Has anyone had any experience with the BJ Acoustics sound deadening kits? £200 seems quite steep but if it helps to reduce the boom caused by the ScoobySport exhaust then it may be a good investment.

Any other ideas about reducing motorway boom?

 

The boom is largely through sound transmission, not resonance.

I put underlay in my boot (2 layers of the cheap shredded fibre stuff, not the rubbery stuff) and it really deadened the sound of my scoobysport back box.

I have also dynamatted quite a bit of the boot, so it may be a combination of the two, but I'd say that the underlay made most difference.

HTH,

Nick.

 

Drive on the A roads only??

Kits like BJ Acoustics or the application of other sound dampening material (dynamat/brownbread etc) will significantly reduce the noise levels in your car. Ive done the whole boot and under the rear seats for £90 worth of Brown Bread from Maplins - and its made a noticable difference.

You just buy the stuff, strip your carpets out and "patch" squares of the stuff onto the most noisy parts of the car (boot, rear wheel arches, front arches and floor of car, front doors) and it custs out resonance as the panels vibrate over the motorway surface (via tyres and suspension).

Its a days job, but worth it if you have the time

Jza

 

Nick - the boot is already dynamatted and I filled the spare wheel with foam last weekend. I will try the underlay this weekend and if that does not help then I guess I'll have to take the whole of the interior out and start applying patches of whatever to the floor, wheel arches and transmission tunnel...

 

I've got the same thing - SS backbox with that specially tuned drone that comes on at motorway speeds & nowhere else - and a fair bit of dynamat around the place as well which seems to sort most things out except for the backbox! I've put 2 layers of ordinary carpet underlay in the boot - it sort of helps, but not quite enough.
I've actually got the BJ Accoustics kit sitting on my kitchen floor at the moment waiting to go in at the weekend. I'll let you know what the difference is! I'm hoping for quite a bit so the backbox noise level can be controlled by those conveniently placed glass things in the back that go up & down

 

I'll be very interested to see your opinions on this one!

 

Me too, just spent a load of dosh on ICE.. and what to change the back box.. will be interested to see if it works too

 

I'm interested in seeing my opinion too...
Looks like it should do the right sort of thing for the backbox problem - there's some of the kind of dynamat style sticky stuff for the rear wheel arches, under-bonnet/bulkhead & boot lid, but the bulk of it (and weight of it!) is what appears to be a seriously heavy vinyl floor covering with foamy stuff filling that's cut-to-shape. The sort of thing that BMWs have in them, only more so, which can't be bad...
I think someone else has already put this stuff in? Helloooo out there - any comments?

 

Could I be so bold as to ask what the BJ Acoustics kit cost you? ...and how long it takes to fit it all

 

It's 200 quid, and if you join the SIDC you get a healthy discount due to them advertising in the SIDC's esteemed organ...

http://www.bjacoustics.com

 

Coincidentally, I joined SIDC last night

 

Nom - I look forward to hearing how you got on with fitting the kit (how easy it was and how long it took). Any chance you could take a few digital snaps and post them up so we can see what you get for your £200 and how it fits?

BTW - the glass bits that go up and down do adjust the back box sound track nicely but are limited in their usefullness by the wet stuff that keeps coming down in this country!

 

I'll try to remember to take the camera (haven't got one of my own - I have to borrow the office one). I'm pretty good at forgetting it, though, so no promises! Timewise, I'll have a go, although I'm also going to be putting my rather complicated amp back in again (been away for a service) so the timings may be a bit off.

 

Well, I've fitted the BJ acoustics kit now & did take some pictures, but they're on the camera & I don't have the kit to get them off on the machine I'm on at the moment. Broadly speaking, it took an hour to do the engine bay, an hour for the middle and an hour for the boot/back seat area, making a total of four hours. Yes, that doesn't add up... Something to note is that it's really quite heavy - the whole kit's probably about 35kg at a guess.
Firstly, let me tell you that I'm cr4p at judging noise levels, I just moan about how noisy the car is. Also, I had a fair bit of Dynamat stuff in the car before fitting the kit, which reduces the effectivenes - well, doesn't give a good base or whatever it's called to judge against.
To me, the main difference is that the noise is 'softer', although I have turned my "dangerously safe piece of road with gatso on it" detector down two plips, which means that everything must be quieter. The sound proofing is loosing the battle against the SS backbox, though, but it does cruise noticeably less boomily. I'd be very interested to hear the whole set up with the standard (or at least a quieter) backbox - I think in that situation the soundproofing would work very well. Definately not up to beemer levels, though - I went in a 3 series just afterwards & it was far quieter, again though that might have a lot to do with the backbox again...
On the fitting side of things, it's all OK except the £^&*£%^&£"$ things on the bonnet underside to keep the standard 'soundproofing' on. I only got 2 off without destroying them & had to replace the others. I might have been doing things wrong, but I just don't think that they're there to be replaced. There's also a bit too much kit for under the bonnet - there are parts for the air inlet & fake plasticy bits as well which can't be used, but I just stuck them in the boot instead...
The £180 (or £200) asking price seems quite a bit, but I think that it's worth it, certainly if you don't have any soundproofing at all, and especially if you don't have a SS BB :-)

 

Well, I visited my local Carpet Right where a very nice man gave me about 20 feet of underlay FOC because it had some small rips in it. I laid it under the rear carpet and under the rear seats. Total time including cutting to shape - 15 mins. There is quite a noticable reduction in sound from the ScoobySport back box but I also already had quite a bit of Dynamat in the boot.

Bearing in mind that the BJ Acoustics kit is £200 I may well go and scrounge some more underlay for under that carpet in the cabin and under the trim panels on the wheel arches & buy some Dynamat for those locations as well.

If all of this fails I may swap the back box for a different one - any suggestions?

 

Not much of a suggestion as I don't know the thing yet, but I've heard 'quiet' things about Remus - it's meant to be as quiet (or quieter than) the original box but allow a greater flow. I thought that those two things were pretty much mutually exclusive?
I suppose it all depends what you want - in my case I want everything (a quiet exhaust that sounds great), but it doesn't work, does it? Swap'em over depending on mood, I suppose. Or turn the stereo up so deafness sets in in a couple of years?

 

I'll have a look to see who supplies the Remus - it has to be less expensive than the whole Prodrive system! People say good things about the Power Engineering system - available as a whole system replacement with a high flow cat or just as a back box. Once again, I haven't hear it yet so don't know how loud. I understand that most of the Japanese systems are v. loud. My problem is that I too want everything - nice sound for a quick blast but quiet enough to do 15,000 business motorway miles each year without giving me a head ache.

 

Someone needs to design a quick-release backbox system.
That would do it for me

 

I had BJ Acoustics do my MY01

Excellent results

I payed for the guys to come and do mine

The wife who moaned like hell when I had the PPP fitted fights for the keys again

Phil

 

Tried out a Remus backbox this weekend instead of the SS to see what the BJ Accoustics sound deadening stuff was like without a machine gun mounted in the boot. Now feels like I drive a magic carpet. A nice quick, quiet one at that.

 

If you don't mind me asking, how much was the Remus back box?

Also, have you noticed a difference in power?

[Edited by necromax - 10/29/2001 1:13:56 AM]

 

The backbox was about 170. For that amount I thought it was definately worth trying! Looks pretty funky too - two pipes the same size as the SS which only just cram into the slot!
Difference in power... well, pretty similar to the Scoobysport. There's always this argument over whether the backbox can make any difference - I found when the SS first went on, the car certainly felt quicker and also revved better/higher. There was no noticable drop swapping to the Remus, so presumably it's doing its job pretty well
It's only mild steel, though, so probably won't last as long as others. Most likely bored with it before it wears out anyway

 

£170 seems very reasonable compared to some, I think I'll go withthe Remus. Where did you end up getting it from?

I'm thinking of a Magnex Twin downpipe & perhaps a decat centre section... I think it will all fit together

 

I got it from Elite something-or-other, I'll find the web address... http://www.elite-design.co.uk (sorry - don't know how to do links). They're in Rainham but will presumably deliver.

Interested to hear how it goes with the Magnex dp & centre - that's my next step!

 

I read on a another posting Halfords of all places is good place to get Magnex.. FREE fitting. Not sure how much the units themselves cost, will be investigating, will let you know

 

Apparently the Magnex downpipe is £179.99 fitted!