I would love to see a clear cover for the airbox in the M5. The inside of it is very cool. I have no idea how long it would stay clean on the inside, but I would think it would be OK given that the incoming air is filtered.
Can anyone tell me if there are clear materials that are up to the challenges of forming and withstanding the heat?
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Polycarbonate is a pretty good choice for an airbox cover. It's clear, and holds up good to heat. To have an airbox made from polycarbonate would require someone to mold a box for you out of polycarbonate. They would have to make a mold from the existing box, which is costly$$, and then make polycarbonate air boxes from that. The cheapest molds and molding operations are done through either Rotational Molding or Vaccuum Forming. You'll have to do some research to find out which one is cheaper, but either way you go, it's going to cost some money.
Bimmeup - thanks - good info. I was thinking about just the cover - makes it really simple to mold, as well as for customers to install (if I decided to produce a bunch.)
Louv - I do know TAP - I've used them many times. Good suggestion.
I don't have any time to work on this until Sept, but I'm thinking about it....
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'00 A6 4.2 - doesn't deserve a web page
Cyrolon sheet is a tough and highly impact-resistant polycarbonate material. It is light weight with exceptional clarity and light transmission properties. Since it is difficult to break, it is useful wherever safety, security, or impact-resistance is important.
Cyrolon will expand and contract with temperature changes, but will not shrink with age. Some shrinkage occurs when it is heated to forming temperature, but postforming stability is excellent.
Cyrolon is resistant to many chemicals including highly concentrated mineral acids, many organic acids, neutral and acid salt solutions, greases, and oils, saturated aliphatic and cycloaliphatic hydrocarbons, and alcohol (except methanol).
From the above description of polycarbonate, it won't work too well under the hood, due to significant temperature changes. Otherwise it sounds like a great choice. Maybe the changes can be contained and controlled via oval drilled attachment holes, and flexible gaskets. (weird, it gets smaller when it is heated)
But I wonder if an hour (or four) worth of track time would cause it to soften and sag. Anyone know how hot the engine compartment gets?
How important is the inside shape? Does it have to have a specific shape, or will a larger or smaller interior volume work just as well? The polycarbonate could probably be formed into simple box-like shapes much more easily than the complex curves and forms it has now.
How about an insert or window of pyrex glass? While a full cover of clear material is really cool, maybe all you need is a large window?
Can you post a picture of the part you are talking about (so I'm not going off in the weeds talking about something completely different... )
I've had quite a bit of plastics experience and don't think there's anything clear that will hold up (engineers always like to get prototype cases made whenever possible so they can see what's really going on inside and because it looks neat). Lexan is probably the best, but I think it's marginal for temperature and it has rather poor resistance to many solvents.
I'm pretty sure the OEM cover is glass filled for dimensional stability and rigidity. Straight Lexan will expand and contract too much with temperature and warp so it won't seal.
Originally posted by stever ...engineers always like to get prototype cases made whenever possible so they can see what's really going on inside and because it looks neat...
Yeah, I had an Apple PowerBook 170 prototype in clear plastics. Then I sent it to Africa.
I always wanted to take the cover off. Finally did it. All the nuts are 10mm; be VERY CAREFUL though - the ones at the back are hard to get your fingers to - so the risk of dropping one into never-never land is very great. I loosened the tough ones with a socket on an extension, then loosened it the rest of the way and removed it very carefully with a grabber.
/G
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'01 996 TT - Greg's Porsche Turbo Page
'00 A6 4.2 - doesn't deserve a web page
Greg, thanks for the photos. I saw the drawings of the intake and was very surprised to see the tubes. Does anyone know why they would do this? They almost look like tuned pipes!? Does it have to do with the fluid dynamics of the air? Mixing? I'm confused!
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