For those of you who have added sound insulation (Dynamat, etc.), did it make a difference?

Marginal.

The doors do make a nice "thunk" when you close them though

 

Small amounts of dynmat can solve for the tinny sound when panels vibrate. But you don't need to cover everything with it. eg. A 6 inch wide strip inside the door will do the technical job, a one foot square in the footwells, etc.

Some insulating rubber foam will also mute the reflected sounds, and I would use more of that than the dynamat.

I can only imagine the hassle of a future restorer dealing with butyl rubber fused to everything, degraded aluminum flaking off the dynamat, etc.

 

I haven't put it in my Ferrari (and won't). I let myself get talked into having it installed in my 911, and quite frankly it made no difference. Waste of money.

 

Not in my 328, haven't had the carpets out yet given the general condition of the car is not necessary .
I did it in my Lancia Montecarlo. Old ones cleaned up from the bottom and back wall and new ones installed, not the brand product but alternative. Keeps shaking with the buttocks

 

I see it used all the time but never understood what someone was trying to quiet.

For example, Dynamat on one with a Tubi...

 

I added sound deadening everywhere in the cabin (e.g., undercarpet, seats, and in the doors both outer panel and inner panel) and in trunk

I used as thick as possible material depending on where I placed it, but from Amazon. Quiet affordable.

Door does close with a thick "thunk". For rest, I do not know yet as my car it not quite operational yet.

But it feels good

 

I haven't done it in my Ferrari, but I also own a 77 Datsun 620 truck. It was one of the loudest vehicles I've ever been in. The sound was not from engine noise, but from constant road noise and rattling. I removed the carpeting and seat, and covered the entire thing, from the bottom of the rear window, to where the dash mounts up on the firewall, in 80 mil kilmat, and also put some big strips of it in the doors. Under the seat and on the wall behind the seat up to the rear window, I also installed half inch thick foam insulation. Now I can have a phone conversation on bluetooth at 65mph no problem. Anecdotally, all the insulation seems to have helped the heater work a bit better in winter. I am a big fan of adding insulation

 

I have the cheap Amazon Dynamat in my 04 subaru wagon - it has a 3" exhaust but factory cat. The car drones. the older wrx's have very thin metal on the body. I did the inside of my doors and behind my dash when I upgraded the stereo. I also did along the trunk floor below the interior panels. The car still drones. The doors have a more solid feel and the dash doesn't rattle compared to how it used to. I really need to add a resonator to the exhaust.

What are you looking to improve? creaking or engine noise or both?

 

I just went for a 20 minute drive test drive with my 8 after adding sound deadening (and lots of other stuff). I think it made a VERY noticeable difference. To be specific, I added "Amazon Dynamat" as follows:

- 10mm thick on entire floor, and under pedals, and as much as possible of the center tunnel (removed seats etc) (had nothing there originally)
- 10mm thick on sides underneath rear window (had nothing there originally)
- 4mm thick on inner side of outer door panels and also on inner side of the inner door panels (and the interior leather on top of that) (had nothing there originally)
- 15mm thick behind and underneath rear seats (replacing the prior material which was aged)
- 4mm thick in the trunk area (had nothing there originally)
- new headliner that has some cushioning built-in, but no official sound deadening material (I used velour type lining with foam on back)

I tried to cover "100%" in the areas described above but was not annoyingly precise in that respect.

I cannot quantize a "percentage of improvement" but it is quite noticeable and the car sounds more solid and less small noises. Engine still sounds beautiful.

I have an Ansa exhaust which is ok but when I shake the exhaust I hear rattling inside -- will probably change to a Borla exhaust eventually.

 

I did the floor and doors with Dynamat Extreme in 2014. I really like the effect.

As already mentioned, it quieted down the higher frequency "rattling" sounds (to me it was the sound like imaginary pea gravel spraying on the undercarriage from the tires). The engine rumble got through loud and clear and, if fact, sounded better after adding the Dynamat.

Also, like everyone said, the doors closed with a nice solid sounding whump.

 

I would say get an exhaust. Single tip exhaust is a strong constraint because most new, used, OEM or aftermarket will be quad tip. And I am guessing your rear valence only has the one exhaust cutout to match..

If you have the OEM or a high quality aftermarket - take it off and pack it away in storage.

There's a bargain Ansa on ebay right now for $6,300 and change.... https://www.ebay.com/itm/185550996875 - on what planet?!?

I would go get something made. You would be looking for a Transverse 2 into 1 muffler. Most of them look like they have entry on each side, like you need. The exit looks like it's in the middle - so you have a hard 90 bend then get your exhaust to your valence cut out. You could even add an additional resonator there to tune the exhaust noise.


https://www.flowmastermufflers.com/products/exhaust/mufflers/flowfx_mufflers/parts/72206
https://vibrantperformance.com/transverse-oval-universal-mufflers-v1248/ - Vibrant makes good stuff - They also make some of of the best resonators
https://www.borla.com/catalogsearch/result/?q=transverse - borla has a few options
https://valvetronic.com/products/universal-valved-exhaust-kit - this one to has a valved exhaust w/ a keychain remote to open / close.

All of these could be made to work. less than $2K. Just save your original. If you ever sell the car - sell with both or sell the one the new owner doesn't want.

 

If you have a GTS, put the roof on and it's quieter. But I don't know that it would ever be "comfortable" on a long trip as far as sound. I also have the stock exhaust and like the sound, but I would imagine after a few hours it getting very old very fast.

 

Its like having a high maintenance Italian girlfriend who's only volume setting is loud.

When I did the Dynamat it brought the decibels down from a constraint 95 db to 75-80 db.

 

Game changer for longer highway drives are ear plugs.

No joke, I wear them when I ride motorcycles to protect hearing from wind noise & one day i thought....hang on a minute, why am I not using these in the car???

 

Dynamat etc will make the car feel & sound less tinny, more solid & may cut some vibration/ resonance, but it's not going to make it quieter overall.

When I bought my car it had a stainless exhaust on it. I swapped it for a standard one before a long trip in 2011 ( which was quieter) & it stayed that way till last year when i swapped it back.

I no longer use the 328 for big trips so I thought why not. Its for sure louder, but what I hadn't banked on is it seems to breathe and run much better with that exhaust on it so it's staying & I'll wear earplugs when I need to!

 

I don't think a single-tip has to be a constraint....it's more about the volume of the pipe(s) rather than the number. If you look at some of the early V-12 cars, their four exhaust outlets are tiny. I have a single-outlet exhaust as well and will be looking to get rid of the boat anchor masquerading as a muffler and improve the flow.
Edit: It just dawned on me; you probably meant the single-tip was a constraint when it comes to fitment of a replacement exhaust, not that it constrains the flow. Got it. Duh. /Edit
Thank you for posting the link to those transverse-style mufflers....I don't know how, but I've never seen a muffler design like that before....my eyes have been opened! ...although I am curious how the exhaust flow is routed inside the muffler.
Also, I can vouch for the Flowmaster FX series mufflers. I put one on my mildly breathed-on Vanagon behind a cat and 4>1 header and it had the most beautiful, mellow sound, but would still set-off car alarms due to its straight-through design.
- Dave

 

The solution to making a 308 a quiet highway car would be changing the gearbox. Cruising in 5th gear at 4,000+ rpm is never going to be "quiet."

 

You are not wrong & in comparison to modern cars the thing feels like its gearing is too short.

But take it to its proper habitat i.e. some mountain roads & you'll understand exactly why its set up the way it is and I wouldn't change it.

Years ago (before I'd really understood that) I went looking for solutions to raise the gearing. The obvious one is simply to increase the wheel diameter but I've rarely, if ever, seen wheels I like better than the standard ones and I don;t really like the look of bigger diameter rims under a 308/328. Maybe 17s, but no more than that.

More elegant would be to do something with the drop gears similar to what Michelotto did - except they went the other way & made the gearing shorter for track use (and they were straight cut gears so incredibly noisy!). Even then I'm not sure if it would even be possible without remaking the cover. It would be mega expensive to get them made. Changing some or all of the gear ratios was obviously beyond a daft idea.

After a while I came to the conclusion that if I really wanted to do something like that the answer is probably to buy a different car!

 

Though this is not what this thread started with...it became a discussion about exhausts/noise.

I have an ANSA exhaust in my 8 but its rattling when I shake it, so I presume glass pack is detached and maybe blocking passage a bit? I am in process of adding a supercharger so flow is important. I'd like engine noise to be Ferrari like but do not want more volume/sound.

I see Magnaflow has a dual in/dual out as well as Borla. I have used the Magnaflow on two turbo non-Ferrari cars so far and its great.

However, in this case it just occured to me that if I replace the Ansa with one of the above, there might be a flow issue. The mufflers inside are basically "X pipes" though straight-ish though. In the Mondial 8, and in the 308 I presume, one bank would feed one side of the muffler and the other bank would feed the other side of the muffler....isn't this bad because the flows will meet "in the middle" of the muffler? And while there are then two pipes to let the flow out, there might be some turbulence created in the middle and empirically restrict the flow. The flows would be "almost" pointing at each other in the middle....is this really bad?

Does it mean I have to somehow place two separate mufflers (single in/out)? -- or find a dual in/out muffler with NO cross pipe?

The Ansa solves this by essentially being two separate mufflers inside one box?

Thoughts?

Magnaflow/Borla dual in/out mufflers cost $250...plus some piping and welding is thus quite affordable.
(this Ferrari owner only has a piggy bank of quarters to save up to play )

 

The ANSA has a bulkhead in the middle that separates the 2 sides

I had a rattle in mine also. I cut it apart and found that the perforated 180 had broken loose.

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