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991.2 Cat Bypass owners

Old 02-14-2018, 06:06 PM
  #16  
Fabspeed Motorsport
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Hello All,
My name is Phil and I am reaching out from Fabspeed.
This is a very sticky topic for owners everywhere. There are huge upsides to both and downsides to both.
Pro's
Sport Cat's:
1. No check engine light
2. Low fuel smell
3. great sound
4. 93% Free flow when using HJS High flow catalytic converters
Con's
1.Price much more expensive of Cat bypass
2. Leaves some power on the table

Cat bypass
Pro's
1. Raw sound
2 100% free flow
3. The most power you will be able to get out of the part
Con's
1. Smell
2. Check engine light
3. Issues with emissions in some states

If it is not a track only car we highly suggest going with the sport cats. It is less of a headache for emissions, CEL, and smell. Also if you are going with cat bypass normally you will go with a performance muffler or no muffler. If it is a track only car to get the real benefits of the Cat bypass you should go with the full exhaust and you might end up with going over DB ratings at some tracks. We do make some turn down tips to help out with sound but now you are fighting sound as well.

I hope this helps
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Old 02-14-2018, 06:15 PM
  #17  
R_Rated
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Originally Posted by Fabspeed Motorsport View Post
Hello All,
My name is Phil and I am reaching out from Fabspeed.
This is a very sticky topic for owners everywhere. There are huge upsides to both and downsides to both.
Pro's
Sport Cat's:
1. No check engine light
2. Low fuel smell
3. great sound
4. 93% Free flow when using HJS High flow catalytic converters
Con's
1.Price much more expensive of Cat bypass
2. Leaves some power on the table

Cat bypass
Pro's
1. Raw sound
2 100% free flow
3. The most power you will be able to get out of the part
Con's
1. Smell
2. Check engine light
3. Issues with emissions in some states

If it is not a track only car we highly suggest going with the sport cats. It is less of a headache for emissions, CEL, and smell. Also if you are going with cat bypass normally you will go with a performance muffler or no muffler. If it is a track only car to get the real benefits of the Cat bypass you should go with the full exhaust and you might end up with going over DB ratings at some tracks. We do make some turn down tips to help out with sound but now you are fighting sound as well.

I hope this helps
I'd add that in a turbo car the extreme volume is significantly muted vs in an NA car due to the turbos. Also - with the O2/mini cat bungs the CEL is a non issue.
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Old 02-14-2018, 10:16 PM
  #18  
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Originally Posted by R_Rated View Post
Not at all. In every front engine car the small was always significant. When I had Soul Race headers on my 991 there was no smell from in the car while driving. There was no exhaust leaks so I don't know the scientific reason.... I just know what I smelled.
I would say that the smell issue has much more to do with the ecu calibration in whatever front engine car(s) you are referring to. The Porsche may self adjust for the mods much more accurately and keep the a/f ratio in check. Many cars are significantlyricher than optimal in stock form anyway, in an effort to reduce detonatin (pinging). The relative positon of the engine cannot possibly impact the smell any more than the color of the interior in the car would.
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