My RS is too loud - exhaust advice needed...
11-05-2006, 04:49 AM
#1
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My RS is too loud - exhaust advice needed...
I went to Castle Combe yesterday to watch the PCGB trackday. While I was there I took the opportunity to get the car noise tested - it was 108dB from the left hand exhaust, they didn't check the right but I guess it would be just as loud or louder! The limit at Castle Combe is 100dB (105dB on a noisy day). They told me my RS wouldn't even be allowed on track on a race day. 
The exhaust has been modified as follows... Cargraphic stainless rear silencer box (twin outlets - one each side), G-pipe to replace the small silencer under right hand wing, cat by-pass. And also undertray removed, and drilled airbox which must add to the noise.
It sounds wonderful - but if I'm ever going to get it on track in the UK I'll need to compromise and lose some of the noise.
Some people at the track were using 'end silencers' (big black cans bolted to the exhaust tips) which lose 'up to' 7 -9 dB. I'm not sure these would bring the noise down enough (but would be great if they did). Do these effect the engine in any way?
I have the original RS rear silencer (the long laterally mounted one) and the small side silencer box - and also the original bumper corner without the extra exhaust outlet moulding. The engine undertray is also removed but available to be put back on if it might help. I don't have a catalytic converter to replace the by-pass.
Has anyone here any experience of this problem? Would just fitting the side silencer and keeping the cargraphic backbox bring the noise down to allowable levels?
Finally, what does the standard RS system sound like?? I don't want to lose all of the noise!
Thanks for any advice and sorry for the long post,
Rich
The exhaust has been modified as follows... Cargraphic stainless rear silencer box (twin outlets - one each side), G-pipe to replace the small silencer under right hand wing, cat by-pass. And also undertray removed, and drilled airbox which must add to the noise.
It sounds wonderful - but if I'm ever going to get it on track in the UK I'll need to compromise and lose some of the noise.
Some people at the track were using 'end silencers' (big black cans bolted to the exhaust tips) which lose 'up to' 7 -9 dB. I'm not sure these would bring the noise down enough (but would be great if they did). Do these effect the engine in any way?
I have the original RS rear silencer (the long laterally mounted one) and the small side silencer box - and also the original bumper corner without the extra exhaust outlet moulding. The engine undertray is also removed but available to be put back on if it might help. I don't have a catalytic converter to replace the by-pass.
Has anyone here any experience of this problem? Would just fitting the side silencer and keeping the cargraphic backbox bring the noise down to allowable levels?
Finally, what does the standard RS system sound like?? I don't want to lose all of the noise!
Thanks for any advice and sorry for the long post,
Rich
Last edited by RSGulp; 11-05-2006 at 09:25 AM.
11-05-2006, 08:23 AM
#3
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If you just put the secondary muffler back on it should quiet things considerably. It's also easy enough that you could install it for track days and then take it back off when you're done at the track.
c
c
11-05-2006, 09:34 AM
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Noise rules S__ck! I suppose I am "Old School", but I thought Race cars were supposed to be noisy. I drove a CUP car yesterday while attending the "Jeff Gordon Driving Experience" at the Atlanta Motor Speedway and I must say, those cars are loud. But back to the point, I have a full Fabspeed setup and I barely meet the dB limit at the track on DE day. I hope you get you issues resolved. I wish I had a solution to offer you...have you contacted the manufacturer for suggestions?
11-05-2006, 10:37 AM
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Rich
It is a real problem and one I am suffering from as well. My de-cat, cup pipe and drilled filter box produces 105db at 4250rpm. Having learnt that, when they ask me for 3/4 revs, I cheat!!!
I wouldn't put a bomb type silencer on because they can really screw the car up. I haven't personally suffered, but have heard many bad tales. They could, of course, be urban myths, but why risk it.
One of the UK Rennlisters has ordered a back box from H&S and is going to test the noise and power levels with that. It coulod be an answer. Otherw ise, it seems that you need to go back to a 2 box approach.
It is a real problem and one I am suffering from as well. My de-cat, cup pipe and drilled filter box produces 105db at 4250rpm. Having learnt that, when they ask me for 3/4 revs, I cheat!!!
I wouldn't put a bomb type silencer on because they can really screw the car up. I haven't personally suffered, but have heard many bad tales. They could, of course, be urban myths, but why risk it.
One of the UK Rennlisters has ordered a back box from H&S and is going to test the noise and power levels with that. It coulod be an answer. Otherw ise, it seems that you need to go back to a 2 box approach.
11-05-2006, 10:42 AM
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Mine is already fairly loud with a B&B exhaust on it... But I'd like to add the crowning touch with a cat bypass. If you want to get rid of yours... name the price.
Last edited by Smokin; 11-05-2006 at 11:24 AM.
11-05-2006, 11:00 AM
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Rich, only 108db, great I still hold the record for a 964 at Castle Coombe of 108.5db 
with a 9m Cat bypass, Cargraphics Cup pipe and Ruf tail pipes.
The problem is that in standard form the 964 produced 98db, therefore your choices are limited. Replacing the G-Pipe with a Cup pipe is one way to go, however you will only be allowed on noisy days. You could revert back to fully standard, however you will lose some of that noise - which to me was something I was not prepared to do. Especially on the day I was there I saw a bloke stuff his 996GT3 RS into the barrier. Tears before bedtime
and therefore another reason not to do track days at CC.
There were some folks including a 993RS how were running additional silencers (tins cans) off their exhaust - looked horrible, however it did not seem to worry them - and they were allowed on the track - might be worth investigating.
Another alternative would not be to track days at CC and stick to less strict venues like Silverstone where noise does not seem to be an issue. Thuxton is another to avoid.
Hope this helps
Andy
with a 9m Cat bypass, Cargraphics Cup pipe and Ruf tail pipes.The problem is that in standard form the 964 produced 98db, therefore your choices are limited. Replacing the G-Pipe with a Cup pipe is one way to go, however you will only be allowed on noisy days. You could revert back to fully standard, however you will lose some of that noise - which to me was something I was not prepared to do. Especially on the day I was there I saw a bloke stuff his 996GT3 RS into the barrier. Tears before bedtime
and therefore another reason not to do track days at CC.There were some folks including a 993RS how were running additional silencers (tins cans) off their exhaust - looked horrible, however it did not seem to worry them - and they were allowed on the track - might be worth investigating.
Another alternative would not be to track days at CC and stick to less strict venues like Silverstone where noise does not seem to be an issue. Thuxton is another to avoid.
Hope this helps
Andy
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11-05-2006, 11:38 AM
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Andy - I didn't know there was a competition 
- the readout on their meter they showed me was actually 108.9 but I'm sure I went a little over 4,500rpm which is where they were taking the measurement. I guess your title is safe for now! 
My mother lives in Durrington village near Salisbury - maybe I should pop by next time I'm near and we could have a sound-off?!
SimonEx - Unfortunately there isn't really any way of cheating the system at CC either - one guy watches the rev counter as you increase revs, then indicates to the guy to take the reading at exactly 4,500rpm.
Looking more closely at my exhaust set-up - the cat bypass enters the backbox silencer at the left side, the backbox then has two exits (one each side). The left comes out right next to where the 'cat pipe' goes in and exits directly to the left tailpipe. The right exits straight to the g-pipe and then through the right tail pipe.
Simply putting the secondary silencer back on I think will only reduce noise from the right hand tailpipe.
Here's an idea...
If I was to put the secondary silencer back on that might take care of the noise from r/h tailpipe. I could also put the undertray back on for trackdays to reduce engine noise.
Would it be an option, just for trackdays, to remove the l/hand tailpipe where it exits the backbox then cap the exit? Or will that damage the engine? (I notice fabspeed do a twin outlet rear silencer where there is the option to fit only one tailpipe and cap the spare hole, or fit both tailpipes.
I'm not sure what goes on inside the backbox - whether the exhaust gasses are 'balanced' to both exits or whether capping one would just force the gasses out of the other, and therefore through the secondary silencer. Maybe this is the way to go - or it might damage the engine??
- the readout on their meter they showed me was actually 108.9 but I'm sure I went a little over 4,500rpm which is where they were taking the measurement. I guess your title is safe for now! My mother lives in Durrington village near Salisbury - maybe I should pop by next time I'm near and we could have a sound-off?!
SimonEx - Unfortunately there isn't really any way of cheating the system at CC either - one guy watches the rev counter as you increase revs, then indicates to the guy to take the reading at exactly 4,500rpm.
Looking more closely at my exhaust set-up - the cat bypass enters the backbox silencer at the left side, the backbox then has two exits (one each side). The left comes out right next to where the 'cat pipe' goes in and exits directly to the left tailpipe. The right exits straight to the g-pipe and then through the right tail pipe.
Simply putting the secondary silencer back on I think will only reduce noise from the right hand tailpipe.
Here's an idea...
If I was to put the secondary silencer back on that might take care of the noise from r/h tailpipe. I could also put the undertray back on for trackdays to reduce engine noise.
Would it be an option, just for trackdays, to remove the l/hand tailpipe where it exits the backbox then cap the exit? Or will that damage the engine? (I notice fabspeed do a twin outlet rear silencer where there is the option to fit only one tailpipe and cap the spare hole, or fit both tailpipes.
I'm not sure what goes on inside the backbox - whether the exhaust gasses are 'balanced' to both exits or whether capping one would just force the gasses out of the other, and therefore through the secondary silencer. Maybe this is the way to go - or it might damage the engine??
Last edited by RSGulp; 11-05-2006 at 02:59 PM.
11-05-2006, 01:36 PM
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Rich -100 cell race cat, C2 primary silencer, secondary silencer, <105db......
Race cat, Cup pipe, secondary silencer >105db......with this (original) set up I had to wear ear plugs under my crash hat!!
I have one of those Tudor mortars to replace the tailpipe, but I doubt it's worth 2db......
I seems to be the Supertraps that present probs with too much back pressure.
Be good to see that old banger on track at last!!
Rgds
Mel
Race cat, Cup pipe, secondary silencer >105db......with this (original) set up I had to wear ear plugs under my crash hat!!
I have one of those Tudor mortars to replace the tailpipe, but I doubt it's worth 2db......
I seems to be the Supertraps that present probs with too much back pressure.
Be good to see that old banger on track at last!!
Rgds
Mel
11-05-2006, 04:30 PM
#11
Nordschleife Master
Our local track has an 89db limit and the cup cars with a cat bypass, primary bypass and the secondary muffler do not have any issues. Stock headers and stock intake/airbox.
11-05-2006, 04:56 PM
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Why don't you come to the meeting on Nov 26th at Worcester Park, London - see other post on this forum and we can do this sound off! It would be greta to meet/hear you.
Cheers,
David
Cheers,
David
11-05-2006, 11:42 PM
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Wow this is odd cause last time I did sound check (a month ago), I did 94.8 (10 or 15 feet away behind the car) and I run B&B headers, no cat and single B&B exhaust.
My car is loud but not illegal loud. Never got pulled over by cops and where I live, cops are **** with loud exhaust.
My car is loud but not illegal loud. Never got pulled over by cops and where I live, cops are **** with loud exhaust.
11-06-2006, 02:35 AM
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Cway27 - The general distance over here for noise tests is .5m away from the exhaust tip for static tests, drive by's at various points around certain tracks.
Rich, my set up on the C4 is a cat bypass, cup pipe and sec. silencer. Didn't have any issues at Donnington, but static was last measured at 103db on the static. Sounds liek stock is the only setup to have to get past a strict static test.
Rob
Rich, my set up on the C4 is a cat bypass, cup pipe and sec. silencer. Didn't have any issues at Donnington, but static was last measured at 103db on the static. Sounds liek stock is the only setup to have to get past a strict static test.
Rob
11-06-2006, 03:40 AM
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I think I'll put the secondary silencer and engine undertray back on, keeping the cargraphic 'straight through silencer' and cat bypass as is, and get is noise tested again. If I can get it through a 105dBA test at least I'll be able to get it on some tracks here in the UK.
I'm not sure the left exhaust will be affected by the secondary silencer though (still too loud). I'll email Cargraphic in Germany to ask if I can temporarily cap the left exit on their box.
I'm not sure the left exhaust will be affected by the secondary silencer though (still too loud). I'll email Cargraphic in Germany to ask if I can temporarily cap the left exit on their box.