Noise reduction?
Discussion
OK - so Brunters is looming and I have to pass the 97dB limit.
So far it's passed the 105dB at Brands Indy, and then the 101 at Brands GP.
Standing behind it listening to idle, it is amazing just how much of the noise is coming from engine/box mechanicals rather than the pipes.
So, are there any fixes that people have tried on the tale pipes that have ever worked?
Pete
So far it's passed the 105dB at Brands Indy, and then the 101 at Brands GP.
Standing behind it listening to idle, it is amazing just how much of the noise is coming from engine/box mechanicals rather than the pipes.
So, are there any fixes that people have tried on the tale pipes that have ever worked?
Pete
Hi Pete
this answer will be a bit vague .................. but
there was a thread quite a while back about this could be 18 months/2 years ago. there are some reverse cones that fit in side the tail pipes that reduce noise, they are removable. i guess as well as cutting noise it will also cut power. for a more permanant aid there is the cross over pipe between silencers, Phil (pb3) has done this. just been having a read of Phils build site and it looks like he may be the man to contact, looks like he did quite a bit of research into the noise reduction.
Also, 2.0 litre duratec engines are quiet
dave
this answer will be a bit vague .................. but
there was a thread quite a while back about this could be 18 months/2 years ago. there are some reverse cones that fit in side the tail pipes that reduce noise, they are removable. i guess as well as cutting noise it will also cut power. for a more permanant aid there is the cross over pipe between silencers, Phil (pb3) has done this. just been having a read of Phils build site and it looks like he may be the man to contact, looks like he did quite a bit of research into the noise reduction.
Also, 2.0 litre duratec engines are quiet
dave
Cross over pipes.
Repackable silencers.
I think someone tried the cones and cooked the rear clip due to the back pressure increasing engine bay temp.
Or
A sheet of plywood with holes cut for the pipes. Stand it behind the car to eliminate engine and box mechanical noise during the test.
Steve
Repackable silencers.
I think someone tried the cones and cooked the rear clip due to the back pressure increasing engine bay temp.
Or
A sheet of plywood with holes cut for the pipes. Stand it behind the car to eliminate engine and box mechanical noise during the test.
Steve
Steve_D said:
I think someone tried the cones and cooked the rear clip due to the back pressure increasing engine bay temp.
Steve
Yep, that'll be the one I bought, have the spare clip though, just wondering how to modify it.Steve
On a seperate note, I was down the pub last night and someone was asking about my car, what it was etc. When I told them they immediately got their mobile out and showed me a picture of Luckys car parked outside Brians place in Wooburn Green, small world huh?
Where does one get reverse cones from?
The Ult is a funny thing. Much noisier static tham at speed wher the beatiful low growl fills the air. At tracks I've been to it soungd far less offensive in drive bys than even Caterhams that make a 97dB static with ease.
Like the grill cover idea. lots of noise polution through there.
The Ult is a funny thing. Much noisier static tham at speed wher the beatiful low growl fills the air. At tracks I've been to it soungd far less offensive in drive bys than even Caterhams that make a 97dB static with ease.
Like the grill cover idea. lots of noise polution through there.
SplatSpeed said:
passing the static test
try a cylinder mesh then an end cap
this should increase the distance from the exhaust therefore decreasing noise
i have a DB meter
sean
This does work! the meter will get confused as the noise is now going all over the place rather than straight into the meter. Drive-by may still be an issue... I have seen/got 3db drops with this...Some building steel mesh, and half of a baked bean can on the end, then clamp on to tail pipe, and it costs about £2 to make. Also, say your car revs at 5,500-6000 max. This should help a bit.try a cylinder mesh then an end cap
this should increase the distance from the exhaust therefore decreasing noise
i have a DB meter
sean
Edited by SplatSpeed on Wednesday 27th June 12:44
I have tried a couple of things to reduce exhaust noise. As Dave stated I put in a balance pipe and also made my silencers repackable.
I have had some success, repacking probably being the most effective but only when you find the original material has burnt/blown away. The balance pipe did not make a significant difference and I guess because the two tail pipes are so close it did not make any notable differnce to the overall sound (not as it would with say a Cobra with twin side pipes!).
After buying a sound meter and measuring the exhaust noise, then moving it around the engine bay it became apparent that a lot of the noise does come from the engine, in my case the solid roller lifters. Lifting up the rear clip and putting the meter near to the exhaust header I can get something like 112dB, this drops quite a lot with the clip closed and the meter held near the rear of the door. Therefore I came to the conclusion that I might have to change to hydraulic lifters but you never know if that alone would do it.
If the engine bay was fully lined with sound deadening material and the grills covered we may stand more of a chance.
When I did Cadwell recently I made a cardboard panel to put over the rear grill, I also repacked the silencers and made some baffle plates to attach to the tail pipes. Fortunately I did not need the cardboard or baffle plates, I just told them that my rev limit was 5000rpm! I was then asked to rev to 3000 (which I promptly replied 'arh, ok') and the car passed at 101dB (limit was 105dB).
I have never had a problem on drive by, as many have observed the car is one of the quieter ones out there under load. Why oh why do we have to have a static, totally unrealistic test I will never know!
I have had some success, repacking probably being the most effective but only when you find the original material has burnt/blown away. The balance pipe did not make a significant difference and I guess because the two tail pipes are so close it did not make any notable differnce to the overall sound (not as it would with say a Cobra with twin side pipes!).
After buying a sound meter and measuring the exhaust noise, then moving it around the engine bay it became apparent that a lot of the noise does come from the engine, in my case the solid roller lifters. Lifting up the rear clip and putting the meter near to the exhaust header I can get something like 112dB, this drops quite a lot with the clip closed and the meter held near the rear of the door. Therefore I came to the conclusion that I might have to change to hydraulic lifters but you never know if that alone would do it.
If the engine bay was fully lined with sound deadening material and the grills covered we may stand more of a chance.
When I did Cadwell recently I made a cardboard panel to put over the rear grill, I also repacked the silencers and made some baffle plates to attach to the tail pipes. Fortunately I did not need the cardboard or baffle plates, I just told them that my rev limit was 5000rpm! I was then asked to rev to 3000 (which I promptly replied 'arh, ok') and the car passed at 101dB (limit was 105dB).
I have never had a problem on drive by, as many have observed the car is one of the quieter ones out there under load. Why oh why do we have to have a static, totally unrealistic test I will never know!
Edited by Pb3 on Wednesday 27th June 14:09
I think there may be some confusion surrounding these 'cones' that folk have mentioned. I have a pair of these perforated cones just past the collector on each bank in my system. The idea is that they re-arrange the sound waves and thus make it quieter. The things that Simon is talking about are called Supertraps and basically fit on the end of the exhaust and are adjustable by way of fitting extra discs to create more back pressure and thus reduce the severity of noise.
I have not run my engine without the cones and so can give no indication of how much difference they would or would not make but they create little or no back pressure due to the shape having more surface area/holes than just a flat plate with holes in it.
As for the Supertraps, I would not bother personally as the only good back pressure is no back pressure and you don't want any more problems with your motor now do you P?
I have not run my engine without the cones and so can give no indication of how much difference they would or would not make but they create little or no back pressure due to the shape having more surface area/holes than just a flat plate with holes in it.
As for the Supertraps, I would not bother personally as the only good back pressure is no back pressure and you don't want any more problems with your motor now do you P?
I made enquiries regarding these cone things, from a USA company. What I wanted to know is what sort of noise reduction could I expect. To be fair the answer was a little vague, as is the question, but the answer I got back was something in the order of 2 to 3dB. That is not much when I was measured (static) as 104.5dB at Elvington.
You can get other types such as these internal disc types, see http://www.carchemistry.com/shop/index.php?action=... but they are probably more restrictive than the cones. Also Demon Tweeks do inserts but with both these types I think you will struggle to fit them as recommended due to the shortness of our systems.
You can get other types such as these internal disc types, see http://www.carchemistry.com/shop/index.php?action=... but they are probably more restrictive than the cones. Also Demon Tweeks do inserts but with both these types I think you will struggle to fit them as recommended due to the shortness of our systems.
SimonMaidenhead said:
LuckyP said:
Where does one get reverse cones from?
I've got some if you want them Pete, just be warned of the overheating consequences. I think Wayne was there when the unfortunate mishap occured, maybe have a word with him?Edited by SimonMaidenhead on Wednesday 27th June 13:50
Hi from across the pond. Laguna Seca over here has 90 and 92db days for track events so we have gotten pretty good at getting cars quiet.
I ended up switching mufflers to a 2.5" magnaflow. It reads 96db. It produced more power to boot. Since we are 90 and 92db limits, I added a set of supertrapps to the end. (These rob HP) The supertrapps with 12 disks, they can be tuned with # of disks, dropped the car to 86db.
I ended up switching mufflers to a 2.5" magnaflow. It reads 96db. It produced more power to boot. Since we are 90 and 92db limits, I added a set of supertrapps to the end. (These rob HP) The supertrapps with 12 disks, they can be tuned with # of disks, dropped the car to 86db.
shithotfast said:
SimonMaidenhead said:
LuckyP said:
Where does one get reverse cones from?
I've got some if you want them Pete, just be warned of the overheating consequences. I think Wayne was there when the unfortunate mishap occured, maybe have a word with him?Edited by SimonMaidenhead on Wednesday 27th June 13:50
shithotfast said:
shithotfast said:
SimonMaidenhead said:
LuckyP said:
Where does one get reverse cones from?
I've got some if you want them Pete, just be warned of the overheating consequences. I think Wayne was there when the unfortunate mishap occured, maybe have a word with him?Edited by SimonMaidenhead on Wednesday 27th June 13:50
SimonMaidenhead said:
On a seperate note, I was down the pub last night and someone was asking about my car, what it was etc. When I told them they immediately got their mobile out and showed me a picture of Luckys car parked outside Brians place in Wooburn Green, small world huh?
Who's Brian......and more to the point, who's been driving my car!!??Not me. Sure it wasn't Guy?
Lucky
Edited by LuckyP on Wednesday 27th June 18:41
Lucky
Not only do they do a static noise test at brunters but also have two noise meters strategically placed that can cause problems- you may well have to back off in these two places. As I mentioned before Gman's car upset them last time. The owners are very friendly and totally car mad but it is their business and so have to be strict about the noise limits. That is why I am not taking the ultima
Not only do they do a static noise test at brunters but also have two noise meters strategically placed that can cause problems- you may well have to back off in these two places. As I mentioned before Gman's car upset them last time. The owners are very friendly and totally car mad but it is their business and so have to be strict about the noise limits. That is why I am not taking the ultima
LuckyP said:
SimonMaidenhead said:
On a seperate note, I was down the pub last night and someone was asking about my car, what it was etc. When I told them they immediately got their mobile out and showed me a picture of Luckys car parked outside Brians place in Wooburn Green, small world huh?
Who's Brian......and more to the point, who's been driving my car!!??Not me. Sure it wasn't Guy?
Lucky
Edited by LuckyP on Wednesday 27th June 18:41
Could have been Guys' though, can't remember if Guys had a spoiler or not
Edited by SimonMaidenhead on Wednesday 27th June 18:55
Something else to try - http://www.hyperflow.com.au/techbulletins/Active_Exhaust_System.pdf
How about having a complete silencer box made with twin inlets that fit over the existing tail pipes. The internals could be made to act as a cross-over and would provide the pipe length required to adequately silence.
The whole thing would be held in place with spring clips as most race exhausts are.
Steve
The whole thing would be held in place with spring clips as most race exhausts are.
Steve
Gassing Station | Ultima | Top of Page | What's New | My Stuff