Muffler Bypass
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Instructor
Joined: Oct 2015
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yes but still not a real deal bypass pipes without any sound deadening or muffler as silencer
I think the stock PSE has an inherent bypass once you press the button?
PCA Spotlight: Cayman GT4 technical analysis - YouTube (12:14)
PCA Spotlight: Cayman GT4 technical analysis - YouTube (12:14)
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The way the exhaust is routed in the GT4 is totally different then the 911. In the 911 there are the side mufflers which are easy to bypass for us in the gt4 all we have is a center muffler. Only way to by pass our center muffler is to cut the exhaust up and reroute the pipe bypass to not tie back through the muffler and just the tips. Or just a straight piped car with cats.
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^Correct. 991 GT3 has (2) side mufflers and (1) Center muffler. The center muffler was mostly to meet Eurpoean sound requirements so bypassing was easy.
I look at a bypass on the Gt4 as going catless which is far from what bypassing is but you will get the change in sound on a similar basis
I look at a bypass on the Gt4 as going catless which is far from what bypassing is but you will get the change in sound on a similar basis
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You may want to look at an exhaust system with no flaps.......does the same without having to cut your stock PSE. If you don't like it you can always go back. I have the Cargraphics Cup Race exhaust on my GT4 coupled with 200-cel cat headers. Sound is great and you can live everyday with it. Had to break-in the mufflers but now the sounds is sooo much better.
BTW.....the stock GT4 PSE system is not 100% bypass....when you activate the PSE you still have a fair amount of exhaust gas flowing through the longer / muffled route.
BTW.....the stock GT4 PSE system is not 100% bypass....when you activate the PSE you still have a fair amount of exhaust gas flowing through the longer / muffled route.
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You may want to look at an exhaust system with no flaps.......does the same without having to cut your stock PSE. If you don't like it you can always go back. I have the Cargraphics Cup Race exhaust on my GT4 coupled with 200-cel cat headers. Sound is great and you can live everyday with it. Had to break-in the mufflers but now the sounds is sooo much better.
BTW.....the stock GT4 PSE system is not 100% bypass....when you activate the PSE you still have a fair amount of exhaust gas flowing through the longer / muffled route.
BTW.....the stock GT4 PSE system is not 100% bypass....when you activate the PSE you still have a fair amount of exhaust gas flowing through the longer / muffled route.
Also - how much weight does the Cup exhaust save over the OEM?
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Ours isnt a full bypass, but it definitely shaves weight and give the car a great sound.
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The Cup exhaust from Cargraphics doesn't use valves. You basically take out the whole OEM system (including valves). If you want to go back you can always sell the exhaust and get some of the money back....but once you have it on the car you wont want to take it off...unless you want to sell the car without the system.
To be honest my reasoning for this type of exhaust is because the first thing I was doing ALL the time when using the car was activating the PSE...and the car wasn't that loud either with the OEM exhaust. I also have headers with cats which lower the volume a bit (compared to Race headers) and makes this exhaust viable for everyday use. Other bonuses are that single path (without valves/flaps) exhaust systems will always produce more power and have lower weight....besides costing less. As for weight compared to OEM I didn't weight them but easy +20 pounds off.
If you go to this link on Facebook you can see a video of my car on a Mustang Dyno...too bad the dyno is very noisy:
https://www.facebook.com/fiebruz/videos/603772266438397/
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^ The tune will not make it louder but Fabspeed has some clips with their race headers - sound quite a bit louder but I do not find it offensive - I just elect not run my car on the street w/o cats.