Noise levels

[Speedy Se7en]

I have a standard 1.6K with standard road exhaust. Does any one know what noise level this is likely to produce. I would like to do a track day at Goodwood which is 98db. I would have thought most Caterhams would have failed this. Is there a temporary way of increasing the effectivness of the silencer.

[paulyb]

You may have a problem with the static noise test, but if you tell them your maximum revs are 6200, they will test you at about 4500 and you should be under 98dB

If you have any problems you could use a SuperTrap - they have them there to hire (£20/day)

I took my SLR there a couple of weeks ago, with a Supertrap at 4500 revs I was bang on 98dBs

Loads of other Caterhams there and no-one had problems with noise.

If you need a SuperTrap you may loose a small amount of top-end power (about 5BHP on mine)

[danwhiley]

I tested my 1.6K at Castle Combe a couple of weeks back and weighed in at 97.4dB. They wanted 4,500 rpm on the clock when testing (I think I might have been nearer 5,000 - I'm not very good with the pedal half-way down).

 

So, might be a bit tight, but you should be OK...

 

 

Dan.

[andytommo]

What is this supertrap thing? Sounds klike relief from my noisy exhaust for long trips?

 

Andy

[rgrigsby]

A Supertrap is a plug in device that fits over the end of the exhaust and reduces noise levels, BUT it also has a very noticeable effect on the way the engine runs in terms of power and driveability.

 

I used something similar at Goodwood last month, on my crossflow with it fitted the engine didn't really want to rev past around 6000 were as it normally goes to 7200 all too easily!! in terms of power loss I was about 8-10mph slower at the end of lavant straight with the muffler/supertrap device fitted.

 

There's also been the odd comment about how it's possible they could cause engine damage in some extreme cases. Although I'm not sure of the exact details. I didn't have any problems with the one I tried although I only used it for about 1-1.5hrs.

 

Cheers

 

Rob G

www.SpeedySeven.com

[paulyb]

I wouldn't recommend using it for long motorway journeys as the noise it makes is slightly quieter but sounds awful.

I didn't notice any difference in terms of revving but did certainly notice a loss of top-end power.

Not sure about effects on reliability but I guess it must increase back-pressure somewhat.

[Red SLR]

My SL1600 on TBs is 101dBm on std exhaust.

 

X777CAT

[Ian B]

On the subject of noise measurement, I have a digital Sound Level meter but does anyone know if the measurement is taken with A or C weighting?

I am making a bracket (0.5m and 45deg from the mouth of the exhaust) to more reliably make test measurements, anything else to consider?

 

MI 5EVN

[Pete]

According to the Blue Book the weighting should be 'A'. I don't know if that is the standard used at Goodwood which is probably more related to the speed at which Mrs Jones in the local housing estate can 'phone the Council to complain................