Installed new PP sound mat...
 

If you're thinking of ordering a new engine compartment sound mat to replace an old, disintegrating factory original, there's a few threads here that you should take the time to search out and read. I was convinced that I neaded to wait until such a time that the engine needed to be dropped, but the interior roar was becoming one of those annoying itches that could no longer be endured, lest I find myself in the State Hospital for having flipped out. Neither my regular Porsche expert, nor the dealer would tackle the job without dropping the engine, and the cost (for obvious reasons) were prohibitive. Having more time than money, I decided to tackle it myself after reading a thread posted here which said it could be done with the engine in place. Whoever it was who posted his story, I wish to thank. Here are some pics:

Install completed... Removing the air filter box cover was the most time-consuming, and knuckle-scraping aspect to the whole job. I darned near gave up on it, and figured that my mechanic really earned his money whenever I'd pay him to change the filter. Those rear clips are a B to unclip, and even tougher to reclip.
http://forums.pelicanparts.com/uploa...1341172019.jpg

After removing the cover, it was relatively easy to remove the box itself. Not wanting to futz with removing whatever vacuum line was attached to the air intake box, I left it in and worked around it.

http://forums.pelicanparts.com/uploa...1341172555.jpg

Noting that the pad needed to be jammed behind the cruise control servo, and it needed to be pulled forward, the challenge of getting hands into a position to loosen its two mounting bolts mandated clearing the way. After removing the ductwork and blower, getting the electrical connectors for the various sensors was needed. They swung out of the way nicely. This gave relatively easy access to the two 8mm mounting bolts.

http://forums.pelicanparts.com/uploa...1341173014.jpg


After jamming and positioning the bottom of the new mat as best I could, tucking it behing the CC servo, and the cross-compartment a/c hoses at the bottom, it was held into place rather nicely. Folding down the top as much as possible, and aiming the adhesive can's spray nozzle with care, an adequate amount of cement could be applied to both the underside and rear metal, as well as the foam itself. After drying for 10 minutes the mat adhered well enough, and positioning it under the clip tabs held it without sags. Refitting the parts which were moved to get enough hand room to work was just a reverse of the removal, and once again, the real B was the bleeping air-filter box cover. If you're an old hand at that, the rest is a one hour job. If you're a purist, and need every bit of old gorilla-snot spray glue removed, well, it ain't so simple.

http://forums.pelicanparts.com/uploa...1341173767.jpg

next time i'm just using magnets, no glue, the life of these mats is short

Yeah, I saw the magnet trick mentioned on one of the threads, but it made me wonder if the vibration dampening effect (and thus the sound muting) of the direct bonding of foam to metal would be compromised. I'm extremely pleased with the results of my effort, and ecstatic over the fact that PP's price for the exact same mat sold by the dealership's parts department was 50% cheaper.

Also worth mentioning is a thread I saw about tricks to R&R the air filter box cover. Placing a plastic tiewrap around the hoop of the rear clips made finding them by Braille and moving them into position in order to clamp them was a stroke of someone's genius, and worked very well!

I did my mat with magnets about one year ago, I can not tell any difference in cabin sound when compared to my friends cars who glued it in. It is easy and looks like it was glued in. So far so good

Could also try velcro instead of the magnets, need to do mine, but everything is on hold until I move, so I will look at both those options after I get to the new place.

Buckeye, can you elaborate on the magnet trick. i am getting ready to do mine and would prefer something that is easily replaceable. do you use the psa magnets?

What a coincidence! I just ordered sound pads and saw this thread. Magnets or velcros would be a good alternative. But the process of installing it without dropping the engine looks like a PITA.

This is helpful. Keep them coming!

I purchased my magnets at Lowes, they are small round magnets maybe an inch in diameter. I glued 20-25 of them on the back of the pad. I used a two part glue that I also purchased at Lowes. I allowed them to dry overnight, I don't know if that is necessary but it made me feel better. I glued them around the edge of the mat, do not place them too close to the top of the mat or you will be able to see them when you open your hood. I also glued a couple of rows of them across the center of the mat. The next morning I removed the air filter cover (3.2 motor) and put the mat in place. I will take you 15 minutes or so to work the mat in place. Replace the air filter cover and you are done. From start to finish it takes 30 minutes

Even if my motor was out of my car this is the method I would use. You do not have to clean off the old glue and it looks and sounds like it came from the factory. When this mat starts to go bad I will rip it out and put in a new one

Porsche should have designed it this way

Oh, how did I miss this one! I still have scrapes on my arm from an airbox r/r last week. Zip ties are the new bailing wire.

J

Excellent write-up!! I plan on doing mine this weekend.

Two questions -

Which adhesive did you use?

Do I need to go crazy on removing the old glue?

Thanks in advance.

Christopher, I wouldn't (and didn't) mess with removing the old glue, mainly because getting arms in there to use a solvent/stripper was near impossible, and likewise to wield a scraper. I used 3M Super 90 Hi Strength spray adhesive, though there's another 3M product that's touted as for use in high heat areas. Essentially, if you can get the horizontal surface to adhere nicely you're home free. The vertical surface along the back firewall pretty much tucks in and stays in place when wedged behind the hoses, CC servo, etc.

I wish I had thought of the magnet business. I'm wondering if the self=sticky sheets of plastic magnet material they use on display boards, etc would work well. On the other hand, if this new mat lasts another 27 years before disintegrating, I'm not going to have to worry about replacing it myself... I'll be dead.

JQ911, you're right, it was a PITA, but not all THAT tough!

Don

Looks good. I replaced my filter yesterday in conjunction with a valve adjustment. The tie wrap trick on the air cleaner cover clips works well. I have smallish hands and can get them back there (kind of) without scraping off ALL my skin. Having the tie wraps on the clips really makes the act of snapping them closed much easier.

1. 3m makes a good adhesive

2. no

I replaced the sound mat on my '86 Cab in January after I bought the car. I also used 3M glue and didn't bother too much getting the old glue off. I think the car is much more quiet inside with the new mat.

Actually, they make a zillion of them. Make sure you pick one that handles temperatures in the expected range. Not all 3m adhesives do well with heat. In fact, the one that seems to get suggested the most for interior use performs poorly, as it's designed for not-very-high temperatures.

Myself, I use a good solvent-based contact cement, not something out of a spray can.

JR

very true - a search on one of the thousands of sound pad threads will turn up some likely candidates for the exact 3M adhesive to use

I cleaned/detailed the engine a bit over the weekend using simple green. Took out the sound mat as well which disintegrated as I pulled it out, lols!

Hope I get the mats right but this would entail alot of man hours...wish me luck!

I used 3M scotch grip rubber and gasket adhesive # 847. In a Tube.
It will need to be scraped off!