| as for foam: my brother is an aerospace structural engineer, not just a junior hack, but a chief configurator for a shuttle project. and after describing the foam to him, and inspecting it on a pals' racecar Z32 (slowly breaking loose and creating dust near the openings), I believe foam-filling your unibody frame for added stiffness is utter B.S. I think the whole notion of using foam is a misunderstanding of the useage of certain foams with very thin exotic material skins for airplanes to create some amazingly strong and light structures for sure, but it doesn't translate to use on (relatively) thick steel. The reason this foam is used in cars and is says so right on the cans of the expensive stuff I've seen from group buys, is: Noise, Harshness and Vibration. That's it. Folks may be experiencing less harshness and vibration, but the foam, in order to work, (this comes from a structural engineer, folks) must be as strong or STRONGER than the skin it's in (in this case, layers of 18-guage sheet steel), in order for the two components to make a sandwich that is stronger than either of them alone. IT's not going to happen. The foam is NOT anywhere near as strong as 18-guage steel. Steel, folks, in two or three layers. Sorry. Period. If you had a log of that foam out in the open, I promise you you could snap it in half, no problem. you might literally have an easier time making something using foam that is stiffer than the foam alone-- or the skin alone, if you used fiberglass. But you can't promise that'll be stiffer, or stronger than steel--and thus, better for a street car. I think folks who foam their frames are experiencing the placebo effect. The car "feels different" because noise and vibration are dampered. So they think it's stiffer. I'd need to see a unibody frame on a fourier analyzer that has all those little pickup points and a wireframe model before and after foam, to believe it works. IF the foam even sticks to the insides of the rails!! IF it sticks--(which I'm sure not all of it does-- on a non-prepped steel frame) it will eventually be broken loose due to the fact the foam is weaker than the steel, the steel flexes, and you'll have a nice, loose, foam log floating around in your frame rails, creating dust. what a waste of time and money.
Crash Test Dummy(tm)
"taking it on the chin so you don't have to..." |
