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Yeah it will drone terribly and you'll still have to get a custom tune to prevent a CEL without the benefit of increased flow an aftermarket exhaust provides.
Not worth it. Spend the extra for a decent new exhaust.
Shifter is correct about the tune, with catbypass pipes you will throw a CEL for cat efficiency. As far as the drone, you'll get some but the stock muffler is pretty restrictive so it would cut it down some.
Depending on what the car gets used for I would highly recommend our Supersport X-Pipe with Cats. Our X-Pipe makes +25 hp and +31 ft/lbs in addition to the improved exhaust tone!
Let me know if this is something you'd be interested in or if you have any questions. I'm happy to assist!
Stock muffler isn’t restrictive at all. I’ve tested them all and it’s the best flowing turbo muffler Porsche has build so far. Sounds much louder without cats but the same tone remains. FYI the 991 TT stock cats are actually 997.2 TT cats.
Stock muffler isn’t restrictive at all. I’ve tested them all and it’s the best flowing turbo muffler Porsche has build so far. Sounds much louder without cats but the same tone remains. FYI the 991 TT stock cats are actually 997.2 TT cats.
Is it possible to just replace the stock cats with high flow and re use stock muffler?
Stock muffler isn’t restrictive at all. I’ve tested them all and it’s the best flowing turbo muffler Porsche has build so far. Sounds much louder without cats but the same tone remains. FYI the 991 TT stock cats are actually 997.2 TT cats.
+2. Increased sound and restriction delete. WIN WIN
Here is a dyno chart with the results of a stock car that has cats vs. the same stock car with the cat bypass pipes that we make. The dotted line is the stock run.
You will notice that the car gets up on power a lot quicker with the cat-bypass and makes more power. The car also runs leaner with the cat bypass which can easily be corrected with a tune. With the correct tune it is a great low cost upgrade for those customers that race their cars.
Yeah it will drone terribly and you'll still have to get a custom tune to prevent a CEL without the benefit of increased flow an aftermarket exhaust provides.
Not worth it. Spend the extra for a decent new exhaust.
Probably the worst info and advice I've ever read.
Ready for the perfect welding job
I am testing following / remove the second cat / System is OBD complaint with the pre cat in front /half restriction/
Hope next month i am ready to see results (i use cheap used cats from a 997.2 DFI Engine....)
Last edited by winnigt2; Jul 22, 2019 at 02:32 PM.
