Notices
997 GT2/GT3 Forum 2005-2012
Sponsored by:
Sponsored by: Porsche North Houston

Bypass Question

Thread Tools
 
Search this Thread
 
Old 04-29-2017, 06:14 PM
  #1  
Sk8erpope
Intermediate
Thread Starter
 
Sk8erpope's Avatar
 
Join Date: Dec 2016
Location: Heidelberg, Germany
Posts: 35
Received 50 Likes on 11 Posts
Default Bypass Question

Hi,

yesterday I finally had the time to install my EVOX bypass on my 2008 GT3. I'm happy with the sound so far, but around 3000rpm I have an annoying cabine resonance. My exhaust is "unplugged".

I'm not sure if this is a general problem when using a bypass or is this caused only from the EVOX bypass, because the tube diamter is bigger compared to Sharkwerks and all the other manufacturer.

Already think about to swith to another bypass

What do you think?
Attached Images   
Old 04-29-2017, 08:26 PM
  #2  
ngng
Drifting
 
ngng's Avatar
 
Join Date: Sep 2013
Location: Bay Area, CA
Posts: 2,064
Received 307 Likes on 186 Posts
Default

let's talk about those welds though
Old 04-29-2017, 11:10 PM
  #3  
jaundice
Pro
 
jaundice's Avatar
 
Join Date: Mar 2015
Location: DFW
Posts: 728
Likes: 0
Received 6 Likes on 4 Posts
Default

I have a GMG bypass sitting in my garage. PM if interested.
Old 04-30-2017, 12:40 AM
  #4  
ilko
Agent Orange
Rennlist Member
 
ilko's Avatar
 
Join Date: Jun 2006
Posts: 16,191
Received 555 Likes on 199 Posts
Default

Here's my experience with 997 GT3 exhausts and drone (resonance):

My previous 2010 GT3 came with an RSS center muffler delete. It did have a bit of a drone at low RPM. Not terrible but noticeable. And I think that's true for all center delete set ups. It's up to the individual to decide how much is acceptable. Some people hate drone, others tolerate it more or less.

My current 2010 RS has the stock mufflers with aftermarket headers & 200 cell cats. Zero drone throughout the rev range. Last year I installed a box that controls the side muffler flappers from the cabin. It's a nifty gadget! With the flappers open at low RPM the sound is much deeper and angry, but there is drone present.

YMMV
Old 04-30-2017, 04:09 AM
  #5  
Sk8erpope
Intermediate
Thread Starter
 
Sk8erpope's Avatar
 
Join Date: Dec 2016
Location: Heidelberg, Germany
Posts: 35
Received 50 Likes on 11 Posts
Default

Thanx guys for your feedback.

@jaundice: I believe the GMG bypass is pretty much the same design as the EVOX bypass, so I think it will make no difference sound- and dronewise. But thanx for your offer.

@ilko: I can controll my flappers with a button in the dashborad. So when they are open, I have a drone around 3000rpm, when I close the flappers there is a minimum drone, not to bad but you can feel and hear it.

I believe the tube size of the EVOX bypass is to big, which is probably responsable for the drone. On the SW or the RSS bypass for example, the tubes are pretty small compared to the EVOX. So this is maybe the difference. Maybe I'm wrong, but that's the only reason I can imagine.
Old 04-30-2017, 12:06 PM
  #6  
Speedster911
Rennlist Member
 
Speedster911's Avatar
 
Join Date: Oct 2013
Location: Planet Earth
Posts: 1,015
Received 110 Likes on 61 Posts
Default

No drone with SW bypass.
Old 04-30-2017, 08:07 PM
  #7  
RAudi Driver
Rennlist Member
 
RAudi Driver's Avatar
 
Join Date: Jan 2011
Location: West Coast
Posts: 9,128
Received 2,923 Likes on 1,730 Posts
Default

No drone with my Rss either.

I keep hearing that the GMG has a drone and those pipes look like the GMG's except that they reduce in size on exit, which sounds like a recipe for turbulence.

And as NGNG said, that is some sloppy work.
Old 05-01-2017, 12:21 AM
  #8  
deutschmick
Rennlist Member
 
deutschmick's Avatar
 
Join Date: Nov 2006
Location: TX
Posts: 3,255
Received 117 Likes on 81 Posts
Default

Originally Posted by Speedster911
No drone with SW bypass.
+1
Old 05-01-2017, 11:14 AM
  #9  
John@Fabspeed
Basic Sponsor
Rennlist
Site Sponsor

 
John@Fabspeed's Avatar
 
Join Date: Nov 2006
Location: Fort Washington, Pa
Posts: 4,717
Received 56 Likes on 40 Posts
Default

Sounds is always going to be subjective, but I haven't heard of any drone complaints with our center muffler bypass either.


__________________
Porsche Performance Specialist
John@Fabspeed.com
215-618-9796

Fabspeed Motorsport USA
155 Commerce Drive Fort Washington, PA 19034
www.Fabspeed.com


Old 05-01-2017, 12:47 PM
  #10  
hermz
5th Gear
 
hermz's Avatar
 
Join Date: Apr 2017
Location: San Diego
Posts: 5
Likes: 0
Received 0 Likes on 0 Posts
Default

Originally Posted by jaundice
I have a GMG bypass sitting in my garage. PM if interested.
Sent you a message about this in your profile. Thanks.
Old 05-01-2017, 03:58 PM
  #11  
DWNDRAFT
Instructor
 
DWNDRAFT's Avatar
 
Join Date: Jan 2016
Posts: 140
Received 15 Likes on 9 Posts
Default

I have the same setup. Fantastic noise when you get on it, but realtivly quite below 3500rpms

Ran it "unplugged" today, and while it sounds great, there is some drone at 3000rpms +\- 300, under load.
It can ger a little tiresome on the freeway.

I am thinking about the remote switch, could make some sense here.
Old 05-01-2017, 09:23 PM
  #12  
jaundice
Pro
 
jaundice's Avatar
 
Join Date: Mar 2015
Location: DFW
Posts: 728
Likes: 0
Received 6 Likes on 4 Posts
Default

Originally Posted by hermz
Sent you a message about this in your profile. Thanks.
I didn't get anything. Tried to PM you but says I can't.
Text me at (214) 502-7784 if interested.

Sorry to hijack thread
Old 05-03-2017, 08:25 AM
  #13  
trendy996
Banned
 
trendy996's Avatar
 
Join Date: Oct 2011
Location: Holy City, South Carolina
Posts: 2,391
Likes: 0
Received 1 Like on 1 Post
Default

I have a fabspeed center delete for 500
Old 05-03-2017, 12:52 PM
  #14  
Sleepy996
Pro
 
Sleepy996's Avatar
 
Join Date: Oct 2014
Location: FL
Posts: 666
Received 118 Likes on 56 Posts
Default

If its too loud unplugged why not plug the valves back in for roadtrips etc and unplug for track use or weekend drives ?
Old 05-03-2017, 05:59 PM
  #15  
MJFDDS
Rennlist Member
 
MJFDDS's Avatar
 
Join Date: Mar 2008
Location: Southern California
Posts: 375
Received 41 Likes on 25 Posts
Default

On my RSS setup I actually removed one of the vacuum hoses from the valve, but left the other intact. It's an in-between for having the sport button unplugged since you still have one valve functioning. And if you want it a tad louder you can always activate the sport button which will open the other valve.


Quick Reply: Bypass Question



All times are GMT -3. The time now is 08:52 PM.