Outrun Carbon

Computer rendering of a red GT-style front bumper for a Porsche 924S, with a wide radiator opening, an oil cooler opening, brake duct inlets at the corners and amber turn signals

PRINTING A BUMPER

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by

Shaun Abrahamson
in
Computer rendering of a red GT-style front bumper for a Porsche 924S, with a wide radiator opening, an oil cooler opening, brake duct inlets at the corners and amber turn signals

The 924S needs a new nose. The stock bumper and the lip under it were never meant to feed brakes, a radiator and an oil cooler at race pace. And we shredded the last version in testing.

So we’re printing one. Design is done on screen almost entirely by Claude. What’s super noticeable is how much more proficient Fable is vs previous models when it comes to mechanical design.

For example the sharing current mount points and a few pictures resulted in a complete first rendering that was pretty close. There were some packaging issues like where to run brake cooling ducts – we have important things like a giant loudspeaker instead of a horn. But then there was a bunch of proposed and quick math on sizing and routing airflow to radiator and oil cooler, without any prompting.

We’re a few days from test fit but this is from a a few photos to get reference measurements.

Computer rendering of a red GT-style front bumper for a Porsche 924S, with a wide radiator opening, an oil cooler opening, brake duct inlets at the corners and amber turn signals
The whole bumper, rendered from the design. The amber blocks stand in for the stock turn signals.

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ONE PART INSTEAD OF TWO

The new bumper replaces both the stock bumper cover and the separate spoiler below it. GT-style: flat face, raked chin, everything the car needs cut into it.

  • A forward-facing brake duct inlet at each corner, with a spigot for 2.5-inch hose
  • A bigger radiator mouth
  • An opening for the oil cooler on the passenger side
  • The stock turn signals, kept
  • Easy mount points for the metal wire screens to protect from stones, etc

It bolts to the stock mounting points. The brackets come off the old bumper beam and bolt onto the printed one. Claude did all the math here again.

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FITTING A BUMPER IN A BOX

The bumper is about 1.6 metres wide. The printer bed is 325 × 320 mm. So it prints as ten segments that bolt together, in ASA, which handles heat and sun better than the usual printing plastics.

The same bumper rendering with its ten printed segments shown in alternating orange and grey
The ten segments, in alternating colours.

The corner segments are the tight ones. Each carries a whole turn signal and a whole brake duct, and fits the bed with about 7 mm to spare on each side. Most of the other segments print two at a time.

Ten print plates seen from above, each showing bumper parts laid out on a 325 by 320 mm printer bed
The print plates, seen from above. Each box is the printer bed; the corner segments (plates 5 and 6) only fit turned at an angle.

All in, it’s close to 7 kg of plastic.

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NEXT

We’ll run a test fit and tweak the design then do a single shot lightweight version with the folks from https://swellcyclesurfboards.com/ since they can do this as single part and have lots of tricks to remove weight and keep strength.