Soundproofing

[phil r]

I've got a 98 Elise super 140 and with my new job I commute 60 miles a day on the motorway and my ears are now ringing. I refuse to sell the car as I love it to bits and am not buying another car. I have read that the S2 has 'tuned insulation to cut cabin noise.' Has anyone fitted extra insulation between the bulkhead and driver in the S1? Has anyone fitted insulation to the canvas roof? Any advice? PS I can't afford a hard top!

[ATG]

(little foam rubber ear defenders maybe, the type you shove into your ear?)

[bert]

I can't really compare the s1 with the s2. anyway, driving the s2 on motorways is also very annoying. I suggest that you look for a good pair of earprotection and look for an alternative road to enjoy your ride.

[adeewuff]

I've driven both cars and the only real difference was that the S2 exhaust sounded less 'boomy' ie less lower frequency resonance. I would say at speed they are pretty much the same, the main problem being wind & tyre noise rather than the exhaust. The engine speed at 80mph is higher in the S2 compared to the standard S1 due to the shorter 4th and 5th ratios so again no real benefit with the extra insulation.

All I can recommend are some some wax earplugs as sold by Boots!!

[adrianr]

Yes, the S2 is a lot more muted. Possibly easier to live with, but perhaps not in the spirit of the car. Anyway, few suggestions you might like to consider:

i) Refit the standard exhaust and airbox - unlikely you'll notice any performance drop; or if you want it loud-but-nice and don't mind the cost, try the Raceline system.
ii) Put some cut-to-shape soundproofing carpet under the seats and on the rear bulkhead;
iii) Always drive with the top down; windrush is far preferrable to tarmac drone.
iv) Check what tyres you're running; the OE P-Zeros are a lot quieter than some of the aftermarket ones.

Cheers,
AdrianR
(and when you get bored on the M-way, turn off at the next junction and do a couple of laps of the exit roundabout....)


>> Edited by adrianr on Tuesday 29th January 12:31

[atg]

When I was bilging out a flooded MkII Golf I found a sort of jelly filled bubble wrap laid underneath the thick felt sound proofing layer in the foot wells. I assume it was another layer of vibration and sound proofing. If you go along to a breakers yard, i imagine you get hold of this stuff and experiment with it on the bulkhead.

[phil r]

Thanks guys, I'll do some experiments with some off cut carpet and underlay next weekend. Just to be slightly sad I'l borrow my works sound pressure level meter for an objective view. If anybody is slightly interested I'll post my results!

[phil r]

Hi guys
Well I have now defiled my elise with an extra 2kg of unneccassary mass, Colin Chapman would not be impressed.
I first recorded some baseline sound pressure levels with no extra soundproofing (sports exhaust cloth roof) dry conditions (Quiet aphsalt) no stereo on!
The settings on the meter was profile A as opposed to B and slow response.

mph Sound pressure level passenger head level Idle 63dB
30 72dB
50 81dB
70 83dB
80 84dB
90 88dB

Note. 90dB is the safe working limit for 8 hours (per day I assume)

I have added the following soundproofing
8mm felt and extra canvas layer to the roof
Daynamat original to the aluminium part of the rear bulkead and floor (drivers side)

I got the following results on the same road, note it was now raining hard.
mph Sound pressure level at passenger head
Idle 61.5dB
30 72dB
50 80.5dB
70 82dB
80 -dB
90 -dB

The soundproofing has produced an improvement of 0.5-1.5 dB which is equivalent to the measured change in my car stereo volume of 1 to 2 'clicks' even with eatra noise of the rain pouring down. I will borrow the SPL meter again in a couple of weeks.

In the dry the improvement is appparent and I can talk on the motorway with out shouting.

I am taking further steps as I have found that Lotus sells a carpet set for the Elise mk1 which covers the floor, sill sides and I believe all of the rear bulhead. I am having this fitted next week so I will let you know how things go after that.

[phil r]

Hi guys
I have now got the carpet set which looks very good (Thanks Haydons of Salisbury) the carpestc cover the floor, the aluminium part of the rear bulkhead and half way up the sides of the sills. They are well finished and don't look out of place. I have recorded data.

Mph/ original, mat and roof, and +carpets
Idle 63dB(A) 61.5dB(A) 61dB(A)
30 72dB(A) 72dB(A) 71dB(A)
50 81dB(A) 80.5dB(A) 78dB(A)
70 83dB(A) 82dB(A) 80dB(A)
80 84dB(A) -dB(A) 81.5dB(A)
90 88dB(A) -dB(A) 82.5dB(A)

The improvement is very marked the faster you go.

[petertimmins]

I was very interested in your results as I am also considering a carpet set for my 99 S1 with hardtop. I do not really understand about decibels but is a drop of 3db that noticeable? Are there any other advantages to the carpet set as it seems very expensive for a few square metres. Any problems fitting it or did yoy pay the dealer to do it?

[edgley]

How much was the full set please?

Cheers,

simon.

[Englishman in LA]

3 dB is half the level (log scale and all) so a drop of 3 dB is very significant.

Steve

[ATG]

dbs are indeed a log scale ... but your hearing is logarithmic too. If you check out the numbers it is now as loud at 90 as it was originally at 60, which sounds like a serious improvement to me.

[petertimmins]

Carpets might be a good idea then. The hard top increases engine noise considerably.

[phil r]

The drop in noise level was very noticable and I have a loud Elise with the BBR SS sports exhaust which is quite boomy. The cost of the carpets and installation was about £300 but get a quote from Haydons.
After some weeks with them I am very pleased as the drive top work is a lot less tiring (I know it isn't a commuter car but tough I'm keeping it!) BTW I took the Elise to Bedford autodrome about 3 weeks ago. Awesome, you have to do it. It was wet and I spun a few times but I learned an awful lot about skid control and maintained my first proper powerslide!

[Nightmare]

elise carpets....order them direct from autostyle (www.autostyle.co.uk) They make ALL Lotus carpets, and are LOADS cheaper direct. Plus you can get it in any colour you like instead of the standard ones! Oh, and thicker than the standard ones if soundproofing is really your bag!

cheers
Night

[Adrian G]

Interesting reading about sound proofing. In my Mrk 1 Elise I sound proofed the whole interior with carpet insulator from John Lewis! Felt on one side and black rubber on the other. Two layers on the floor and four layers behind the seats. It made a huge difference, particularly the layers behind for the engine. Took quite a while to cut all the bits up, but it was a sunny day and well worth it. Used double sided carpet tape to stick it all down. My Mrk 2 is much quieter, but i'm going to use a similar method to insulate this (when it is sunny). It really does work - honest. Adrian G