Engine Pad - Installed! - Page 3

84porsche9113.2 · 06:42 PM

Quote:

Originally Posted by gsmith660

I don't think the inside of the engine bay looks bad.

Actually, that made me think of another reason I haven't put back the pad. I think I did so once (after I bought the car), and in a matter of years it just disintegrated again. Doesn't seem like the foam is that durable, from my experience, and with the high heat in the bay, I wouldn't expect any different.

Anyone have any idea "on average" how long these things last?

So anyway, I figured by leaving it out I'm not loosing any performance, plus it is a lower cost/lower maintenance solution because I'd eventually be looking at replacing the thing every couple years or so?? In other words I'm not sure I want to be spending several hours or more and $60-$85 bucks (depending on s&h costs) every couple years to replace the pad, especially when I don't really notice it's there much. A pure cost/benefit analysis, based on my preferences.

If it was a lot more durable and/or would last the lifetime of the car, I probably would replace it though.....

rusnak · 03-04-2008, 10:49 AM

Actually the durability is a secondary concern to managing the heat.

Noise is not a concern for almost anyone here it seems.

My question is does the soundpad or the options such as dynamat actually act as a heat sink and prolong the cooldown period? We all know that the engine gets really hot. On 105F+ days in the summer I park with the engine lid open to let the heat out. I'm somewhat concerned with the rapid cooling and the stresses on things like head studs, but far less than the effect of such high heat on rubber intake and fuel line parts, not to mention plastic FI parts.

I wonder if a heat resistant cloth or fabric material might be the best option.

RWebb · RWebb's Garage

The thermal capacity of foam is extremely small. It also acts to _insulate_ heat. So, no matter what you mean by the heat sink effect, it will be negligible.

The foam pad will last many years. You can put some RTV along the edge if you are worried about that.

On other item - a friend didn't install one b/c he thinks that it will trap any leaking water (which caused a lot of rust on his early car). Of course, you'd have to park outside in a lot of rain and have rear windscreen leakage for that to be a problem. Also, one could use a pad made of ensolite or other closed cell foam - they will not absorb water like open cell foams do.

rusnak · 03-04-2008, 10:59 AM

I was looking at rubberized sound pads and rejected them because they can stay hot for hours. Foam does sound like a good short term solution but I'm not a short term 911 owner.

I wonder what light aircraft use

rusnak · 03-04-2008, 11:03 AM

omg, hey

I answered my own question. Check this out:http://aircraftspruce.com/menus/ap/baffling.html

porschefool · porschefool's Garage

Other than appearance, what's the point of this stuff?
Is someone actually sitting in the back seat, getting annoyed by the sound or heat?
When I finally do my engine drop, I think I'll go the scrape-n-paint route.
Had lots of fun vacuuming that disintegrating crap out of the top of the CIS stuff...

RWebb · RWebb's Garage

To each his own.

Many dislike the noise profile of the bare metal.

rusnak · 03-04-2008, 12:51 PM

it's the heat against vinyl, carpet, and speakers that I'm concerned with

RWebb · RWebb's Garage

use the foam unless the Aircraft Spruce pads have greater insulation values

I Emailed them for info - they may not know.

84porsche9113.2 · 06:23 PM

Quote:

Originally Posted by rusnak

Actually the durability is a secondary concern to managing the heat.

Noise is not a concern for almost anyone here it seems.

Correct me if I am wrong but I thought the whole point of this thread (up until my posting anyway) seemed to indicate that the reasons everyone wanted to put in a new pad (or replace a deteriorating one) was for the sound difference (and/or possibly looks)?

I think if anything was clear from this thread, that much was...

This is the first time I've heard about heat being an issue. I also run a child seat in the back and I haven't been too concerned because between the firewall there is a pretty thick seat backrest, plus I've never noticed it being hot or anything back there.

My first thought, like RWebb, when I saw this is that foam does not seem to be a very good insulator of heat, but I suppose it is better than nothing. I would think if you parked your car out in the sun all day, every day, you'd probably do more damage to your vinyl and speakers than any heat from the engine compartment unless you are constantly reaching relaly high temperatures in the back. This is evident by the fact that the seatbacks and carpet are still original, though i've had to replace the rear shelf speakers and rear shelf vinyl from sun damage when i bought the car. I would think if heat was a concern (i've been running without the pad for over 8 years or so) that I would've have had problems with the vinyl or speakers since then, but I haven't.

Also, I think the higher the heat obviously the quicker the foam would deteriorate. And if the heat is kept in the engine obviously this would increase the engine temps.

If heat management is really an issue (to protect the interior) then I still think the pad should be made to withstand it better so it does not have to be replaced so frequently.

richde · 03-05-2008, 07:34 AM

Quote:

Originally Posted by 84porsche9113.2

Correct me if I am wrong but I thought the whole point of this thread (up until my posting anyway) seemed to indicate that the reasons everyone wanted to put in a new pad (or replace a deteriorating one) was for the sound difference (and/or possibly looks)?

I think if anything was clear from this thread, that much was...

This is the first time I've heard about heat being an issue. I also run a child seat in the back and I haven't been too concerned because between the firewall there is a pretty thick seat backrest, plus I've never noticed it being hot or anything back there.

My first thought, like RWebb, when I saw this is that foam does not seem to be a very good insulator of heat, but I suppose it is better than nothing. I would think if you parked your car out in the sun all day, every day, you'd probably do more damage to your vinyl and speakers than any heat from the engine compartment unless you are constantly reaching relaly high temperatures in the back. This is evident by the fact that the seatbacks and carpet are still original, though i've had to replace the rear shelf speakers and rear shelf vinyl from sun damage when i bought the car. I would think if heat was a concern (i've been running without the pad for over 8 years or so) that I would've have had problems with the vinyl or speakers since then, but I haven't.

Also, I think the higher the heat obviously the quicker the foam would deteriorate. And if the heat is kept in the engine obviously this would increase the engine temps.

If heat management is really an issue (to protect the interior) then I still think the pad should be made to withstand it better so it does not have to be replaced so frequently.

Um, it's a SOUND pad, not a heat pad.

Where does the majority of heat from a 911 engine go? The foam ones break down because....they're foam.

84porsche9113.2 · 10:11 AM

Quote:

Originally Posted by richde

Um, it's a SOUND pad, not a heat pad.

Where does the majority of heat from a 911 engine go? The foam ones break down because....they're foam.

My thoughts exactly! I wish I could have been this precise and economical with my choice of words.

Are there more durable (and good looking), effecient sound pad designs than the oem ones?

I agree that the oem looks a lot better than the silver foil look one on ebay (looks like someone plastered their compartment with tin foil), but I just don't like the low durability of the oem foam one (my opinion).

Lookswise, I personally feel the bare engine compartment looks pretty good (mine looks to be some sort of factory undercoating or finish, like the rest of the underbody), so I see no need to paint even. Between the look of the OEM sound pad and without it, I see no difference, and I'm usually very particular and have high standards about how things look.

On the other hand I wouldn't mind having a little sound reduction if the sound profile sounds better than without (someone mentioned it sounds more like a vw and less like a porsche without the pad), but again, my concern is durability of the pad. If they made a good-looking pad that helped the engine sound better and was more durable, I'd be willing to try it.

rusnak · 03-05-2008, 11:14 AM

what is the best insulation? air.

what is foam mostly made of? air.

RWebb · RWebb's Garage

Exactly - we should say _still_ air.

"My first thought, like RWebb, when I saw this is that foam does not seem to be a very good insulator of heat..."
- I hope I didn't give this impression. Foams are excellent heat insulators. Even a metal foam (which has higher conduction of heat along the edges of the little bubbles since they are metal) is a good insulator.

Sound:
I've ridden in a friend's MFI 2.5L car which has NO pad; and in mine (3.2L & carbs) which does. I like the sound profile in my car best. His sounds kinda "rattly" - in other words, I suspect that higher frequencies are attenuated more by the foam pad than are lower freq.s - as would be expected.

Longevity:
I dunno where this is coming from. Who has had a pad break down in less than 5 years? In less than 10?

My understanding is that they last quite a while.

But again, to each his own.

If I were going to leave the pad out in a dark colored car, then instead of the dark body color (or the "bottomless-pit-but-period-correct-black that some use) I would paint the engine comp. a nice reflective metallic light gray or silver -- just like the pic above.

Just be clear on what you're doing & why you're doing it.

You could leave the pad out - paint - then if you don't like it, it is easy on some of the older cars to put it in w/o dropping the motor, or only partially doing so.

84porsche9113.2 · 02:06 PM

[QUOTE=RWebb;3809734]Exactly - we should say _still_ air.
Longevity:
I dunno where this is coming from. Who has had a pad break down in less than 5 years? In less than 10?
QUOTE]

I personally have had a pad break down in less than 5 years and this was a weekend driven car. I bought the car in 1997 or so, the pad was broken down at the time and I replaced it with new, then later, I had to replace the pad in maybe 3-4 years. Mind you, it was not "completely broken down", but it was very stiff and brittle and some of the glue seemed had come off. If I remember correctly, it was still completely intact and physically still looked good. I was just concerned because part of the pad was falling off and came unglued at certain areas only (I did use the recommended 3M adhesive for the original job). Also, it would have been impossible to reglue that same pad back in because it was so brittle and the glue that was still working to hold the foam to the car was stronger than the integrity of the foam pad. So rather than redoing the whole job, I took it out and left it out.

Sorry, if I misread or misunderstood your comment. I am not disputing whether or not foam is a good insulator of heat. It probably very may well be. However, whether or not foam is a "good heat insulator" seems to be irrelevant to the original point that the poster made which contrasts with the previous posts in this thread. In his original post, he stated that the real issue in these pads was heat management and that everyone is okay with the sound without one. On the other hand, my contention (and those of others apparently), is that it seems these pads are advertised as a "Sound pad" (check the ebay listings), and not a "heat pad". If you ask me, the pad was designed with sound primarily in mind, and heat as a secondary concern, not the other way around. But then again, I'm not a porsche engineer so I could be wrong. I am just saying that this seems to be the common conception that these engine pads are "sound pads" and not "heat pads". I never heard that "heat management" was the primary issue with these pads until the referenced poster made his post.

So what is it's INTENDED design then? Regardless of whether foam is in fact a good insulator of heat, it probably is a good insulator of sound as well. So even if it can be used to manage heat, the question remains, is it intended primiarily as a sound pad or heat pad? The reason the answer is important is because it affects people's decisions on WHY they should choose to replace the pad or leave it out...

rusnak · 03-05-2008, 12:04 PM

title of this thread: "engine pad....."

call it whatever you want, my gawsh. Unless you teach grades K1-12 what does it matter to you what other people call things?

There are two functions performed by these things: insulate from heat transfer, and block sound transmissions.

My dad has an original 1978 911SC. Yes, the "engine pad" is brittle, but I don't think he goes and pulls on it either. In my case the PO let the pad fall down onto the top of the motor. I had no choice but to pull it out. I wonder, as is natural, if there is something that will work better and last longer.

As Randy says, to each his own. If you're happy with your engine pad, and you want to call it an "engine french toast stick", then go for it, be happy.

RWebb · RWebb's Garage

I sure wouldn't go by what ebay sellers use as a description(!)

rusnak - I dunno if there is anything better. To me better, would be lighter, with a better noise transmission profile (maybe lower, but maybe not), 3rd, better heat insulation, 4th, longer lived, and 5th, cheaper! We can even add more functions to that too.

Certainly, an aerogel would be fun if some fo the above were no object... or maybe ceramic tiles off the space shuttle - I bet there are a few lying around the Florida swamps below the flight path...

Anyway, I'll post if Aricraft Spruce responds re their two pads. I am looking for some interior padding.

84porsche9113.2 · 12:54 PM

Quote:

Originally Posted by RWebb

I sure wouldn't go by what ebay sellers use as a description(!)

neither would I completely. but I also think if it was a heat pad they would list it as a "heat pad" and not a "sound pad", otherwise they wouldn't be able to find any buyers. It just shows what their conception of it (and of the tons of people looking for one and buying one) is.

anyway, you seem very knowledgable about this issue. it would help me if you answered my question.

do you know if the pad was designed primarily for heat or sound, or do you not?

84porsche9113.2 · 02:11 PM

Quote:

Originally Posted by rusnak

Yes, the "engine pad" is brittle, but I don't think he goes and pulls on it either. In my case the PO let the pad fall down onto the top of the motor. I had no choice but to pull it out. I wonder, as is natural, if there is something that will work better and last longer.

At least we agree on this much.

Yes, it is an engine pad but the thing is if heat management should be a BIG concern on mine, then I would reconsider my reasons for not putting it back in. Previous to your post, heat management never crossed my mind...

The issue isn't whether I teach K-12 or whether I care about what people call things. I just want to know by leaving it out am I missing something that could be harming my car (via heat) as you seem to suggest? (because before I thought all I was getting was a louder engine by leaving it out).

By the way, what is with this "engine french toast stick" comment? You seem to suggest that something is what it is regardless of what people call it. I agree. But on the other hand, I also think that language does serve some kind of purpose, and that being the case, USUALLY people TRY TO give ACCURATE descriptive names for things, not false ones.

84porsche9113.2 · 01:10 PM

Quote:

Originally Posted by RWebb

I sure wouldn't go by what ebay sellers use as a description(!)

haha.

I couldn't resist this one. If you wouldn't go by what ebay sellers use, would you go by what pelican parts porsche store uses as a description? We are on a pelican parts BBS after all....

Pelican parts lists the part as "Engine Compartment Sound Mat".

http://www.pelicanparts.com/cgi-bin/ksearch/PEL_search.cgi?command=show_part_page&please_wait=N&make=POR&model=911M&section=MISCLL&page=14&bookmark=&part_number=PEL-APBZ-ESPU

By the way, the description of the part also states:

"Is the sound from your 911 engine making a racket? Replace your missing sound pad and keep the engine noise down. Please Note: The material of the sound mat has been updated and is now made of the same lighter weight material used on current late model Porsches."

It says absolutely NOTHING about heat.