Sound deadening on the cheap!

Cobber wrote:

Given that it would seem that the carpets fit so much better with a layer of underlay fitted, has gotten me highly suspicious that the carpets were designed to be used with underlay in the first place and some parsimonious bastard bean counter has interfered at a late stage and deleted the underlay in order to save a few shekels!

Nothing gets past you Cobber!
It was definitely cost cutting to not put any deadening in the cars but there is factory underlay under the carpets. I just beefed it up!
 

Had lunch out. My road back home over the mountains but due to an occupant of the significant kind in the passenger seat it was only at a brisk pace..but it was very refined..😉 

Yes it's always difficult to get the best out of a car on a mountain road, with the minister for war & finance present, ready and willing to cross the floor to join the opposition and making a motion of a vote of no confidence at the slightest display of enthusiastic driving!

That’s a route home! I can almost feel the road through the seat of my pants, especially through the twist & jinks on a road like that.
I’ve a similar road about five minutes from home, not quite as long & with less extravagant scenery.
M

Another area to consider for sound deadening is the back of the panels surrounding the side air intakes. I am not sure if it is different for the MGF, but on an MG TF if you tap on the panel surrounding the air intake grille it sounds hollow and terrible. There is basically one large thin metal cosmetic panel that runs from the rear of the car all the way to the front of the the sill area. The area around the vent opening has very little structural support and will rattle if you tap gently on it. Compare this panel with your recently sound deadened door panels and you will observe quite a difference!

If you remove the vent cover (easy to do - see other posts for this) and remove the black plastic air tube, you can access a fair amount of the back side of the metal panel (well not so much in the forward sill area unless you have very thin arms and small hands). Clean it first then apply sound deadening material as far as your arm can reach in all areas. The difference will be quite remarkable.  
Clean out your 4 sill drain holes while you are at it.  

You can also access the rear area of the panel via small openings in the boot area on the sides behind the carpet.
The front sill area cannot be accessed (for sound deadening). 

One thing occurs to me & that would be exterior fitting.
The sills are prone to stone chips. Obviously stones chip the paint & promote corrosion, painting the sill with stone chip is a recognisable method of overcoming this, why not run a strip of this glorious stuff down the sill & having made sure the sill is clean, use that as stone chip & a method of reducing panel resonance?
Properly prepared it could be sprayed body colour.
Just a thought.
M

Goodwood wrote:

Another area to consider for sound deadening is the back of the panels surrounding the side air intakes. I am not sure of it is different for the MGF, but on a MG TF if you tap on the panel surrounding the air intake grille is sounds hollow and terrible. There is basically one large thin metal cosmetic panel that runs from the rear of the car all the way to the front of the the sill area. The area around the vent opening has very little structural support and will rattle you tap gently on it. Compare this panel with your recently sound deadened door panels and you will observe quite a difference!

If you remove the vent cover (easy to do - see other posts for this) and remove the black plastic air tube, you can access a fair amount of the back side of the metal panel (well not so much in the forward sill area unless you have very thin arms and small hands). Clean it first then apply sound deadening material as far as your arm can reach is all areas. The difference will be quite remarkable.  
Clean out your 4 sill drain holes while you are at it.  

You can also access the rear area of the panel via small openings in the boot area on the sides behind the carpet.
The front sill area cannot be accessed (for sound deadening). 

Thank you for that help! 
I am so impressed with what has been done that I know I need to do the rear quarters and boot. I never considered behind the vents but you are quite right it does rattle around there.
so far I have added around 17lbs to the car which is nothing compared to what it has done for the ride!
Thanks.
 

Airportable wrote:

One thing occurs to me & that would be exterior fitting.
The sills are prone to stone chips. Obviously stones chip the paint & promote corrosion, painting the sill with stone chip is a recognisable method of overcoming this, why not run a strip of this glorious stuff down the sill & having made sure the sill is clean, use that as stone chip & a method of reducing panel resonance?
Properly prepared it could be sprayed body colour.
Just a thought.
M

Good idea!
That is very doable. It would need to be clean which is easy to do and the tape has a very good edge to it.
The black Bostik tape has a very good tape on top of the bitumen that doesn't crease when you fold it over seams or edges. It remains flat.
Something else I have to ponder..

You could even consider just painting the underneath portion of the sill (only). This would not be visible but it would still reduce noise. I find the sills make quite a bit of noise when dirt is kicked up from the font wheels and resonates when it hits the underside of the front sills. That said, I guess one could also opt for front mud flaps for the same effect. 
There are also internal frame sprays that might have the same effect from the inside. Not sure, never tried this. There are access holes for spraying into the front sills in the front wheel wells behind the plastic wheel guard. For example:
Eastwood Internal Frame Anti-Rust Coating, 14 oz. Spray
 

I am planning on treating the underside and inside the sill panels with Bilt Hamber spray as soon as I can. 
The underside is imaculate and I want it to stay that way. I need to lay it up in my garage to do a really good job but my closet Queen MX5 resides in there just now until it sells. I daren't put it outside and let it get dirty or wet! It is a problem I brought upon myself.
I will be doing the boot and the iner wings from the air vents with bitumen tape at the same time.

Just had a wonderful ride in my little car around my country roads circuit of about 15 miles with a lovely quiet and rattle free chassis.
That's all, nothing further to report..except..did I ever tell you I love this car?

Inspired by your comprehensive application of bituminous padding & having already done the more resonant panels, I went around the car tapping panels to see which “rang”.
I’ve done a bit more, easily subduing clangy bodywork & earmarking those to be treated.
Only when out of hibernation will it’s effectivity be noticed; it can’t make it worse.
M