Road Noise on 996

[Speedobird]

Hi - I'm looking for a consensus on how best to reduce the road noise coming into the cab. I searched under this topic and got fragmented answers. So here are a few questions if you will:

1. Is there something that can be done to shock towers or their base to reduce road noise transmitted through structure?

2. If we go with viscoelastic material like Dynamat, what would be the most effective areas to place this material?

3. Is there any other thoughts on how to reduce the road noise besides buying a quieter tires?

Hope someone has experience in this that they could share.

Thank you very much in advance, :renntech:

[CabC2]

I am curious about this too. Try this question in the main 996 forum, it will get answered faster.

Edited February 13, 2010 by CabC2

[GranburyChuck]

I went through, am going through, the same issue. The car is a 2000 996 Tip coupe and my daily driver car that I drive some back roads of north Texas as well as city in Fort Worth. The car originally came with stock suspension but PO put Eibach lowering springs on. Came with no name tires when I bought it. A lot of noise in the car. Switched to M030 springs on the original suspension. Rolling road noise was the same but harsh impacts less (because I wasn't bottoming the springs). Had to change out the tires and put some Yokahoma (don't remember model) all season tires. It was still noisy. Tires got shredded by a piece of metal and had to buy Falkens (don't remember model) on the spot. Still noisy. Finally, pulled out all of the interior in the rear and covered as much as I could with Dynamat Extreme (even inside rear inner fenderwell). Want to say it made a very slight difference, but wasn't fully satisfied. Dynamat recommends trunk, floor, doors, and roof to be covered. So I went to the doors next. Covered the outer and inner door skin with as much Dynamat as I could. Still noisy. Then put Dynamat all over the floor board, still noisy. Starting to notice that my tires are making one hell of a racket after only 5000 miles. Got DiscountTire to give me trade credit on the Falkens and I got Goodyear F1 All Season. Tires were way too noisy out of the box. I am beginning to think the cross chevron pattern was the culprit. Anyway, went about 5000 miles on those and said no way. Dumped those tires and put Sumitomo HTRZ III. Instantly much quieter and softer ride. I'm not saying that it's quiet but it is better than it was. So that brings me to current. When the weather warms I will be putting the remaining Dynamat I have on the roof panel and maybe double up some in the rear if I have leftover. Also, contemplating Dynamat Dynaliner as a sound absorber. Bottom line, this is not a BMW or Audi. Friends who get in the car don't understand how I can put up with that much noise and banging around. But hey, its a Porsche! By the way, I have 18" Porsche Sport Design rims. I believe the larger rim size (lower tire sidewall) also contributes to harshness and maybe noise level.

Oopps, forgot to add that after the Goodyear F1's and before the Sumitomos I needed to replace the suspension (>100k miles on original) and put the ROW M030 kit on, replacing ever part down to the nuts on the suspension. Don't do this, my impression is harsher suspension and may be contributing to some of my noise level.

[Speedobird]

I am curious about this too. Try this question in the main 996 forum, it will get answered faster.

Thanks for your suggestion. I thought I posted in 996 forum but I guess not.

[coolbubba]

Wheel bearings been replaced?

[Speedobird]

Wheel bearings been replaced?

Never thought about it. Does it make a noise similar to road noise? . I probably should check them out as it is coming close to 60K miles. Will report back when I get to it. Thank you very much.

[70Sixter]

Most tires I've had on all my vehicles got noisier with age. Especially when getting close to tread bars showing. And some tires are just noisy from the start. Tire Rack has some ratings/user feedback for noise and other characteristics.

[Stefan]

I've read that the most effective place to put sound deadener to reduce road noise is in the wheel well.

[rfauto]

I have found that tires made a huge difference on my 996 coupe. I purchased the car with Falken tires. They were no good. I replaced them with Continental Sportcontact 2. They were ok for like 1,000 miles and then got loud. A friend recommend the Michelin Pilot PS2. They are expensive and wear quickly but are the best yet.

[Orient Express]

+1 on the Michelins. They are by far the quietest high performance tires I have used on my Cab. It is very difficult to make a meaningful difference in road noise with the soft top simply because of the top's acoustic transparency.

I have found that the best way to make a significant dent in noise is to install the hardtop. it is like night and day with the hardtop on.