kim0663 wrote:Russki wrote:who knows.... stock filler is actually there for reason- it absorbs minor bumps and prevent plastic go straight to the chassis rail during crash.
would foam do the same? i kinda doubt that - it might just fill the space...
perhaps (in a trouble of fitting stock one ) i will just custom cut new one or modify old one in some sort of way...
You don't need one and it's a waste of time making one (foam, poly whatever) up for it.
Stock bumper skin is like really soft and doesn't retain it's shape properly and you can't even push on it. FRP however, will retain it's shape and if you bump into something, it's not as forgiving as the stock bumper it's just going to crack; whether theres foam behind it or not
According to the inside of the stock bumper, it *is* FRP (but apparently some different kind of FRP from epoxy or polyester resin and glass cloth).
I think the main point of the polystyrene foam is that it might save a pedestrian's legs. Without the foam, the FRP bumper will rapidly deform and the legs will come into more-or-less direct contact with the bumper iron. Add a polystyrene foam block, and it will spread the force over a wider area. This might also save your car from structural damage in a relatively low-energy collision.
The polystyrene may also act as a stiffener, stopping your bumper from sagging when it gets warm, a potential problem for both stock-bumper-type FRP and fibreglass.
I'd guess that polyurethane foam from a can would do more or or less the same as polystyrene. But I think it would be somewhat heavier. It might also absorb water, which could make it a lot heavier. (But perhaps stealthy by absorbing microwaves ??? ).
There must be somewhere where you can buy blocks of polystyrene to carve into the right shape.
im trying to find somewhere in nz to get a boarder kit for a sw20 from..