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cvega
Monza


Joined: 25 Feb 2013
Posts: 157



PostPosted: Thu Sep 20, 2018 11:10 am    Post subject: muffler bypass vs MOT Reply with quote

Hi folks,

as i have to change my mufflers anyway (mine are rotting and making all kinds of rattly sounds) i'm considering either a Topgear exhaust OR just a porscheshop and/or fabspeed straight pipes out of cats. Anyone running a straight piped 996 in the UK? I've seen videos on youtube of folks from US and australia, but want to hear from someone here.

- noise - how's that gonna go down at MOT? i don't see a dB limit anywhere just "excessive noise" - sounds like the tester will have free hand there
- emissions - are they affected bymufflers? I'd guess no, but I don't really know?
_________________

2003 996 C2
2017 Leaf 30kWh
gone: 2010 335d, 2007 Cayman S, 2008 Civic Type-R, 1992 MR2 Turbo ,1994 MR2 N/A
 
  
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James M-S
Hockenheim


Joined: 11 Apr 2017
Posts: 680
Location: Derby

2009 Porsche 997 Carrera 2

PostPosted: Thu Sep 20, 2018 11:46 am    Post subject: Reply with quote

I think back boxes may affect emissions. (Although I can’t understand how)

A couple of years ago my 997 failed emissions on one side, the tester stuck the probe in the other side and passed it, told me he thought it was due to gases escaping either through the seam in the back box, or the join with the centre section.

I had the back boxes off for gundo, and couldn’t see anything on inspection.

Passed the next MoT so I’m not sure if it was the join or his probe was playing up.

Straight through pipes would fail on noise I imagine, so you’ll have to accept the chore of an annual pre-MoT swap.

Personally I would go with top gear. Straight through is obnoxiously loud in my opinion.

James
_________________
Manual 997.2 c2 :Basalt + gtechniq : H&S + Gundo

Last edited by James M-S on Thu Sep 20, 2018 11:50 am; edited 1 time in total
 
  
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James M-S
Hockenheim


Joined: 11 Apr 2017
Posts: 680
Location: Derby

2009 Porsche 997 Carrera 2

PostPosted: Thu Sep 20, 2018 11:47 am    Post subject: Reply with quote

Double post
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MrC986
Newbie


Joined: 16 Oct 2017
Posts: 12
Location: Staffordshire


PostPosted: Thu Sep 20, 2018 1:46 pm    Post subject: Reply with quote

I've run bypass pipes before and the first 996 wasn't an issue on the MOT emissions whereas the current one took a while to claw its way through on the CO readings - I suspect the engine temperature on my car for the latest test wasn't quite as hot as it could have been which wouldn't have helped. I've just fitted Topgear boxes and 200 cell cats (the bypass pipes will be sold). My bypass pipes werent that popular in the village I live in for non petrolhead neighbours as they make a considerable noise on cold start-up BTW, though mine is used as an occasional 2nd car.
 
  
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rabbitstew
Hockenheim


Joined: 21 Aug 2015
Posts: 637



PostPosted: Thu Sep 20, 2018 3:47 pm    Post subject: Reply with quote

I had a painfully loud exhaust on a Nissan 350z I had once. I measured it at 106db inside the cabin. On its MOT the tester just made an advisory that the exhaust was loud and passed it.

My Ducati 996 has a similar advisory sometimes with its open race pipes.

So based on that I dont think noise is something they can fail on, and it will be fine as long as the car passes the emissions test.
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1999 Yamaha R1
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kingston
Österreich


Joined: 09 Jun 2010
Posts: 958



PostPosted: Thu Sep 20, 2018 3:56 pm    Post subject: Reply with quote

ive run straight out from Cat in mine before (had a loop to mimic the route through the back boxes though).

Measured 105dB outside at track testing distance/conditions.

On the road it sounds awesome with pops/bangs/crackles etc, but it was robbed of some low down torque which was noticeable. Ended up asking Top Gear or one of them to make me an After Hours style exhaust which gave me back the torque and some pops.
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cvega
Monza


Joined: 25 Feb 2013
Posts: 157



PostPosted: Mon Sep 24, 2018 12:09 pm    Post subject: Reply with quote

kingston wrote:
ive run straight out from Cat in mine before (had a loop to mimic the route through the back boxes though).

Measured 105dB outside at track testing distance/conditions.

On the road it sounds awesome with pops/bangs/crackles etc, but it was robbed of some low down torque which was noticeable. Ended up asking Top Gear or one of them to make me an After Hours style exhaust which gave me back the torque and some pops.


Any pictures of that ?
_________________

2003 996 C2
2017 Leaf 30kWh
gone: 2010 335d, 2007 Cayman S, 2008 Civic Type-R, 1992 MR2 Turbo ,1994 MR2 N/A
 
  
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77szymon
Silverstone


Joined: 14 Mar 2018
Posts: 106
Location: UK

2003 Porsche 996 Carrera 4S

PostPosted: Sat Sep 29, 2018 10:50 pm    Post subject: Reply with quote

Hi,

I have £20 mod done at local exhaust repair shop, it is not as loud on start up and if driving slow you can live with it but under load noise is insane in good and bad way depends on your day I guess Laughing

BAD:
M62 J21 to J22 (uphill) 6th 70-80 MPH on top of the motorway your ears screaming why are you doing this to us Floor you can do it on 4th bit better but economy eh!

GOOD
Manchester night out all people screaming for rev, also on A roads experience is x2 with high revving as noise is so close to F1 mixed with V8 thumbsup and on motorways I use rev as a honk so far works 100% every time Mr. Green


So my kit is 2x 90 degrees pipes, unfortunately back tips will be with different angle but still looking nice forgot to take picture but:
Open Youtube Page



You will lose power as I can feel it so if you would like to do it more correct you should make it longer I think every repair shop should do it for you as it will be very easy job.

Some pictures:
_________________
2003 Porsche 911 996 c4s
1988 BMW 635csi Highline - waiting for full restoration
1999 BMW e36 328i Cabrio - still not finished project.....
2011 Mercedes S350L
2004 Audi a2 1.4 tdi - I can't stress enough how good these cars are
2012 Mercedes C220 cdi Estate AMG Sport Plus Pack - wife
 



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77szymon
Silverstone


Joined: 14 Mar 2018
Posts: 106
Location: UK

2003 Porsche 996 Carrera 4S

PostPosted: Sat Sep 29, 2018 10:57 pm    Post subject: Reply with quote

I just did small drawing like I was planning to do so Very Happy
_________________
2003 Porsche 911 996 c4s
1988 BMW 635csi Highline - waiting for full restoration
1999 BMW e36 328i Cabrio - still not finished project.....
2011 Mercedes S350L
2004 Audi a2 1.4 tdi - I can't stress enough how good these cars are
2012 Mercedes C220 cdi Estate AMG Sport Plus Pack - wife
 



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alex yates
Brands Hatch
Brands Hatch


Joined: 06 Mar 2014
Posts: 14285
Location: The Ribble Valley, Lancashire

2000 Porsche 996 Carrera 4

PostPosted: Sun Sep 30, 2018 7:20 am    Post subject: Reply with quote

Nothing has made me smile on our meets as much as following you home Szymon!! Thumb Grin
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cvega
Monza


Joined: 25 Feb 2013
Posts: 157



PostPosted: Mon Oct 15, 2018 8:51 am    Post subject: Reply with quote

I've made up my mind, I'm doing it.
I found those and the price seems about right (unlike the £500 fabspeed nonsense) https://www.porscheshop.co.uk/porsche-mechanical-parts/porsche-996-mechanical-parts-1998-to-2005/porsche-996-exhausts-1998-to-2005/eurocup-gt-porsche-996-carrera-2-4-gt3-silencer-by-pass-tail-pipes-1998-2002.html

Any coupons for porscheshop off this forum?
_________________

2003 996 C2
2017 Leaf 30kWh
gone: 2010 335d, 2007 Cayman S, 2008 Civic Type-R, 1992 MR2 Turbo ,1994 MR2 N/A
 
  
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MrC986
Newbie


Joined: 16 Oct 2017
Posts: 12
Location: Staffordshire


PostPosted: Mon Oct 15, 2018 9:02 am    Post subject: Reply with quote

I've sent you a PM
 
  
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Marky911
Kyalami


Joined: 04 Jun 2009
Posts: 1850



PostPosted: Mon Oct 15, 2018 10:06 am    Post subject: Reply with quote

Jesus!

If nothing else, this thread proves how different we all are. Grin
 
  
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cvega
Monza


Joined: 25 Feb 2013
Posts: 157



PostPosted: Mon Oct 15, 2018 10:28 am    Post subject: Reply with quote

Marky911 wrote:
Jesus!

If nothing else, this thread proves how different we all are. Grin


What do you mean ? Smile
_________________

2003 996 C2
2017 Leaf 30kWh
gone: 2010 335d, 2007 Cayman S, 2008 Civic Type-R, 1992 MR2 Turbo ,1994 MR2 N/A
 
  
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77szymon
Silverstone


Joined: 14 Mar 2018
Posts: 106
Location: UK

2003 Porsche 996 Carrera 4S

PostPosted: Mon Oct 15, 2018 10:53 am    Post subject: Reply with quote

OMG £ 148...…… I will take your boxes out and install mine pipes in this price this Friday...... Very Happy

I can give away my pipes as I'm back in muffler sound puh


PM if interested.
_________________
2003 Porsche 911 996 c4s
1988 BMW 635csi Highline - waiting for full restoration
1999 BMW e36 328i Cabrio - still not finished project.....
2011 Mercedes S350L
2004 Audi a2 1.4 tdi - I can't stress enough how good these cars are
2012 Mercedes C220 cdi Estate AMG Sport Plus Pack - wife
 
  
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kingston
Österreich


Joined: 09 Jun 2010
Posts: 958



PostPosted: Mon Oct 15, 2018 10:53 am    Post subject: Reply with quote

cvega wrote:
kingston wrote:
ive run straight out from Cat in mine before (had a loop to mimic the route through the back boxes though).

Measured 105dB outside at track testing distance/conditions.

On the road it sounds awesome with pops/bangs/crackles etc, but it was robbed of some low down torque which was noticeable. Ended up asking Top Gear or one of them to make me an After Hours style exhaust which gave me back the torque and some pops.


Any pictures of that ?


Ill try and find the pictures but im not sure where they are now. HEres a video for comparison;
https://www.youtube.com/watch?v=JOCPwHdS-5E&t=86s
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Marky911
Kyalami


Joined: 04 Jun 2009
Posts: 1850



PostPosted: Mon Oct 15, 2018 1:15 pm    Post subject: Reply with quote

Sorry cvega,nothing personal, I was just being grumpy as I think you're about to waste your money. The video Szymon posted just doesn't give the real volume of those delete pipe things.

They're stupidly loud, you lose the flat 6 noise at anything but banzai revs and on the overrun they sound like that noise you get when you pull the plug out of a bath or sink. You know that gurgly noise. And it sounds like a 1.6L Ford Sierra with a cherry bomb on it at tickover. Grin

They're just so god damn awful I'm truly baffled to the point of laughter, that anyone can think it sounds good.

No offence but save your money. Unless you've heard a car in person and definitely think you like the noise still.
They will sound a bit better on a 3.6 as everything does, but on a 3.4 they're just horrendous.
I don't know what you have by the way. Hopefully not a 3.4.

Like I say though, it highlights one man's symphony is another man's wet fart.
You pays your money, you takes your choice. Like I say, no offence.
Wink

And I hope Szymon is joking about putting mufflers back on his, as he's been raving about these delete pipes more than anyone on here. So I wouldn't expect such a legendary U-turn. Grin



ETA - I see you have a 3.6. Tiny saving grace, glimmer of hope, etc etc. Very Happy
 
  
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cvega
Monza


Joined: 25 Feb 2013
Posts: 157



PostPosted: Mon Oct 15, 2018 1:25 pm    Post subject: Reply with quote

haha I'm torn, I remember having a stupidly loud exhaust on my MR2 turbo and i managed to live with it for a week. I think it was a Blitz Nur spec.

Interestingly, the cost of the whole thing is similar, as you ideally need to remap the car with bypasses not to loose power.
_________________

2003 996 C2
2017 Leaf 30kWh
gone: 2010 335d, 2007 Cayman S, 2008 Civic Type-R, 1992 MR2 Turbo ,1994 MR2 N/A
 
  
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Marky911
Kyalami


Joined: 04 Jun 2009
Posts: 1850



PostPosted: Mon Oct 15, 2018 1:32 pm    Post subject: Reply with quote

Ha, yep been there, done it. As you get older you realise there's "Sound" and then there's "noise". Wink

I bought a huge exhaust for my MR2 Turbo back in the day, an HKS Hyper Medallion or some bonkers named thing like that. It was actually the same volume as stock when I started it up . Oh the disappointment on my little face. Grin

It's all so subjective, so best to listen to a car in person but that's not always possible. Thumb
 
  
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cvega
Monza


Joined: 25 Feb 2013
Posts: 157



PostPosted: Mon Oct 15, 2018 1:43 pm    Post subject: Reply with quote

hehe yep I went from the Blitz NUR spec to a HKS Silent HiPower something. Mad names indeed but exaust was so much more refined...
_________________

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2017 Leaf 30kWh
gone: 2010 335d, 2007 Cayman S, 2008 Civic Type-R, 1992 MR2 Turbo ,1994 MR2 N/A
 



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