Urethane front splitters. Any interest?

[333pg333]

Guys, I've noticed that on Rennlist there is a guy who is going to make up a bunch of these out of Urethane if anyone is interested? I guess it's a personal taste issue, but I quite like the look of some front spoilers however if you have a lowered car, the fibreglass ones have a habit of catching things and breaking off. or just cracking. This may be a solution. I'm going to try one out. Just thought you may like to know about it.

Patrick

 

[333pg333]

Nobody? Nevermind, I'll get one if he does it and let you know. Maybe you guys don't like the front disrupted?

 

[John Sims]

To be honest, as there wasn't a direct link I couldn't be bothered to search. A picture or two would be interesting though.

 

[Diver944]

I'm not particularly knowledgeable on materials but what's urethane? [&:][&:][&:]

Is it bendy, flexible so can't be broken on our plethora of speed humps?

 

[Guest]

ORIGINAL: Diver944

I'm not particularly knowledgeable on materials but what's urethane? [&:][&:][&:]

Is it bendy, flexible so can't be broken on our plethora of speed humps?

Paul,

Its what your front bumper is made of, so yes it is more flexi than f/g

 

[sawood12]

I'd imagine the front bumper are probably made of ABS (Acrylonitride Butadyene Styrene - no doubt spelt incorrectly), Poly Urethane can take two forms - either a self-skinning foam type form like our rubber tailgate spoilers where there is a smooth sealed skin on the outside and it is bubbly inside like an Aero, or a very tough plastic which is much more flexable, like the under-bumper batwing and wheel arch liners. I'd imagine for these splitters it would be the latter. ABS is flexible but not that flexible and will tend to crack and snap when it is bent too far. Poly Uerathane will bend much more than ABS and when it is over-bent wont snap but just plastically deform as it is much more fiberous in it's structure. ABS is used for bumpers because it can be injection moulded and can achieve very accurate and repeatable shapes and you can get a much better surface finish so looks better asthetically. With Poly Urethane it isn't quite so easy to achieve a high quality asthetic finish and they cannot be painted very successfully - for different colours the plastic itself is coloured rather than paint over it - which is not ideal for a production line where there are lots of colour combo's.

I'd be interested in seeing what these turn out like and what the cost is. I much prefer the look of the AIR splitters that are more common in the states over the ESS splitter people tend to have here. I am a bit concerned about a splitter now my car has been lowered. I realise the ESS splitter will probably give me more clearance. However my car budget is earmarked for other mods at the moment.

 

[stevespic]

A Link and some pics would be handy...

Thanks Steve.

 

[333pg333]

Well I can't post links here very easily but go to Rennlist and search the forum
'944 turbo and turbo S' for urethane and you'll find what I'm alluding to.
With Urethane it's true that it can be produced in different guises, but think skateboard wheels. Sort of a stronger yet flexible rubber.
As for splitters I was under the misapprehension that they were only for downforce hence the splitters that stick straight out forwards were of no use. I was wrong though. They are designed to maximise the low and high pressure zones over and under the car.
Check out these links. Very interesting I thought.

www.autospeed.com/A_2159/cms/article.html
www.autospeed.com/cms/A_2160/article.html
www.autospeed.com/cms/article.html?&A=2160

 

[John Sims]

ORIGINAL: sawood12

I'd imagine the front bumper are probably made of ABS ........

Many modern cars are but my understanding is the 944 is PU.

Some of what you say regarding PU is true but the the rage of PU materials is so vast as to almost encompass every material property from extremely soft and floppy to fantastically hard and brittle. It can even have a foam like core and a denser outer skin (as used for steering wheels and dashboards for example) It is all down to the properties the chemists engineer into the base materials.

PU isn't difficult to paint (you have Polyurethane paint any way) but, as with any shiny flexible surface, it is difficult to get paint to stay there. Ideally you should use an etching primer (this will also kill any residual release agent which may have been used in the mould) and an elasticiser in the paint.

The principal difference between ABS and PU is that ABS is thermoplastic and can be vacuum formed or hot injected where as PU is a two part fluid material (Polyol & an isocyanate) which is either injection or puddle moulded cold (although some heating of the mould can be employed to accelerate curing) PU is more expensive.

PU isn't fibrous in its self although fibres could be added to the mix as a filler - chalk is used as a filler in some PU's mainly to reduce the quantity of the expensive polyol. Chalk (or other fillers) reduce the internal bond of the material and can be evident in producing a white residue if the unpainted material is scratched. Unfilled PU will retain its colour within the scratch.