[Trueblue]

I noticed from many members under hood photos, that most do not have the factory heat/sound insulation intact.



The insulation is missing from my car as well, and I believe this contibuted to the premature fading of the paint on the hood.



Do most owners remove this material for a purpose (ie underhood temp reduction, clearance, etc), or just trash the material due to age seperation, with no intention of funding replacement?



I just ordered the replacement material and plan on installing as original.



Just curious......................



<img src="/forum/images/smilies/968/cool.gif" class="smilie" alt="" /> Rob

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[flash]

968s did not come with hood insulation - that was a 944 thing



insulation would very likely cause higher under hood temps - that is a very bad thing - i have yet to test it, but based on what i've measured so far, i won't likely be doing it, no matter how much i might like things to be quieter under there

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[ds968]

Had a liner, with it the temp was one full bar higher than it is now, and that was in regular traffic on a cold day. In heavy traffic and/or a hot day it was always near the redline. I ripped it out and as soon as I drove it without the liner ( on that same day, within an hour or two ) the indicator dropped down to the first mark, where it has stayed ever since.. In the heaviest bumper to bumper traffic and hot weather it may occasionally get past the second mark, but that's still a full bar+ of where it was with the liner, so I for one would never put a hoodliner back in again. Now, I have to say that the one I had in there was the old "tin foil" faced liner, which has the foil pointing down to the engine bay of course, another puzzling design / engineering choice <img src="/forum/images/smilies/968/blink.gif" class="smilie" alt="" /> . It's possible the newer versions, made of just foam or whatever other material they use may have technology which finds a way to eliminate retention of the heat in there, but I'm still a bit skeptical <img src="/forum/images/smilies/968/dry.gif" class="smilie" alt="" />

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[Cloud9...68]

Yeah, they've always struck me as a bad idea, too.

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[SILVY968]

well, I have a hood insulation covering on my cab.

I have not had any heat increase issues.

http://www.jageng.com/garage9/product_in...d85d604874

text from the company:

968 hood liners perfectly cut to fit the 968 (tested - check it out on www.968forums.com)



These heat shields will hold up much better than the OEM hood pad, keep the exterior of the hood cool and will not reflect engine heat back down toward your intake.



Made of 1/4 inch nitrile vinyl closed cell foam rubber, these hood liners will not absorb water or oil. Since the material is made for aircraft firewalls and bulkheads and is FAA approved for aircraft, its extremely light, about 11 ounces on average, are fire retardant and insulate against sound and heat.



You can wash the liner and simply hose it off and unlike the factory liner will not absorb water and resists mildew. Liners are available only in black.



Fire Retardant

Rot Resistant

Mildew Resistant

Sound Insulator

Heat Insulator

Oil Resistant

Chemical Resistant

Washable



The liners have a closed cell texture on one side and a smooth finish on the other. Most liners are symetrical and can be mounted with either side facing the engine. Easily installs with spray adhesive (such as 3M) available at most hardware stores.

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[flash]

silvy - what were your before and after under hood temps? i wasn't aware that you took any measurements



having done quite a bit of work with under hood air trimming, i can tell you for certain that it takes very little to change things under there - the hood definitely acts like a heat sink, and pulls heat away as the air passes over it - with the insulation there, i can't imagine it not getting in the way of that, resulting in higher temps under the hood, as the heat would have no escape



you will NOT see any of this in the coolant temp gauge on the 968, as the system would adjust to accommodate it in most climates - i can't speak to the 944



to be clear, there is no OEM hood pad for the 968, so i don't see how a comparison can be made there



the product is well made and obviously would quiet down engine noise - i just need to see temp readings before i go there, and i haven't popped for the pads yet to test them, and to my knowledge nobody has stuck sensors in there to see



you can get sensors really cheap though and answer the question for everybody - hint hint

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[Trueblue]

Thanks for your responses, I assumed the factory installed a liner on the 968, as the majority of high end cars have some type of insulation on the hood backside. Maybe Porsche engineering noted some heat retention issues during development, and felt it advantageous to let the hood conduct some heat away from engine bay.



I might give the installation a go and closely monitor the positive and negative aspects relative to the climate, and various driving conditions. I can easily remove it if things don't look good.



My engine installation is currently bone stock (exc. airbox mod), and seems to run on the cool side according to the heater-meter on the instrument panel.



Thanks again for all the information.

<img src="/forum/images/smilies/968/cool.gif" class="smilie" alt="" />

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[flash]

i have sensors here if you want to pop up and do a before/after test

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[Trueblue]

Thanks Flash, I might be able to scrounge up a few temperature data loggers, if not I'll take you up on your offer. Then perform before/after measurements.



<img src="/forum/images/smilies/968/cool.gif" class="smilie" alt="" /> Rob

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[ds968]

If you put one in, definitely go for the type Silvy 968 has, or similar.. I would caution everyone NOT to get the silver foil kind ( even if they're still sold anywhere nowadays ) because I can guarantee you the temps will increase significantly, and you won't need any fancy instruments to detect that, the guage needle will tell you right away !

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[Trueblue]

Thanks ds968, based on your experience I'll steer clear of the reflective foil (NASA polyrazmataz) type material.

<img src="/forum/images/smilies/968/cool.gif" class="smilie" alt="" /> Rob

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[flash]

any updates on underhood temps?

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[DayDreamer]

I'm very curious as to the results. I have the pads from Jager waiting to be installed for the last 3 years, just never got around to it. If I get to sooner than later, I'll try some temp tests.

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[flash]

i may end up ordering them, just so i can do the tests - they aren't expensive

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[Trueblue]

Flash,

The car is in the paint shop so have not had a chance to baseline temperature values yet. I have ordered the insulation and will install them after getting the initial data set.

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[bva]

Flash,

I have a set from Jager that was never installed. I'm willing to donate for your experiment. Can you wait 'till Ortega Run?

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[flash]

hmmm - i am thinking they might fit in the box you are going to receive today - i would be happy to pay for the shipping here if they do

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[Langley968]

I also had a set from Jager for about a year and a half and yesterday I finally had it installed. An upholstery place that my company does business with offered to do it for free. Turned out really good. I will post pictures tommorow.

I will also keep an eye on the temp guage to see if it makes any difference...

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[bva]

flash - shipped UPS yesterday; you should see it monday

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[flash]

langley - since the cooling system is thermostatically controlled, i seriously doubt you will see any change there - that doesn't mean there won't be changes that can affect things - i'll do testing this week

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