Bought a BDR - now rapidly becoming deaf...

[beckerman]

Help!

Since procuring a rather lovely 1700 BDR a month or so ago I have covered about 1000 miles of country lane driving but am starting to suffer badly in the ear department. Apart from the first couple of times I took the car out, I've always worn ear plugs but the car still seems excessively loud and I am significantly concerned about long term exposure to such high levels. I'm getting some custom fit silicon plugs made in the next couple of weeks but has anyone got any recommendation on how to quieten the beast down to something approaching civility?

First stop would seem to be swapping out the rather tired silencer for something newer and better packed - any recommendations? Also, any ideas on how to lower the induction roar a little?

And before anyone makes any comments saying that i should learn to live with it, I know it's not scientific, but an iPhone DB meter registered 107db at ear level whilst cruising at 70........ I would like to be able to use the car for more than 10 minutes at a time without risking my hearing

Any help from the knowledgable masses very gratefully received!

/beckerman

[Murph7355]

Pardon?

[beckerman]

Edited by beckerman on Tuesday 27th April 23:35

[CatMatt7]

It might be worth having a look at a Raceco silencer - they are very good at making noisy cars quiet and can be repacked.

Might also be worth in investing in better ear plugs, possibly some that are specifically molded to your ears - alternatively you could try a crash helmet.

I agree that 107dB is too loud for prolonged use.

Good luck!

Matt

[Steve-B]

if you look on the other place (BC) you'll see there's a bulk buy on professional earplugs for a very nice price. if you don't have a login there you can click on the person doing its' icon and email them. i think the deal is still open, but am not 100% on that.

[Fat Arnie]

I notice Caterham never provided any warning regarding the damage a Seven could do to ones hearing. In these days of corporate responsibility is that not a little risky? My car has certainly effected my hearing.

[Dave J]

affeted more than your hearing Arnie

[V7SLR]

Arnie, wasn't it you alone who pressed the loud pedal!

[Fat Arnie]

A machine operator who removes a digit using an unguarded machine presses the "start" button, but at least he sould have been furnished with policy for machine operation.

How would someone buying a car know it was likely to damage their hearing?

It's an interesting thought in our ever more litigeous world.....

Edited by Fat Arnie on Wednesday 28th April 13:42

[V7SLR]

I'm certainly no expert, but I think you'll find that the SVA/IVA covers the aspects of noise etc for the purpose of motor vehicle liability, in the same way that the CE regulations/approvals cover the safety of other consumer goods such as washing machines, tools, etc.

Edited by V7SLR on Wednesday 28th April 14:13

[Fat Arnie]

So a pre SVA/IVA car????

[mickrick]

Ahem...I don't think your car was as it came out of Dartford Arnie.
In fact, I think your car damaged my eyes! Now where's the number of my Lawyer.....

[Fat Arnie]

My car was quiet after I sold the original exhaust to Roy Wood.

[Murph7355]

Fat Arnie said:

...
It's an interesting thought in our ever more litigeous world.....

No it's not - it's a thought that should never be uttered again in case some cretinous lawyer takes up the challenge.

[beckerman]

Thanks for the replies so far chaps, at least my question has stimulated some debate

I'll have a look at the Raceco silencer recommended - any other options out there? I've seen the name Techcraft mentioned on the other place as well I think - any good?. I take it that it would be prudent to go for the largest OD that'll fit?

Re. plugs, I nipped down to SpecSavers for a hearing check - strangely they have started doing ears as well as eyes - and am getting moulds made for some custom-fit silicone jobbies next week. Hopefully they should block out some of the wind whistle as well as induction roar but I'll let you know how they work out.

By the way, aside from wide-track suspension and an unleaded conversion, as far as I know the car is as it left the factory.

[Murph7355]

Is it exhaust noise that you're getting? Or wind noise? Induction roar?

Ear plugs is obviously a good option, but would be worth assessing the source of the noise fully first...

[Graham E]

Are you sure it's 107 dB? SPL meters measure sound pressure level. The pressure changes due to moving about in the wind at 70 will surely make the meter readings wildly innacurate? As a tester, put your meter on 60dB setting, and waft it in the air in a quiet room. On my meter, you'd hit the "+10" part of the vu meter pretty easily.

That aside, those repackable silencers are great, got our shouty K series round croft last year, which is quite hard now they're at 98dB at times.

[beckerman]

Murph7355 said:

Is it exhaust noise that you're getting? Or wind noise? Induction roar?

Ear plugs is obviously a good option, but would be worth assessing the source of the noise fully first...

Everything! It's a veritable cornucopia of aural sensation...

The induction roar is considerable when you open the throttle and, from what I've read seems to be a function of the short inlet manifold used for the 45s so I suppose can't be fixed without an airbox of some sort. Putting a longer inlet manifold on would probably mean that the bonnet wouldn't fit. The exhaust is also extremely boomy and sounds a little hollow when tapped so I thought that would be a good place to start...checking the history file it's probably done ~10k miles and is 12 years old........

Re. wind noise, my right ear does seem to coincide with the top rear of the door, which seems to be unavoidable if you're about 6', so will be right in the line of any shedding turbulent flow.....hunkering down in the seat doesn't seem to make any difference apart from making gear changes nigh on impossible.... Has anyone tried fitting one of the stretchy wind deflector thingies sold by SBFS that fits between the head rests? The normal squishy earplugs seem reasonably ok for a bit but don't do a great job of cutting out either the boom or the wind noise - putting a finger gently over the exposed end makes a great deal of difference to the high frequency stuff.

Noise levels. The iPhone App I used records both a peak and the instantaneous level. 107db was the peak but I'll admit I haven't as yet undertaken any sort of testing to check either the accuracy of the App or the repeatability of the level. To be honest, the indicated level seemed to confirm why my ears were hurting after a spirited drive and that was good enough for me at the time. Now I start thinking about reducing the level by changing bits on & off the car, I'm going to have to get a firm baseline reading to work from.

[jas xjr]

no idea about caterhams or 7's in general . but is it possible to re-route the exhaust?

[Tango7]

You could try an Autocom headset system and if you didn't want to use the bulkier ear defender headsets, there is a much neater option available if you search Blatchat. I have used these in a very noisy VX with a SCCR gearbox and it was a massive relief not only to listen to music or my phone in the car but also near silence when blatting along the motorway.