21 replies to this topic

[germini30]

Used my mini yesterday, first time for ages.
Forgotten how noisy it is inside.
I'd like to do something to make it easier on the ears if I can.
Current setup is,
1275cc with 3.44 diff
Drilled airbox with K and N element
Maniflow free flow manifold
Single side exit stainless exhaust, of which the brand is unknown.
Car has sound deadening under the carpet and under the bonnet too.
Which of these would make the most noise internally?

[sonikk4]

Used my mini yesterday, first time for ages.
Forgotten how noisy it is inside.
I'd like to do something to make it easier on the ears if I can.
Current setup is,
1275cc with 3.44 diff
Drilled airbox with K and N element
Maniflow free flow manifold
Single side exit stainless exhaust, of which the brand is unknown.
Car has sound deadening under the carpet and under the bonnet too.
Which of these would make the most noise internally?

 

Look at the exhaust first, is it just plain noisy or does it reverberate. The drill air box will add noise as its literally just the other side of the bulkhead. The soundproofing, what is it exactly??

 

You have to remember there is next to no insulation in a mini, they have always been noisy compared to a modern car so not really comparable . Yes adding extra insulation will help to a degree but will never bring it up to modern car standards.

[germini30]

The exhaust is loud from outside so I've been told, like a deep note. Sound deadening is like an underlay I bought from minispares and does the bulkhead too.
Maybe I'll try and get a standard air box and look and twin box side exit exhaust

[stuart bowes]

you could try gaffa tape over the holes for now just to see what difference it makes

 

obviously not ALL of the holes lol

Edited by stuart bowes, 19 May 2025 - 03:07 PM.

[germini30]

Haha, someone I know has an airbox locally I can have

[mbolt998]

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[germini30]

Haha nice

[mab01uk]

You might find the link below on BL's "Quiet Mini" improvements and research an interesting read.

 

The Quiet Mini - 1980

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.

Motor Magazine - July 5th 1980:-

https://www.theminif...uiet-mini-1980/

 

For a quieter exhaust which is also good for performance in tests by David Vizard, I would recommend the Minispares twin-box RC40 classic system:-

https://www.minispar...and-fitting-kit

Edited by mab01uk, 19 May 2025 - 04:44 PM.

[alpder]

I have a 1275 van, drilled airbox with K&N, Freeflow/RC40 2-box exhaust (out the rear). And the noise at cruise is very unpleasant - almost all of it is extremely loud low-pitched exhaust drone. I have tried earplugs, and ear defenders, and both together, and even Bose noise-cancelling headphones. The sound is such low frequency that none of them make any difference.

 

But I hadn't fitted the straight s/s tailpipe supplied with the RC40 kit - because I didn't fancy the bling. Yesterday I experimented with fitting it, so that the exhaust now pokes well out the rear, instead of ending under the rear valence. The noise reduction is astonishing - seemingly just because the outlet is a few inches further back. So I'd say look at changing that side-exhaust.

 

You can try taping up the drilled airbox holes - certainly worth the experiment. My experience (going from a cone to a standard box+K&N and then to the same box but drilled) is that the drilling makes little difference: the airbox is still pretty quiet (certainly compared to a cone). Only time I notice intake noise is at full throttle.

[alpder]

Also, I've just been going over Keith Calver's tech articles on exhausts. He tested a few variants for both performance and noise. Worth a read.

[bpirie1000]

Upgrade the stereo..... proper genuine old school method to fix engine noise...

[germini30]

My exhaust is rear side exit but only has a backbone. It ends short of the rear bumper, so maybe I'll get a twin box exhaust and a standard air box

[mab01uk]

Although stainless steel exhausts last longer they are also usually slightly noisier than the equivalent mild steel exhaust, due to there higher resonant properties.

 

Mini Exhausts - Keith Calver:-

"The most efficient exhaust system you can fit to our Mini to provide optimum performance (both power and economy) will be one that maximises gas speed, shock wave tuning, and fits well. So you want one that’s got a 1.625” bore, follows the standard exhaust route to give best length, and has straight through, efficient silencing (two silencers usually needed to get noise down to a sane level), and is well made for an easy fit. A good finish will help in the aesthetic stakes too! That'll be the RC40 then, or more recently the Mini Spares Millennium range."

https://www.calverst...ic-information/

Edited by mab01uk, 19 May 2025 - 07:47 PM.

[germini30]

Thanks for the replies everyone.
My current exhaust is about 2-3 inches shorter than the car. I've been getting a few fumes inside too.
Think I'll treat myself to a twin box side exit RC40 and get the undrilled air box too

[stuart bowes]

the induction noise should be more of a sucking, like a sort of sccchhhhhhhhhh kind of like white noise, mostly fairly high pitched, that's what you'd get rid of by taping up the box 

 

if it's more of a deep rumble kind of engine note sound that'll be exhaust and/or vibrations, something rattling on the bodywork maybe, that sort of thing

 

sounds like you have both covered anyway

Edited by stuart bowes, 20 May 2025 - 09:05 AM.