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A Quiet Mini


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#1 gkmini

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Posted 01 November 2013 - 11:48 PM

Is it possible?

 

I've been doing a lot of research into the topic for quite some time and I've seen all the posts. "Get some ear plugs." "If you wanted quiet you should of bought a Chrysler." "Rickety is right."

 

And like all proud owners, I did love the fact that my Mini sounds like a roaring Spitfire at one point. But now that I'm opting for sexyness over quirkyness, I'd like my ride to be as silent as possible while I cruise to some cool jazz.

 

Of course I'm not going to forsake a nice sounding exaust, possbily something by Maniflow with that Jaguar growl. I just thought there might be some other solutions in the way of adjustments to engine steadies, uprated dampeners, or standard air filters.

I'd also like opinions on the best quality sound deadening set up for the best price. Currently I'm looking to go forward with Dynamat Xtreme and closed cell foam on the floor, kick panels, roof, doors, bulkhead inside and out, as well as behind the rear seat and underneath the bonnet.

So if you or anyone you know has ever achieved the impossible and created a quiet Mini, please feel free to discuss here.

 

Cheers,

- GK



#2 mab01uk

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Posted 02 November 2013 - 12:44 AM

BL launched the 'Quiet Mini' in the Summer of 1980. It incorporated extensive sound-deadening in the floorpan, front bulkhead, dashboard, roof and boot, plus a new headlining material. The effect was to produce what could more accurately be called a 'quieter Mini'. Over the years it was slowly reduced under cost reductions and in the front floorpan area it seemed to promote rust by trapping the water leaks.



#3 1984mini25

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Posted 02 November 2013 - 01:17 AM

One of the 998 minis fitted with a 2.9 diff for lower cruising revs like the citys, 25, early sprites etc. Along with a standard air box, standard 'pea shooter' exhaust, 145/70 tyres and thick carpets.



#4 gkmini

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Posted 02 November 2013 - 01:45 AM

BL launched the 'Quiet Mini' in the Summer of 1980. It incorporated extensive sound-deadening in the floorpan, front bulkhead, dashboard, roof and boot, plus a new headlining material. The effect was to produce what could more accurately be called a 'quieter Mini'. Over the years it was slowly reduced under cost reductions and in the front floorpan area it seemed to promote rust by trapping the water leaks.

 

That's interesting. I took out all the bitumen liner that was previously on my floor out because it was cracking, but I also tore out a few of the floor panel plugs (the thin little circles with the x on them) in the process. I better get that seen to before I put any deadener down. At least it's good to know that it IS in fact possible to make a quiet Mini.

 

 

BL launched the 'Quiet Mini' in the Summer of 1980. It incorporated extensive sound-deadening in the floorpan, front bulkhead, dashboard, roof and boot, plus a new headlining material. The effect was to produce what could more accurately be called a 'quieter Mini'. Over the years it was slowly reduced under cost reductions and in the front floorpan area it seemed to promote rust by trapping the water leaks.

 

Hopefully I can achieve the same results with the Dynamat. Ive been looking at Raamat too. I hear it gets the same results but for a fraction of the cost. I think if I minimize the amount of engine vibration, it should cut down a lot of the road noise. Maybe if I double up on deadener on the firewall in the interior as well as in the engine compartment I can cut down on engine noise too.



#5 surfblue

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Posted 02 November 2013 - 09:04 AM

A classic mini is never going to be quiet, not to modern car standards even with the addition of extra sound proofing. You have a big lump of cast of iron engine block just inches in front of the bulkhead with an exhaust manifold in between you and it. Add in the racket of drop gears and less than streamlined aero dynamics and you are never going to make it limousine like quiet.

I love the mini noises, its all part of the experience! 



#6 HarrysMini

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Posted 02 November 2013 - 10:43 AM

Silent Coat is every bit as good as Dynamat without the stupid price tag.

#7 olds_kool_lews

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Posted 02 November 2013 - 12:54 PM

A standard well looked after engine, pea shooter exhaust and plenty of sound proofing will make a mini quiet,

#8 mab01uk

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Posted 02 November 2013 - 04:36 PM

Available from Somerfords:

https://www.somerfor...age=page&id=139

 

Sound Insulating Felt
Somerford Mini have acquired the stocks of original 1990s Mini sound insulating felts from the Rover parts organisation, XPart.  These felts are all factory precision die-cut for specific areas of the bodyshell, including bulkheads, inner wings, toeboard, dash, sills and footwells and most feature cut-outs and holes for equipment found on each model.  As a result, there are several variations of each felt - too many to list here!  If you require original factory insulating felts for your Mini, please contact us for details.

We hold a choice of three under-bonnet soundproofing products, each coated with fire-retardant facings and intended to be applied with trim adhesive to the underside of the bonnet: 

 

Sound Insulation
Many attempts have been made over the years to reduce the cabin noise in the Mini, with varying degrees of success; none have quite removed that 'bouncing along in a bean can' sensation we all know and love (?) so well.  Two attempts stand out particularly.  The first, after the demise of the 850 saloon in 1980, involved stuffing large amounts of sound deadening material onto the floors (replacing the hessian backing on the carpets), in the companion boxes, on the dash and on the roof.  Triumphantly labelled 'The Quiet Mini' by the marketing department, it sort-of worked.  Can any of you really tell the difference, though? 

The other serious, and ultimately more successful, anti-noise campaign took place during the development of the 1997 on model.  One of the forthcoming European regulations that had to be passed if the Mini was to stay in production after 1997 was the drive-by noise limit - i.e. the aural impact the car would have on its immediate environment.  Once again, sound deadening material was beefed up, but it still required exhaust modifications, the repositioning of the radiator to the front of the car and the raising of the final drive ratio (so the engine wasn't running so fast) plus a host of other changes to get the Mini quiet enough to pass the tests.  It did pass, obviously, and the 1997 on Minis are genuinely noticeably quieter both from the outside and inside.  Only one other Rover Group product had to turn similar engineering cartwheels to pass the drive-by noise test: the Land Rover Defender.  Says it all, really...

Sound insulation material in the Mini takes two forms - bitumen self-adhesive pads affixed to the insides of the larger panels to prevent them from drumming, and thick felt or foam sheets against both sides of the dash and on the floors.  Leave them out at your peril - the noise level in an uninsulated Mini is astonishingly loud.

 

The fire retardent felt engine bay dash pads we stock are rationalised from the original countless variations down to two.  The 1959-69 dash pad is tailored for inboard bonnet hinges, early (square) wiper motor mounting and the fresh air duct passing through the dash that many Minis of that period had fitted.  The 1969 on dash pad is cut to the correct outline but leaves the job of tailoring for the myriad of dash mounted equipment fitted from 1969 on up to the customer - which is no huge task, because the majority fix by screws through the dash pad anyway.

 

We can also supply additional quantities of insulating felt from bulk stock.  It is sold by the square metre, from a 1 1/2 metre wide roll (i.e. if you ask for one square metre you will get a rectangle of felt 1 1/2 metres by 2/3 metre).  It can be used for any interior or boot application, common uses (other than floors, which are covered by our underlay set) being:

Lower dash (under parcel shelf) Upper dash (above parcel shelf, behind dash liners)
Pair of front wheel arches
Boot floor (originally used on more upmarket 1959-75 models)
Underside of rear parcel shelf (originally used on 1959-69 models)

Offcuts can be used in the companion boxes, which were also felt insulated in the factory.

 

Sound Deadening Pads
The CHM228 sound deadening pad is an industry-standard product used by motor manufacturers for many years.  It is designed to prevent vibration in large expanses of sheet metal which would otherwise drum when the car is in use.  Following factory practice, application of pads around the body should be as follows: one inside each door skin, one inside each rear quarter panel, two inside the roof, one in each front footwell, one in each rear footwell, two on the centre tunnel and two on the rear seat pan. 

Being bitumen based, sound deadening pads are extremely brittle when cold.  Even on a warm day they should be carefully heated with a hot air gun or similar until they are sufficiently ductile to follow the contours of the panels to which they are being applied.  They can be made to follow extreme contours such as deep floor ribs using heat - something you wouldn't believe when the pads are cold.  One final word of advice - if your Mini body is due to be painted in an oven, don't apply sound deadening pads to the roof until afterwards, unless you want a really painful job chipping all the melted bits (by this time set rock-hard) off the floor and rear seat area.



#9 Archived2

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Posted 02 November 2013 - 05:09 PM

Ive had loud minis and then some very loud minis with big exhausts on the back. Ive been in a mini thats had the works as far as sound deadening goes and he spent a small fortune but I couldn't see it made enough difference to make it worthwhile.



#10 mab01uk

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Posted 02 November 2013 - 06:56 PM

Motor Magazine - July 5th 1980

 

QuietMini-1_zps0f2f1ddb.jpg

 

QuietMini-2_zpse448c2bb.jpg



#11 gkmini

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Posted 04 November 2013 - 07:39 PM

Thanks everyone! This is all valuable stuff in my quest for a quieter mini. I've got a few ideas. I'll post a video in the spring once my restoration is complete.

Cheers,

GK




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