webslinger

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Is it really that heavy, to hear the motor, or some other reason that escapes me?

Inquiring minds want to know.

-Doug

Tslick

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Think heat and your hoods finish.

DansSlk

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Its kinda heavy but not when you compare it to the weight of the hood so its not really a weight advantage removing it.

Its actually designed as sound proofing but to be honest so much vibration is transmitted to the hood anyways its all but redundant much more useful on the smaller engined cars, the V8 rumble will get past any insulation since its a very low frequency.

Because it is black and so close to the top of the engine it does act as a bit of a temp insulator on the 55 and unfortunately it keeps hot air floating about at airbox level and that serves to heat the intake air and as everybody knows the cooler the incoming air the better for a performance oriented engine.

We remove it on about 90% of the SLK55's we get here at the owners requests and in doing so your allowing the whole hood to act as a radiator and we have seen noticeable reduction in bay temps on the cars we have tested, its not going to hurt your paintwork and we have never had even one mention of it doing so, remember that the airbox itself sits atop the engine and if its bottom section does not feel the effects of the heat a steel hood wont mind at all and if you pop open the hood you will notice how close the chassis is to the headers and it survives without any paint damage.

Another common job is wrapping the headers up to keep the temp down that also heats them more and help with scavenging.

Only dis-advantage is it takes longer for the hood to cool down enough that you can clean it without it going all streaky.

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webslinger

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I'll be sure to add this to my list.

Thanks Dan!

Cold Shot

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Great reply Dan. I did not know this. Thanks!!

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2007 Black/Black SLK55 AMG (Green Filters, SmartTop V1, Eurolight Clear Side Markers, R170 Modded Antenna)
2007 Pewter/Black ML350
19xx White/Blonde Wife (Lmtd Edition Model)

bejak

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The insulation on the underside of the hood/bonnet on my 200 was only 1kg (2 lbs) with fasteners. I hoped for more when removing it.

In total I have reduced 57kg (127lbs) so far. Mostly at the rear. It's a bit more difficult to do weight reducing at the front. I'm thinking of replacing the battery for a smaller one and then relocating it into the trunk. It's a lot of available space there. The spare and the tools are gone.

DansSlk

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Mine was heavier than that when i weighed it not quite sure whats going on there.

I would leave the battery alone i agree its very heavy but the cars are very well balanced as is not just front and back but left and right if you move the battery it will screw that up.

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mtiede

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About the insulations purpose... My Dad worked for Owens Corning Fiberglas research for 35-40 years (don't remember exactly anymore, but it was a long time). He was a chemical engineer and had about 40 patents to his name. I don't think he came up with the idea of putting the insulation on the hood, but I vaguely recall when he first did it and it was one of the first cars to do so. My recollection was that it was for heat, not sound reasons. Of course, my recollections sometimes aren't so good But I am fairly certain that the original reason was for heat, not sound. Nowadays, maybe the purpose has changed.

DansSlk

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It probably was mate a lot of cars still use it for heat insulation but on the SLK its main job is sound proofing its even sold as such by MB.

You can normally tell whats for sound and whats for heat in the cars now by thickness.

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