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I am seriously thinking about getting the Fabspeed secondary cat bypass exhaust parts for my Cayenne S as its just too quiet! A little extra grunt would be nice too, so I was thinking the package with the air filters and maybe the ECU re-map too, but I was concerned about the smog testing here in California. I know technically its not approved, but wondering if anyone out there has experience with this? I know a good specialist in my area, who could probably help with the visual inspection part, but wondering on the actual emissions side of things - what happens? Will it fail? How do other people get around this? Smog it before the bypass is fitted and swap it back in 2 years when it goes in again?
Any experiences would be great. Also, does it make any difference in discernible performance? Or is it really an audible change only?
I am seriously thinking about getting the Fabspeed secondary cat bypass exhaust parts for my Cayenne S as its just too quiet! A little extra grunt would be nice too, so I was thinking the package with the air filters and maybe the ECU re-map too, but I was concerned about the smog testing here in California. I know technically its not approved, but wondering if anyone out there has experience with this? I know a good specialist in my area, who could probably help with the visual inspection part, but wondering on the actual emissions side of things - what happens? Will it fail? How do other people get around this? Smog it before the bypass is fitted and swap it back in 2 years when it goes in again?
Any experiences would be great. Also, does it make any difference in discernible performance? Or is it really an audible change only?
on Cayenne Turbo, it passes smog in California without any hookups or favors - I did it at a random gas station at Walnut Creek because it was the closest to where my wife shopped. Similar in British Columbia, Canada - no issues. It's invisible because it's secondary cat bypass, and primary cat is all that's needed to pass sniffer with a good safety margin. There are no electronic sensors for the secondary cat as well, so removing it appears to make no detectable difference. Cannot comment on Cayenne S, but on Turbo it's definitely worth it for sound and throttle response improvement. Probably a smaller benefit on a naturally aspirated engine, though.
on Cayenne Turbo, it passes smog in California without any hookups or favors - I did it at a random gas station at Walnut Creek because it was the closest to where my wife shopped. Similar in British Columbia, Canada - no issues. It's invisible because it's secondary cat bypass, and primary cat is all that's needed to pass sniffer with a good safety margin. There are no electronic sensors for the secondary cat as well, so removing it appears to make no detectable difference. Cannot comment on Cayenne S, but on Turbo it's definitely worth it for sound and throttle response improvement. Probably a smaller benefit on a naturally aspirated engine, though.
I have been thinking about doing the same but am concerned about drone and excessive noise.
My GTS has PSE and I like the ability to just turn up the volume when I want. Secondary by pass is a permanent change.
Can you chime in about drone at city cruising and highway speeds? Like most people, drone would drive me crazy.
Our 958 Cayenne S/GTS Secondary Catbypass Pipes are a fantastic upgrade to pick up additional power (+11whp) and a deeper, throatier exhaust tone.
Install is very straightforward by way of a direct bolt-on replacement - no cutting/welding required!
Also, NO Check Engine Light due to the Secondary Catalytic Converters not being monitored/read by the ECU.
Constructed from T403L Stainless Steel right here in Fort Washington, PA and backed by Fabspeed's Limited Lifetime Warranty.
As far as SMOG, I usually recommend guys use a performance oriented shop. They're also pretty easy to install/remove too so we have quite a few guys swap them out every few years, worst case. No issues with emissions/sniffer tests.
I may not be speaking for everyone, but for majority of us with 958 S and GTS, our biggest reservation is every day driving noise, sound and drone.
I have PSE and with valves open, the exhaust is perfect. I would consider the bypass if in closed-valve mode, I can drive around town without attracting attention and can drive at normal speed without seeming like some boy racer.
I may not be speaking for everyone, but for majority of us with 958 S and GTS, our biggest reservation is every day driving noise, sound and drone.
I have PSE and with valves open, the exhaust is perfect. I would consider the bypass if in closed-valve mode, I can drive around town without attracting attention and can drive at normal speed without seeming like some boy racer.
I can't speak for GTS or S, unfortunately (or luckily LOL) but on Turbo it adds very little in volume. Basically, I do not hear the engine at all with windows up during normal driving with sport mode off. With secondary bypass and sport mode on it sounds like AMG GLE63 with sport mode off and stock exhaust. Where it did make noticeable change is loudness of start up. Not sure why, but the effect there was bigger than during driving. There is absolutely no drone either in sport or non-sport mode. I think it's a much better bang for the buck than changing stock muffler because it's a cheaper and easier to install part, and stock sound is good enough. This just makes it a little bit louder plus adds some (very little) HP - win-win.
I can't speak for GTS or S, unfortunately (or luckily LOL) but on Turbo it adds very little in volume. Basically, I do not hear the engine at all with windows up during normal driving with sport mode off. With secondary bypass and sport mode on it sounds like AMG GLE63 with sport mode off and stock exhaust. Where it did make noticeable change is loudness of start up. Not sure why, but the effect there was bigger than during driving. There is absolutely no drone either in sport or non-sport mode. I think it's a much better bang for the buck than changing stock muffler because it's a cheaper and easier to install part, and stock sound is good enough. This just makes it a little bit louder plus adds some (very little) HP - win-win.
I know that GTS and Turbos with Sport package (I think) start up with valves open. I know my GTS does.. but they close within first few seconds.
I am seriously thinking about getting the Fabspeed secondary cat bypass exhaust parts for my Cayenne S as its just too quiet! A little extra grunt would be nice too, so I was thinking the package with the air filters and maybe the ECU re-map too, but I was concerned about the smog testing here in California. I know technically its not approved, but wondering if anyone out there has experience with this? I know a good specialist in my area, who could probably help with the visual inspection part, but wondering on the actual emissions side of things - what happens? Will it fail? How do other people get around this? Smog it before the bypass is fitted and swap it back in 2 years when it goes in again?
Any experiences would be great. Also, does it make any difference in discernible performance? Or is it really an audible change only?
I did this exact mod on my 2012 Cayenne S and posted up a thread with the obligatory “Before & After” videos. I don’t have PSE on my PiG so I was looking for a throatier exhaust note, and these are perfect. And MaxLTV is absolutely right that there is no drone on the highway with these pipes. This is my winter DD in Chicago when my 997.2 4S Cab is happily holed up for the winter, and I don’t hear any drone at highway speed on my 50-mile commute in my PiG. Overall, I love this simple mod as it gives my non-PSE Cayenne S a great growl for a lot less than an aftermarket PSE install
I install fabspeed secondary cat bypass on my 2013 Cayenne S and I don't have PSE, the big different was when you start up you car only, When you normal drive you will not hear any big different!
Is there even a difference between the turbo and S bypass design? Will they fit both cars? I’m asking this bc there is a company that sells these for the turbo model cars for a good price. They’re not on eBay btw.
EDIT: I found my own answer with PET. They are the same.
I did this exact mod on my 2012 Cayenne S and posted up a thread with the obligatory “Before & After” videos. I don’t have PSE on my PiG so I was looking for a throatier exhaust note, and these are perfect. And MaxLTV is absolutely right that there is no drone on the highway with these pipes. This is my winter DD in Chicago when my 997.2 4S Cab is happily holed up for the winter, and I don’t hear any drone at highway speed on my 50-mile commute in my PiG. Overall, I love this simple mod as it gives my non-PSE Cayenne S a great growl for a lot less than an aftermarket PSE install
Ah, those videos? I am pretty sure I spotted on that is actually linked on the Fabspeed site itself! Does sound good though!
I dont have PSE and while I commend the Porsche engineers for making it so quiet on the inside, the only real option is to have the window open, and then you get that not-so-nice direction injection clatter if you are stopped in traffic. Certainly sounds good and if there is little or no drone, sounds like a plan to me!
I've got a GTS and the cat bypass done. It's definitely VERY loud on cold starts. I've had neighbors 2-3 houses down comment on it but in a "dude thats awesome" kinda way. No drone when driving around. It just makes the exhaust louder and more throaty.
I've got a GTS and the cat bypass done. It's definitely VERY loud on cold starts. I've had neighbors 2-3 houses down comment on it but in a "dude thats awesome" kinda way. No drone when driving around. It just makes the exhaust louder and more throaty.
Good to know; our '14 CS is the wife's DD, so I'm thinking about going the HHR cat bypass route. Hank builds his versions with resonators, which should make things sound a little less aggressive.
Our 958 Cayenne S/GTS Secondary Catbypass Pipes are a fantastic upgrade to pick up additional power (+11whp) and a deeper, throatier exhaust tone.
Install is very straightforward by way of a direct bolt-on replacement - no cutting/welding required!
Also, NO Check Engine Light due to the Secondary Catalytic Converters not being monitored/read by the ECU.
Constructed from T403L Stainless Steel right here in Fort Washington, PA and backed by Fabspeed's Limited Lifetime Warranty.
As far as SMOG, I usually recommend guys use a performance oriented shop. They're also pretty easy to install/remove too so we have quite a few guys swap them out every few years, worst case. No issues with emissions/sniffer tests.
So just to be clear (for those of us in CA), does that mean it will pass CA smog texsting or that we should expect to remove them before the testing and replace afterwards?
01-10-2018, 02:47 AM
Fabspeed secondary cat bypass?
