Porsche 911 UK Enthusiasts Online Community Discussion Forum GB
Welcome to the @Porsche911UK website. Register a free account today to become a member! Sign up is quick and easy, then you can view, participate in topics and posts across the site that covers all things Porsche.
Already registered and looking to recovery your account, select 'login in' and then the 'forget your password' option.
911 PSE Exhaust Hack aka the 'Gundo Hack'
- Thread starter Porsche News
- Start date
I've had the Hayward and Scott 1.5" hack also on my 997.1 C2S, overall would recommend it highly. I did notice a slight resonance/drone at around 3200rpm +/- 100rpm on a recent trip; dropped off quickly outside these revs but happened to be nearly bang on cruising speed on Belgium's motorways :frustrated: It did give me a slight head-fuzz, but other than that have not had any problem with drone.
Mates in a following car said they could certainly hear when I was about, and especially when I hit the gas! Purposeful, not 'boy racer'. :thumbs:
Mates in a following car said they could certainly hear when I was about, and especially when I hit the gas! Purposeful, not 'boy racer'. :thumbs:
JohnnyDangerous
Estoril
- Joined
- 12 Jun 2013
- Messages
- 3,620
Much prefer the PSE style hack, we do loads of stuff like this, at the moment the M3 boys are all having their rear boxes cut open and some of the sound chambers by-passed, I reckon about 3 hours to TIG weld the boxes up and whatever time it takes to remove the exhaust, you would have to budget for a fitting kit for the exhaust.
Gumtree / Gundo Hack.
Happy days!
My silencers are splitting and starting to leak so I thought I'd take a look on Gumtree for a replacement. Brought a 3.6 X51 complete system thats hardly been used for £300. Result.
Now the big question, I'm thinking of having it Gundo'd before it's fitted as I want more noise, but I also don't want it to upset the neighbours (too much) so should I go for a 1½" or 2" pipe?
Happy days!
My silencers are splitting and starting to leak so I thought I'd take a look on Gumtree for a replacement. Brought a 3.6 X51 complete system thats hardly been used for £300. Result.
Now the big question, I'm thinking of having it Gundo'd before it's fitted as I want more noise, but I also don't want it to upset the neighbours (too much) so should I go for a 1½" or 2" pipe?
demon
Nurburgring
- Joined
- 19 Apr 2011
- Messages
- 436
Keep it small - hacks with bigger pipes really don't sound particularly refined
- I'd also look into whether bridging between the two pipes vs bypassing off the top corner/shoulder of the muffler to the outflow pipe (i.e. more akin to the genuine PSE) has a better result to the final sound
I previously had a "bridged" set - fell out of love with the sound after a while, as while I'd gained a bit of gruff and grumble/drama around town I'd lost the Jeckyll/Hyde howl that builds as you really come onto the variocam - the bridging tube itself also started to deteriorate/rot rather quickly, so material will be a consideration as well
- I'd also look into whether bridging between the two pipes vs bypassing off the top corner/shoulder of the muffler to the outflow pipe (i.e. more akin to the genuine PSE) has a better result to the final sound
I previously had a "bridged" set - fell out of love with the sound after a while, as while I'd gained a bit of gruff and grumble/drama around town I'd lost the Jeckyll/Hyde howl that builds as you really come onto the variocam - the bridging tube itself also started to deteriorate/rot rather quickly, so material will be a consideration as well
infrasilver
Moderator
- Joined
- 4 Oct 2010
- Messages
- 9,934
On my 3.6 I went for the 2" bypass, the PSE pipe is 2.5" IIRC but I wanted something slightly quieter. I'm really happy with the sound it now produces and is not too loud when tootling about but when it at WOT it's great, which is all the time.. :wink:
I went to a show a while back and I got talking to a guy with a 996 which had been hacked with a large bore pipe and TBH it sounded a bit like a tractor... I am not sure how loud it was when it was revving but at tick over it sounded harsh for want of a better description.
When looking into this for my 997.1, it's my understanding that you have to be sure what type of hack you're referring to when it comes to the diameter of the bypass.
If you use the PSE port (often called the "banana" hack) and therefore have the bypass between that and the inlet pipe, the gases which go through it are bypassing "some" of the chambers inside the muffler (I think its 2 out of 3).
However, if you have the "gundo" hack which is a straight or slightly curved bypass pipe between the inlet and output pipes of the muffler, the gases which go through it are bypassing "all" of the muffler.
What proportion of gases go through these bypasses will obviousy vary (mainly due to throttle opening) but it's my understanding that a larger diameter bypass is used on the banana hack compared to the gundo hack, which makes sense, as the banana hack doesnt bypass all the chambers the muffler.
Therefore when people say they have a 2-2.5" bypass on a PSE port (banana) hack, they could well end up with a very similar sounding result (in terms of volume and tone) to somebody who has a 1.5-2" bypass on the gundo type hack.
I have read there are subtle differences and that the banana hack is a more refined racket than a gundo hack which does make sense given that hack still uses the muffler to some degree, but I have a gundo 1.5" and find it suitably sporting and interesting, but not obnoxiously loud at all.
I read a lot of posts on various forums and I came away thinking that the gundo range that would please most people was a 1.5-1.75" bypass (2" if you like loud) and that the same could be said of a banana hack at 2-2.5."
If you use the PSE port (often called the "banana" hack) and therefore have the bypass between that and the inlet pipe, the gases which go through it are bypassing "some" of the chambers inside the muffler (I think its 2 out of 3).
However, if you have the "gundo" hack which is a straight or slightly curved bypass pipe between the inlet and output pipes of the muffler, the gases which go through it are bypassing "all" of the muffler.
What proportion of gases go through these bypasses will obviousy vary (mainly due to throttle opening) but it's my understanding that a larger diameter bypass is used on the banana hack compared to the gundo hack, which makes sense, as the banana hack doesnt bypass all the chambers the muffler.
Therefore when people say they have a 2-2.5" bypass on a PSE port (banana) hack, they could well end up with a very similar sounding result (in terms of volume and tone) to somebody who has a 1.5-2" bypass on the gundo type hack.
I have read there are subtle differences and that the banana hack is a more refined racket than a gundo hack which does make sense given that hack still uses the muffler to some degree, but I have a gundo 1.5" and find it suitably sporting and interesting, but not obnoxiously loud at all.
I read a lot of posts on various forums and I came away thinking that the gundo range that would please most people was a 1.5-1.75" bypass (2" if you like loud) and that the same could be said of a banana hack at 2-2.5."
infrasilver
Moderator
- Joined
- 4 Oct 2010
- Messages
- 9,934
That's correct, the nipple/banana bypass has the larger diameter pipe. All the info is in GT4's FAQ about the subject.
Lizard King
New member
- Joined
- 14 Oct 2014
- Messages
- 28
Who welded that?
Similar threads
New Threads
-
-
-
-
De-badging & re-badging Porsche script- Started by Maxie
- Replies: 1
-
-
-
Porsche Model Range
Porsche 911
Porsche 992: 2018-
Porsche 991: 2011-2019
Porsche 997: 2004-2012
Porsche 996: 1997-2005
Porsche 993: 1993-1998
Porsche 964: 1989-1993
Porsche Carrera 3.2: 1983-1989
Porsche Carrera SC: 1977-1983
Porsche 930 Turbo: 1975-1989
Porsche Early 911: 1964-1977
Porsche Hypercars
Porsche 918 Spyder
Porsche Carrera GT
Porsche GT1
Porsche 959
Other Current Porsche Model
Porsche Taycan : (2019-0%)
Porsche Macan : 2013-
Porsche Panamera : 2009-
Porsche Cayman: 2005-
Porsche Cayenne: 2003-
Porsche Boxster: 1997-
Porsche Legacy Models
Porsche 928
Porsche 968
Porsche 944
Porsche 924
Porsche 914
Porsche 912
Porsche 904
Porsche 550
Porsche 356 Speedster
Porsche 356
