anyone have any words of wisdom on dynmat installs?

mjshira · 08-18-2003, 05:58 PM

I am getting ready to install some before installing the RS carpet kit I have. Anyone out there done this before?

Randy Webb · 08-18-2003, 06:28 PM

Well, let's think about this for a minute -- you're putting in a light wt. carpet set -- to save wt., right? Why put in heavy sound deadener? It doesn't make sense.

Instead try a light wt. sound treatment. I haven't tried it yet, but my reearch on the topic led me to:
http://www.quietcoat.com/html/technology_overview.html

Search for threads on this...

mjshira · 08-18-2003, 06:33 PM

thanks.

911pcars · 08-18-2003, 06:34 PM

I used an equivalent product from JC Whitney (about $30 for a 32x54" sheet). They call it Sound/Vibration Dampening Sheets. You'll need 2 sheets for the the front and rear floor area. I used smaller pieces for flat areas of the door, tunnel and trunk areas to help dampen noise.

Dynamat is good too, but it's quite a bit more expensive. Since this is asphalt-based, excess weight is the result if used in large quantities. I saw a 525 audio-prepped Bimmer with the entire front cowling/bulkhead/wheel wells covered with Dynamat. Owner claimed about 300 lbs. added due to the Dynamat.

There might be newer, more effective and lighter materials for this purpose.

Sherwood Lee
http://members.rennlist.org/911pcars

RoninLB · 08-18-2003, 08:48 PM

there are a few flavors of Dynamat.. I have used it and "BrownBread? I always use a hair dryer to warm it and the steel up after cleaning the steel with touline. sometimes 2 layers make a big difference.. I do a hand slam on the steel after the first layer to find any smaller areas of the big area that will continue to produce sympathetic harmonics.. the deadner will deaden the tin can original sound and make your muffler and engine sound "cleaner" IMO.. and I'm sure you know the relationship of weight to HP to performance............Ron

Randy Webb · 08-18-2003, 10:04 PM

Post your impressions after you make your decision.

I have Dyna mat in my '75 -- quite a few pounds of it. The door feels like a MB and not the new cheapo one either. But the car is a lot heavier. In my book, when you own a Porsche, you want light wt.

Dave Ploss · 08-19-2003, 04:27 AM

I put dynamat on the interior and it made a dramatic difference in the noise level. My wife was amazed at how much quieter it is.

It is heavy but I'm not going to track my car and it has plenty of performance for me. It just made the car more enjoyable to drive.

The only downside, for me, is that now I hear other noises that I couldn't hear befoe and I'm wondering what they are.

I'm happy with it. I agree with Ron, warm up the dynamat and metal and it goes in very easily.

Dave

derek murray · derek murray's Garage

Fellow Pelican RallyJon has a great website that describes his install of an RS carpet set and sound dampening material.

http://www.rallystuff.com/pcar_interior.html

If you decide to go with Dynamat, checkout its competitor, BrownBread first... its cheaper and supposedly better.

http://www.b-quiet.com/

Good Luck

mjshira · 08-19-2003, 08:09 AM

thanks guys for all your thoughts. my car is a 69 911E with all 86 running gear. I am running RS America seats (are they lighter?) and I have taken as much weight out of the car as I could. I think that the approach I will take is dynmat then lcomp from b-quiet. The 3.2 in the early car with a 7:31 915 gives me fairly good performance. I am hoping that 20 pounds of sound deadner won't hurt that performance. But since I plan to go to a 993 euro next year I going with near term street driving enjoyment. Last year when my girlfriend and I went to Indy for the F1 race I had to listen her asking "why is it so loud"? ;-) But I got my revenge when she was asleep during the night on the ride back and I was crusing @ 120! Anyway, sorry for the long post. I'll put some pics up when I get it done. Oh I also plan to use magnet paints product to seal the interior. --James

88911coupe · 08-19-2003, 08:49 AM

I have read (here I believe) that there's a roofing material that is used around sky lights that's very sticky rubberized stuff on one side that works VERY well for this application and it's a fraction of the cost. Supposedly the only problem is that it's sold in large rolls. Maybe if you have a roofer doing work in your neighborhood...
Just a suggestion.

mjshira · 08-19-2003, 09:10 AM

thanks. I'd check that out BUT :-) I already have all the materials.

dotorg · 08-19-2003, 09:23 AM

The Lcomp that B-Quiet sells is fantastic, as well. Before putting the RS carpet set in my car (which is finally back on the road today, woooo!), I put some generic knock-off dynamat on the interior side of the rear wheel well humps, because the stock sound deadening was removed. The P.O. had put Dynamat on the rear deck, and floors, and small pieces on the seat bottoms. I put 16 sq/ft of Lcomp (two 2x4' sheets, 8lbs each) in the car covering the rear deck, the rear seat backs and bottoms, and then installed the carpet over everything. Car makes a very nice mean growl now, but I can have a conversation comfortably in the car. Its almost quiet with the windows up.

Expensive, but worth it if you're doing the RS set for looks more than weight (its not like the 5-10lbs you save with the RS kit is worth it in anything but a track car, and WTF do you have carpet in a race car for?).

dotorg · 08-19-2003, 09:25 AM

Quote:

Originally posted by 88911coupe
I have read (here I believe) that there's a roofing material that is used around sky lights that's very sticky rubberized stuff on one side that works VERY well for this application and it's a fraction of the cost. Supposedly the only problem is that it's sold in large rolls. Maybe if you have a roofer doing work in your neighborhood...
Just a suggestion.

Yeah thats a big "secret" in the car audio scene -- ice guard sheets are $70 for like 400 square feet, and works just as well as dynamat. I've used it in three or four cars in the past, and would've used it in my 911 if the P.O. hadn't already put dynamat in it. Its got a sandy textured top surface, which can be messy if you don't take some time and brush off all the loose grit.

mjshira · 08-19-2003, 09:34 AM

thanks for the posts. I am hoping that it'll take the edge off the noise level. I have new sound mat in the engine bay also (thanks to Taso over at RPM) which helps. When I install the RS parcel shelf that should also cut some of the noise down.

cowtown · 08-19-2003, 09:52 AM

Quote:

Originally posted by dotorg
Yeah thats a big "secret" in the car audio scene -- ice guard sheets are $70 for like 400 square feet, and works just as well as dynamat. I've used it in three or four cars in the past, and would've used it in my 911 if the P.O. hadn't already put dynamat in it. Its got a sandy textured top surface, which can be messy if you don't take some time and brush off all the loose grit.

There is also a roofing-related material called "Peel-and-Seal" that is supposed to be equivalent to some of the sound-deadening products. It's at Lowe's in 6" wide rolls. I think they are 15' or so in length. Cost is $15 and each roll weighs about 5 lb. It's a very adhesive tar with a foil backing. You pull off a waxpaper sheet and stick it like a normal sticker, and it will never come off.

I put 2 rolls of this stuff in the back seat/engine deck area after doing POR15 and it made a huge difference in the "tin-can" factor. I've never used Dynamat, so I can't compare it, but I am satisfied with the cost/weight/noise tradeoff. I just could not pay that much for Dynamat, although I know it's good.

derek murray · derek murray's Garage

cowtown and dotorg...

does the ice guard or peel and seal "smell up" the car at all?

dotorg · 08-19-2003, 10:04 AM

Nope, its basically the same stuff that dynamat is, minus the branding.

CHILI · CHILI's Garage

Definitely get the little roller wheel thingy! You can also use the end of the handle in tight radius places. I've done two cars. One without the tool and one with. Much easier with it. It's only about $10.

Pete000 · 08-19-2003, 04:07 PM

It does work well, but a couple of rolls are not very light and it will take a couple rolls to do your car. If you are into hearing the stereo and not the engine go for it. I would pass in a 911.

cowtown · 08-19-2003, 04:21 PM

Quote:

Originally posted by Pete000
It does work well, but a couple of rolls are not very light and it will take a couple rolls to do your car. If you are into hearing the stereo and not the engine go for it. I would pass in a 911.

I totally agree with you that it's extra weight, and I cringed while putting it in...after all, I spent two days stripping the tar up off my floor and doing POR15. BUT...it was so loud that it was unpleasant to drive. When you get over a certain noise level, it's just not fun anymore.