Fabspeed Bypass Pipes Installed on my GTS - Before & After Video
#16
12-02-2009, 09:47 PM
I added the cat bypass pipes to an 08 gts last summer.
fabspeed thought the rattle was from the sport valve, I unhooked the vacuum hose that activates the sport valve and nothing changed.
I ended up putting in fabspeed's cayenne s exhaust, which is not a bolt on application for the gts, but will fit with some welding.
in the end, the best thing I did was switch the exhaust, the sound is like a 60's era corvette.
the rattle is still there, but only on a cold start after more than 20 hours or so of sitting. I've gotten used to it.
the best guess I've heard is that the rattle is from trying to warm up the 4 cat converters as fast as possible after start for emission purposes. with only 2 cats the pipes get overloaded and rattle.
fabspeed thought the rattle was from the sport valve, I unhooked the vacuum hose that activates the sport valve and nothing changed.
I ended up putting in fabspeed's cayenne s exhaust, which is not a bolt on application for the gts, but will fit with some welding.
in the end, the best thing I did was switch the exhaust, the sound is like a 60's era corvette.
the rattle is still there, but only on a cold start after more than 20 hours or so of sitting. I've gotten used to it.
the best guess I've heard is that the rattle is from trying to warm up the 4 cat converters as fast as possible after start for emission purposes. with only 2 cats the pipes get overloaded and rattle.
#17
12-03-2009, 08:01 AM
I added the cat bypass pipes to an 08 gts last summer.
fabspeed thought the rattle was from the sport valve, I unhooked the vacuum hose that activates the sport valve and nothing changed.
I ended up putting in fabspeed's cayenne s exhaust, which is not a bolt on application for the gts, but will fit with some welding.
in the end, the best thing I did was switch the exhaust, the sound is like a 60's era corvette.
the rattle is still there, but only on a cold start after more than 20 hours or so of sitting. I've gotten used to it.
the best guess I've heard is that the rattle is from trying to warm up the 4 cat converters as fast as possible after start for emission purposes. with only 2 cats the pipes get overloaded and rattle.
fabspeed thought the rattle was from the sport valve, I unhooked the vacuum hose that activates the sport valve and nothing changed.
I ended up putting in fabspeed's cayenne s exhaust, which is not a bolt on application for the gts, but will fit with some welding.
in the end, the best thing I did was switch the exhaust, the sound is like a 60's era corvette.
the rattle is still there, but only on a cold start after more than 20 hours or so of sitting. I've gotten used to it.
the best guess I've heard is that the rattle is from trying to warm up the 4 cat converters as fast as possible after start for emission purposes. with only 2 cats the pipes get overloaded and rattle.
OEM with bypass
http://www.youtube.com/watch?v=FG1-LKfYK10
Fabspeed exhaust with bypass
http://fabspeed.com/videos/Cayenne%2...ss%20Video.wmv
What do you guys think?
#18
12-03-2009, 11:21 AM
my experience was that the cat bypass let more sound through but didn't change the overall tone of the exhaust. porsche did a nice job with the exhaust, making it suitable for a family suv/quiet neighborhood type sound but still giving an aggressive sound under acceleration.
the fabspeed muffler adds aggressive v-8 sound even at idle, in fact the most compliments I've had from friends and strangers is from the idle.
and under acceleration the sound is fantastic, even slow starts from a stop light sound great.
unfortunately for me I was a guinea pig on this one, fabspeed didn't know at the time the gts system was different. looks like now they have a bolt on system and maybe its been tuned to the gts. my gts kind of overwhelms the muffler from 3800 to 4300 rpm's and there is a raspy sound, before and after it sounds awesome.
so yes, I like the after market exhaust much better than the oem sport button system.
I didn't see a fabspeed video of the gts with the muffler, only the bypass pipes. the muffler videos look to be turbo and s models.
I'll try and get some video/sound of the exhaust I have posted.
the fabspeed muffler adds aggressive v-8 sound even at idle, in fact the most compliments I've had from friends and strangers is from the idle.
and under acceleration the sound is fantastic, even slow starts from a stop light sound great.
unfortunately for me I was a guinea pig on this one, fabspeed didn't know at the time the gts system was different. looks like now they have a bolt on system and maybe its been tuned to the gts. my gts kind of overwhelms the muffler from 3800 to 4300 rpm's and there is a raspy sound, before and after it sounds awesome.
so yes, I like the after market exhaust much better than the oem sport button system.
I didn't see a fabspeed video of the gts with the muffler, only the bypass pipes. the muffler videos look to be turbo and s models.
I'll try and get some video/sound of the exhaust I have posted.
#20
12-15-2009, 01:47 PM
my experience was that the cat bypass let more sound through but didn't change the overall tone of the exhaust. porsche did a nice job with the exhaust, making it suitable for a family suv/quiet neighborhood type sound but still giving an aggressive sound under acceleration.
the fabspeed muffler adds aggressive v-8 sound even at idle, in fact the most compliments I've had from friends and strangers is from the idle.
and under acceleration the sound is fantastic, even slow starts from a stop light sound great.
unfortunately for me I was a guinea pig on this one, fabspeed didn't know at the time the gts system was different. looks like now they have a bolt on system and maybe its been tuned to the gts. my gts kind of overwhelms the muffler from 3800 to 4300 rpm's and there is a raspy sound, before and after it sounds awesome.
so yes, I like the after market exhaust much better than the oem sport button system.
I didn't see a fabspeed video of the gts with the muffler, only the bypass pipes. the muffler videos look to be turbo and s models.
I'll try and get some video/sound of the exhaust I have posted.
the fabspeed muffler adds aggressive v-8 sound even at idle, in fact the most compliments I've had from friends and strangers is from the idle.
and under acceleration the sound is fantastic, even slow starts from a stop light sound great.
unfortunately for me I was a guinea pig on this one, fabspeed didn't know at the time the gts system was different. looks like now they have a bolt on system and maybe its been tuned to the gts. my gts kind of overwhelms the muffler from 3800 to 4300 rpm's and there is a raspy sound, before and after it sounds awesome.
so yes, I like the after market exhaust much better than the oem sport button system.
I didn't see a fabspeed video of the gts with the muffler, only the bypass pipes. the muffler videos look to be turbo and s models.
I'll try and get some video/sound of the exhaust I have posted.
#21
12-16-2009, 02:10 AM
Join Date: Jun 2009
Location: Greenwich, CT
Posts: 215
Rep Power: 24 
PLEASE post a video of your new setup.
Many of us here have yet to hear a GTS with a full muffler....dying to hear how it sounds.
Did you keep the Bypass Pipes in addition to the new muffler?
Many of us here have yet to hear a GTS with a full muffler....dying to hear how it sounds.
Did you keep the Bypass Pipes in addition to the new muffler?
#22
12-16-2009, 05:37 AM
What's rattling that a hanger would fix? If it's as simple as a hanger, any competent exhaust shop should be able to add one to the bypass pipes.
#23
12-16-2009, 08:25 PM
Join Date: Jun 2009
Location: Greenwich, CT
Posts: 215
Rep Power: 24
I don't believe the rattling of the Bypass Pipes has anything to do with the pipes physically banging against anything, like the transmission support, etc.
I inspected the install, and have since had my car on a lift to see that the pipes are indeed installed properly and have sufficient clearance from anything that could cause impact. There's about an inch of clearance between the bottom of the pipes and the transmission support for example.
I spoke with Alex at Fabspeed, and he told me that this is a fairly "common" situation. We both believe the noise is being caused by turbulence in the pipes on a cold start when a large volume of air passes through the pipes. Without the Cats (resonators) in the stock secondary pipes, there's nothing to slow the velocity of air down until it gets to the mufflers, thus potentially causing this turbulence.
On my GTS, the sound only lasts for about 3-5 secs and it also goes away if you put the car in Reverse.
Not sure why, but it does!
I inspected the install, and have since had my car on a lift to see that the pipes are indeed installed properly and have sufficient clearance from anything that could cause impact. There's about an inch of clearance between the bottom of the pipes and the transmission support for example.
I spoke with Alex at Fabspeed, and he told me that this is a fairly "common" situation. We both believe the noise is being caused by turbulence in the pipes on a cold start when a large volume of air passes through the pipes. Without the Cats (resonators) in the stock secondary pipes, there's nothing to slow the velocity of air down until it gets to the mufflers, thus potentially causing this turbulence.
On my GTS, the sound only lasts for about 3-5 secs and it also goes away if you put the car in Reverse.
Not sure why, but it does!
#25
12-17-2009, 10:18 AM
sorry about not posting. I took a couple videos but 6speed wouldn't let me post them. I guess I need to get a youtube account and then post a link? could someone verify this?
I also don't have enough posts to respond to pm's.
my guess on the very annoying rattle is that the emissions system is trying to heat up the cats on start up. that could lead to the turbulence theory above, but that doesn't explain why people with turbos or s models haven't experienced that rattle.
the rattle will always be there until someone makes bypass pipes for the gts, fabspeed's are made for the turbo and s models which seem to be slightly different.
changing the exhaust didn't fix the rattle, but also didn't make the rattle any louder than it was before. as I posted before I'm very happy with the exhaust. the post 'new techart exhaust clips' sounds much louder than my fabspeed exhaust.
polar993, your location reads san fran, you should call up Sharkwerks in Fremont and see if they will build an exhaust. they don't have a gts exhaust and maybe you can workout some deal with your gts as a test model. I can't imagine any place better.
I also don't have enough posts to respond to pm's.
my guess on the very annoying rattle is that the emissions system is trying to heat up the cats on start up. that could lead to the turbulence theory above, but that doesn't explain why people with turbos or s models haven't experienced that rattle.
the rattle will always be there until someone makes bypass pipes for the gts, fabspeed's are made for the turbo and s models which seem to be slightly different.
changing the exhaust didn't fix the rattle, but also didn't make the rattle any louder than it was before. as I posted before I'm very happy with the exhaust. the post 'new techart exhaust clips' sounds much louder than my fabspeed exhaust.
polar993, your location reads san fran, you should call up Sharkwerks in Fremont and see if they will build an exhaust. they don't have a gts exhaust and maybe you can workout some deal with your gts as a test model. I can't imagine any place better.
#26
12-17-2009, 01:32 PM
Join Date: Jun 2009
Location: Greenwich, CT
Posts: 215
Rep Power: 24
The GTS always starts in Normal mode (not sure about other Cayenne models), and the rattle ONLY happens on a cold start, lasting a couple of seconds.
#27
12-17-2009, 01:38 PM
Join Date: Jun 2009
Location: Greenwich, CT
Posts: 215
Rep Power: 24
z145433, to post your video you should indeed upload it to YouTube first then either just post a link you your video or embed it within your post via HTML.
Did you still have the Bypass Pipes in place in conjunction with your Fabspeed Mufflers, or did you put back your stock Secondary Cats?
I'll give the Sharkswerks guys a call, though considering the GTS is my wife's car, I'm not too sure I want it to be a test car for them. We'll see....
Did you still have the Bypass Pipes in place in conjunction with your Fabspeed Mufflers, or did you put back your stock Secondary Cats?
I'll give the Sharkswerks guys a call, though considering the GTS is my wife's car, I'm not too sure I want it to be a test car for them. We'll see....
sorry about not posting. I took a couple videos but 6speed wouldn't let me post them. I guess I need to get a youtube account and then post a link? could someone verify this?
I also don't have enough posts to respond to pm's.
my guess on the very annoying rattle is that the emissions system is trying to heat up the cats on start up. that could lead to the turbulence theory above, but that doesn't explain why people with turbos or s models haven't experienced that rattle.
the rattle will always be there until someone makes bypass pipes for the gts, fabspeed's are made for the turbo and s models which seem to be slightly different.
changing the exhaust didn't fix the rattle, but also didn't make the rattle any louder than it was before. as I posted before I'm very happy with the exhaust. the post 'new techart exhaust clips' sounds much louder than my fabspeed exhaust.
polar993, your location reads san fran, you should call up Sharkwerks in Fremont and see if they will build an exhaust. they don't have a gts exhaust and maybe you can workout some deal with your gts as a test model. I can't imagine any place better.
I also don't have enough posts to respond to pm's.
my guess on the very annoying rattle is that the emissions system is trying to heat up the cats on start up. that could lead to the turbulence theory above, but that doesn't explain why people with turbos or s models haven't experienced that rattle.
the rattle will always be there until someone makes bypass pipes for the gts, fabspeed's are made for the turbo and s models which seem to be slightly different.
changing the exhaust didn't fix the rattle, but also didn't make the rattle any louder than it was before. as I posted before I'm very happy with the exhaust. the post 'new techart exhaust clips' sounds much louder than my fabspeed exhaust.
polar993, your location reads san fran, you should call up Sharkwerks in Fremont and see if they will build an exhaust. they don't have a gts exhaust and maybe you can workout some deal with your gts as a test model. I can't imagine any place better.
#28
12-17-2009, 01:51 PM
During a cold start, mine sounds its like its BANGING hard against some metal, it goes DA DA DA DA DA... Is that rattling sound you are talking about?
#29
12-17-2009, 02:01 PM
Former Vendor
Hi guys, I understand their is a problem with the rattle you are getting and I have looked into this some more and I cant say why its happening or where it's coming from. We have installed and sold many of these and I have not had anyone bring up this issue. It makes sense that it happens when you install the 2ndary catbypass pipes but only a few people have the problem which is strange. We have a 2006 Cayenne Turbo in our shop now and it has our 2ndary Bypass Pipes and our Maxflo Mufflers and it has no issues with rattling on cold start. I will look into this further and try to figure out a solution.
Thanks,
Thanks,
#30
12-17-2009, 02:10 PM
Hi guys, I understand their is a problem with the rattle you are getting and I have looked into this some more and I cant say why its happening or where it's coming from. We have installed and sold many of these and I have not had anyone bring up this issue. It makes sense that it happens when you install the 2ndary catbypass pipes but only a few people have the problem which is strange. We have a 2006 Cayenne Turbo in our shop now and it has our 2ndary Bypass Pipes and our Maxflo Mufflers and it has no issues with rattling on cold start. I will look into this further and try to figure out a solution.
Thanks,
Thanks,
Previously Fabspeed mentioned the banging noise is from the pipe hitting the cross bar. And the solution is to pushing up the pipe as high as possible then tighten. My dealer has reinstalled the pipe couple times but the noise remains. I'm working on a deal with jeremy for the full performanc package and hopefully when i bring the car over to your shop, we can find a resolution.
John