[Langley968]

Look forward to your feedback

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[Langley968]

Here is how my hood liner install turned out...



   



Drove 420+ miles this past weekend, checked under the hood a few times, and everything seemed great. Then again, we live in the Pacific Northwest, where a "nice summer day" is not NEAR as hot as some of the temperatures some of you guys have to put up with ... <img src="/forum/images/smilies/968/cool.gif" class="smilie" alt="" />

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[flash]

i have the liners here now - working on a temporary suspension method so i can conduct the test - i have 3 sensors i can place in different areas under the hood, and see what the temps are

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[flash]

finally got to start on this



sensors mounted - will be driving around and establishing a "no liner" baseline - then will install liners and check against the baseline



should have results before the weekend

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[flash]

gauges in place ready for the test in the morning



   

   

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[Cloud9...68]

Langley-



Now that you've driven with the liners for awhile, is there a discernible reduction in noise level? These engines do make quite a bit of noise that I would't put in the category of "pleasant," so I'm curious as to the impact of the liners on the aural experience of driving the car.

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[SILVY968]

topend clatter is lower which results in a lower tone from the engine.

more better!

Brian

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[Cloud9...68]

Ah, that "sounds" good. Clatter is bad, and this engine sure produces plenty of it.



This underscores a really cool thing about these cars. Starting with the basic car, you can either got to the "max performance" end of the spectrum and replace all the rubber bushings with solid/spherical, add stiffer springs, a lightweight flywheel, take a bunch of weight out of the car, and do various engine mods, or, on the other extreme, there's a lot you can do to make the car more comfortable and pleasant to drive on the street, like putting Dynamax everywhere you can reach, the hood liners, a killer stereo, etc. Just depends on your personal taste. Or, you could have one of each!

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[flash]

okay - initial results are in - i'll be doing more testing, but i think i have some impressions



definitely reduces underhood noise, particularly sitting still - seems to quiet things down while driving too, though that may have been wishful thinking



temps seem to be as i expected - all sensors rose about 7 degrees with the pads in place while driving



however, there is an odd heat soak/recovery issue - heat soak seems SLOWER with the pads in place, but recovery seems FASTER with them not there - that one doesn't make sense to me, unless they actually affect the air flow



more testing required

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[flash]

ok - i had a chance to spend some time on this today



it is confirmed that the hood insulation pads cause the under hood temps to rise about 7-8 degrees at all points across the engine bay, both driving and sitting still - heat soak goes up about the same amount when sitting still with the engine off - it also causes the hood temps to rise about half that much both driving and sitting still



but, that's not the whole story



the insulation appears to change the airflow under the hood as well - this is both a good and bad thing



the bad thing - temps rise - this costs power - you are losing about 1-1.5hp for the temp rise - not a lot, but definitely there, and definitely would affect throttle response - it also seems that the airflow under the hood is slowed down, which means a slower recovery to lower temps after sitting still



the good thing - since it seems that it is slowing down the airflow under the hood, it also causes a slower temp response - while this is not desirable on cool down, it does certainly mean that it takes longer to heat up, as well as means that the under hood temps are more consistent - this would be a plus when it comes to materials longevity



the other thing i don't like about this product is that the material is extremely easy to damage - it shows mars and marks very easily, and once dented or creased, it does not recover fully



but it definitely quiets things down - as an example, the supercharger noise all but completely disappears



so, to sum it up, i cannot recommend against this product, even though it has its downsides - personally i'm still on the fence, as i really like a clean engine bay, and i'm not sure i could have that with this product (unlike being able to wax the hood) but the noise dampening may push me over the top and into using this or something like it

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[Ab54666]

Interesting results Flash, couple of thoughts ;



1. Is there a thermostat available that opens earlier? I remember from <acronym title='model year'>MY</acronym> Mini days there were more than one thermostat available, opening at 74, 82 & 8 Degrees. If so that may help keep temp's down.

2. I know a few 944 racers who use Redline Waterwetter in the coolant as it helps keep the coolant temperature down to an extent, according to Redline by up to 20 degrees.

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[flash]

coolant temp is not the issue, and not nearly the hottest thing in the engine bay - the exhaust generates far more heat than the coolant - reducing coolant temp, even 20 degrees, would have a minimal effect on under hood temps

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[Lim Yong]

Hi Flash,

great work on this.I am thinking, based on the info, that the insulation can be trimmed to cover part of the hood? maybe over the exhaust only so that interruption to airflow is minimized and still have some insulation benefits......ThanksAlso, I fond that the hottest (by touch) area of the hood is right over the front of the engine, where the cap/rotor area.So maybe a partial insulation at that area and over the exhaust may make some difference?

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[flash]

that hot spot is due to the coolant neck being so close to the hood - it's an anomaly in the engine bay, and the only area where the coolant actually translates to a hot spot that can be read



but, you may have an idea there with doing only the one side, but i would caution against doing that on an engine without an exhaust heat shield, as without it that is the hot side, and it may slow the airflow down too much to effectively cool things down - with the heat shield in place, the heat is held back, so it isn't an issue, and the intake actually becomes the hot side



i'm not likely to mess with this anymore, and will just make a decision if and when i find a material that doesn't damage so easily, and also is easily cleaned

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[Lim Yong]

Kool..... I have a tip so already have a heat shield, though I didn't know it at the time and wanted to buy the heat shield you developed.



Wondering if an additional shield there and some (shaped) insulation will help.....I actually would like to reduce under hood temp.

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[flash]

the best way to do that is to make sure you have all of the underbody panels that are supposed to be there - this ensures proper airflow and negative pressure



then, you can steam clean the engine and keep it clean - that will help a lot



after that, you can start working on blocking heat from getting into the bay by means of things like the shield - you could add thermal barier material to the one you have, or you could scab on an extension, and add the material to that



after that, you have to start getting crazy like i did, and add pieces to redirect the flow - it worked for me, and in the end, my underhood driving temps are only about 10-20 degrees over ambient - it wasn't easy though, and i'm still not done - i need to work on cooling off my shifter

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[Lim Yong]

I covered two of the four (rectangular) openings that is on the second undertray, the tow other ones. My thinking is that will provide more air going to the sidess (exhaust area and intake plenum), and also push more air out where the oil baffles are located in the air stream.



Of course, I have no idea whether this works or makes sense. Anyway, apologies for the thread jack...Thanks

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