted July 11, 2018 Confirmed. I had boost creep issues with my catted Nameless DP that was advertised to eliminate creep. I ported my waste gate to solve the issue. Is the ported wastegate the only solution to boost creep in the 5th gen? How difficult was that? Did yo do it yourself? When did your boost creep happen? It must be the dry air there? I did read a bit of the thread on the loaner turbo... I will have to go back and read about that a bit more in depth. Link to comment Share on other sites More sharing options...
Sarang Posted July 11, 2018 Share Posted July 11, 2018 A custom external waste gate setup would be another solution, but that would be pricey. I did do it myself, it was fairly easy. I bought a die grinder and some ceramic bits from Harbor Freight and went very slowly. I had researched it extensively and read through the threads on here so I felt like I knew what the end result should look like. It took me around an hour. It is typically very dry here, but my boost creep manifested itself on cold days. On the rare occasion that I was driving in temps below ~50 F it would over boost to ~20-22 PSI. If I was (out of town) driving closer to freezing it would shoot up above 24.7 PSI even at part throttle. Basically I felt like I had to drive the car carefully in cold weather which was a drag. My understanding is that catted down pipes usually do not have over boost, but catless do. My Nameless has the worst of both worlds. Link to comment Share on other sites More sharing options...
m sprank Posted July 11, 2018 Share Posted July 11, 2018 EWG will take care of the creep. Otherwise you need back pressure or a larger wastegate opening. Link to comment Share on other sites More sharing options...
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