noise levels and silencers

[rickability]

had my car noise tested at goodwood today.mmmmmmmmm 115 DB. Has anybody got information how to run these cars at 105db or below? thanks,Richard

[TuxMan]

Hi Richard ,we did alot of test last week at stoneleigh with some very high noise levels so we all have the same problem at the moment !!! repacking the system will help and i think some downwood facing pipe exits would also be a improvement !!!! But it would seem to be a problem we all have with no easy fix !! i wonder if the factory has any suggestions ???

[JSS 911]

Richard thanks for the ride , sounded great to me
John

[Rusti Evo]

Goodwood just let me thro on the 1st at 105db. Repacked silencers, max revs 5000 Sails thro the drive-by - miles under.

I've made up some Supertrapps and these appear to reduce by 3db. Am going to try some Merlins aimed down at 60 degrees.

Have just cancelled Track Masters, Castle Combe on 19th cos I don't see a hope of getting 100db at 4500 rpm

Stuart

[Boosted LS1]

Could you point the pipe exits towards eachother and would that help cancel out the noise? Might look naff but could be removable parts.

[Rusti Evo]

Boosted LS1 said:

Could you point the pipe exits towards eachother and would that help cancel out the noise? Might look naff but could be removable parts.

How about making vertical extensions a bit like a swamp buggy or old school chopper now that's really naff!!!!

Hmmmmmmmm, if the chimneys were tall enough the noise man couldn't reach them - there's justice

[Boosted LS1]

^Yeh, could work lol, may as well fit a wing on top. My thought was that the pipes would cancel each other out if facing eachother as this is often what happens in silencers.

[kylemrushall]

You can fit small silencers on the back of the tail pipes, i know a couple of TVR boys have done it with good results ie one went from 113db to 105db!! i believe they are around £80-£100 a pair custom made to fit our tail pipes. I did mention trying start an Ultima bulk buy but had absolutely no interest??? There would be a small loss in power. It is the way i will go when i want to do trackdays instead of spending £000s on new exhausts/modifications.

[gtr-gaz]

Don't forget that any add-on jobbies will also keep the heat in, as well as the sound.
I have heard of instances (well, one actually!), where the rear clip has almost melted due to the heat build up.

So, be careful what you use!!

[bluesatin]

And the clip melting was at Goodwood!

[Rusti Evo]

I didn't give the ACT one a go cos the outlet diameter is scary small. Also, don't see how you could fit it with the grill in the clip.
OK for a Chimaera but don't fancy my luck on a bellowing Ultima.

Going to put some proper effort into this problem as it's a personal challenge to get a GTR onto Goodwood on a 98db day ....

[bluesatin]

Just been speaking to Crazy of Cookham about this and perhaps the factory will come up with an option for this. I was thinking of a single silencer with cross over but keeping the same headers and outlets in the grill.I have had the car for 6 years and not sure how much silencing is left!

[Rusti Evo]

Just for interest when I opened up my 4 year old silencers there was only some very tatty remnants of steel wool and some bits of glass fibre cloth left. No wonder it sounded so good!

Repacked with Merlin silencer basalt (I reckon this is just ordinary rockwool), one trackday later there wasn't a wisp of packing left!!! Lovely sound though

Packed this time with ceramic cloth and e-glass woving, nice restrained sound track, how long will this last? ..........

[SimonMaidenhead]

bluesatin said:

And the clip melting was at Goodwood!

Still have the clip, not a pretty sight!!!

[Pb3]

The first time I repacked mine I used loft insulation, it turns to dust pretty quickly and gets blown out. Then I used some fibreglass stuff from Car Builder Solutions, that lasted longer but still burnt away. Now I use normal fibreglass matting, as direct by AK Sportscars, its cheap works and lasts longer!

[Steve_D]

SimonMaidenhead said:

......Still have the clip, not a pretty sight!!!

I know the feeling there.
It sits in the corner of the garden, no use to man or beast but cost so much to replace you can't make yourself throw it in the skip.

Steve

[rossins]

I'm currently trying to reduce my GTR from 104db to 95 to get through the static test at croft. Have spoken to a firm specialising in exhausts that are confident that re-packing the silences with a special sound deadening material that can withstand 1000c the problem will be sorted. Will keep you posted with the results - in about a month.

Simon

[rickability]

Thanks for the input guys.i'm gonna speak to hayward and scott about this to see what the long term solution could be.I tried a guess with extended pipe and supertrap to a 964rs i used to own.It ended up with the car not exhausting properly , loss of power and cherry red headers which resulted in a fire outside goodwood circuit.I kid you not that i had to extinguish the flames by removing clothing to douse it!!!! I think this is a proper engineering problem that needs to be solved by bearded blokes with calculators and pencils...All they will need is punters with money , i suspect......

[LuckyP]

Ted's got a beard. Not sure if he owns a calculator......but I'm sure he likes punters with money!!

I bet he could sell at least 25 'solutions'. Anyone asked him?

But hold on a mo. Is there really a problem? 8 track days last year, most 105dB days, of which there are plenty. All the testers were aware that a static Ultima proves much more of a problem than the deep rumble as they pass at speed. Have you heard a Superlegera at speed? Deafening!!

Lucks

[rickability]

i know what you mean pete.drive by is just about acceptable at some places, but if your engine has big mods and revs like a bike it then starts to get difficult.. just spoke to the factory and they say these silencers are pretty much straight through and that they dont supply anything else.nice.