KR500 to silence it, at any price. How? (photo and video now added)

[anthony1956]

oh dear, silly me, I am thinking that the pistonheads exhaust is just that, the rear exit section and not the whole thing... I have asked for some pics so hopefully we will see. Literally.

 

Anthony

 

[tbird]

Didnt ask but what size is the raceco you have got fitted, I had a 5" CC can on the CSR and it was silly loud, as the car is mostly for touring with SWMBO I had a 7" can made by a local exhaust specialist and now its like a little mouse when cruising and not very loud under hard acceleration. Have you done everything you can with the setup you already have,

maybe worth having a conversation with Hayward and Scott to see if they could make a bung that would fit

Haward and Scott obviously the one in the pic would not fit but they might have some other design ideas

 

Dont think Dynatech vortex cones go small enough to help

 

Tim

 

[anthony1956]

um. mm. don't know. and car is not here just now. the raceco was fitted by me because of trhe excessive heat burning everyone, including me .. an dit is much quieter than the original.

 

I am wondering about repacking it. .. etc

 

this evening I am particularly unhappy because as far as I can see they should absolutely NOT be doing these tests because I have exemption from them.

 

edit: I now understand that it is the difference between compliance with car limits and general noise limits. As to the emissions, don't know yet.

 

Considering who to follow this up with and via... I am very resistant to being argumentative with them. edit: visited customs who suggested get my garagist to intercede (which they did and is where all the edit info is coming from)

 

Not a clue if further possibilities with existing setup; that's what my op was really about, if not entirely clear about it.

 

 

Anthony

 

 

Edited by - anthonym on 23 Jan 2011 17:18:37

[anthony1956]

exhaust bung: that's a clever idea.

 

Stainless Steel Exhaust Bung - Internal size of tailpipe needed. Reduces noise by up to 6db

 

Anthony

 

[Jason Plato]

and don't forget the old diesel mot test for visible smoke trick

 

use a throttle stop that only permits 1/3 throttle

 

it will still be fast ....

 

here is my Duratec R .... C7 TOP

Taffia joint AO with Al

 

[anthony1956]

where's the throttle stop?

 

Anthony

 

[rj]

The rear exit exhaust linked to is just the rear box. It won't fit directly on your current setup - nor on the std. R500 side exit box.

 

You are of course welcome to borrow my rear exit system for the test, but I doubt it's enough.

 

 

[Jason Plato]

you will have to make one

 

here is my Duratec R .... C7 TOP

Taffia joint AO with Al

 

[CageyH]

It's on the first page

 

Only dead fish go with the flow....!

[anthony1956]

tomorrow I'm going to see if I can't get someone (such as the RAC equivalent) to help me change some minds.

 

Anthony

 

[anthony1956]

throttle stop - on page 1 - I like that :-)

 

Anthony

 

[u01rsb]

On my stack dash you can select how many cylinders the engine has. This directly impacts how many revs are shown on the dash.

 

Theoretically you could have the dash showing 5000 rpm when the engine was actualy reving at 2500 if you got it wrong.

 

If the stack dash was bought directly from Caterham I don't think you can alter this parameter although if you send it to stack they can remove the lock on it.

 

Just a suggestion.

 

Rob

[anthony1956]

right then, an update.

 

Long story short (visited customs twice, mot centre (SCN) once, garage three times)

 

The special clearance I have allows breach of the vehicular standard of 73db but not the country everything included noise limit of 110db. (I did not dare ask about different types of db today)

 

My car recorded 118 or 107 db depending on who is asked at 6,500 rpm (with me at the throttle so... not sure how accurate that was)

 

On the face of it I have to lose 8 db - and then some to be confident.

 

One mechanic was blithely saying we can change the injection system and the exhaust system.. (so it would no longer be what it is). Changing to a rear exist double silencer exhaust I may be able to live with. Losing the throttle bodies, not so much.

 

Do I recall that an air box reduces noise? When can I get one cheap? I recall they cost silly money.

 

Repacking the Raceco exhaust comes top of the list and wonder whether one of those stainless steel bungs mentioned above could be employed? In fact it' still 5pm over there. Off to make a call, back soon.

 

All in all much happier that this can be done without breaking my bank.

 

Anthony

 

 

Edited by - anthonym on 21 Jan 2011 17:02:59

[anthony1956]

Hayward & Scott open til 5 Mon to Thu, 4pm on Fri and 1pm Sat.

 

By post:

Units 10 & 11 Nobel Square

Burnt Mills Industrial Estate

Basildon

Essex

SS13 1LS

 

Tel 0044 1268 727256

 

So maybe the morrow we'll see.

 

Not sure how it works with Raceco. Anyone?

 

Now going to search on airbox in blatchat for sound advice (pun intended)

first off, does it make much difference.

 

What I left out from the above was that this time it was "my" garagist who went to see the test people armed with my docs and came back with the story above.

 

Anthony

 

 

 

 

Edited by - anthonym on 21 Jan 2011 17:11:58

[anthony1956]

Decibel (Loudness) Comparison Chart

 

Here are some interesting numbers, collected from a variety of sources, that help one to understand the volume levels of various sources and how they can affect our hearing.

 

Environmental Noise

0dB Weakest sound heard

30dB Whisper Quiet Library

60-70dB Normal conversation (3-5')

 

this makes the 73db mentioned earlier seem wrong, or at least a different scale.

 

80dB Telephone dial tone

85dB City Traffic (inside car)

90dB Train whistle at 500', Truck Traffic

95dB Subway train at 200'

 

90 - 95dB Level at which sustained exposure may result in hearing loss

 

107dB Power mower at 3'

100dB Snowmobile, Motorcycle

110dB Power saw at 3'

115dB Sandblasting, Loud Rock Concert

 

118db report of my R500 at 6500 rpm (stationary) . Anyone else?

 

125dB Pain begins

125dB Pneumatic riveter at 4'

 

Even short term exposure can cause permanent damage - Loudest recommended exposure

 

140dB WITH hearing protection

140dB Jet engine at 100', Gun Blast

180dB Death of hearing tissue

194dB Loudest sound possible

 

here's the link:

http://www.gcaudio.com/resources/howtos/loudness.html

 

Anthony

 

 

Edited by - anthonym on 21 Jan 2011 17:57:32

[anthony1956]

Previously had about 101dB (with the standard 5" Caterham job) which makes sense as that's the SVA limit and the car's only been on the road 9 months.

 

does the above mean my R500 would have to have been 101db or less at its SVA? At what rpm?

 

Anthony

 

[anthony1956]

btt

 

does the above mean my R500 would have to have been 101db or less at its SVA? At what rpm?

 

Anthony

 

[anthony1956]

looks like the target is 107db and test was 118db at 6500rpm. Given sound doubles every 3db, seems to me they have to have included the backfires at 6500 rpm.

 

Anthony

 

[YvanR500]

Hi Anthony,

 

I have a Kr500 with a big titanium side exhaust and the rear under panel can.

I send you in few days some pics.

I have the same test (noise level) to pass for french registration.

You must buy a carbon intake system form reveries (not cheap 😬)

You must use too an under engine panel, and a lot of insulation.

 

Do you speak french, it's more easier for me

Please, give me your email for pics.

 

 

[anthony1956]

French is ok, where are you?

[CageyH]

Also interested in the measures required, as when I bring my car over permanently, I have to go through the UTAC as well.

[anthony1956]

for the record the moving noise test results were 95 DB as compared to the required 75db. So about 7 times the level needed.

 

where can I get a cheap airbox?

 

will airbox/rear exit double silenced can / under engine panel actually work? What additional insulation is Yvan talking about? Yvan?

 

Point of interest: police roadside static noise tests are base don exhaust exit only, so any lack of airbox or insulation or under panel will at that point, if rear exit exhuats remains fitted, make no difference, as far as I can see.

 

The static noise level is meausred after passing the moving noise test and is measure only at the exhaust exit (about 1 meter or something from it.

 

 

 

[CageyH]

He will probably be over here

[CageyH]

Or here

[anthony1956]

he's here:

 

http://sevener.fr/viewtopic.php?f=21&t=9471&p=171650&hilit=r500#p171650

 

I get the impression its work to do rather than work done and the car already has an airbox fitted in the pics. Anyway we are emailing, I'll ask. How's your French? I can cope but by no means fluent.