u/Jaded_Street_5756

Anyone else have a Saab where every job somehow creates three more jobs?

I've got some bumper intake ducts that need finishing, some composite part moulds, CAD work for the Carlsson bodykit and reimagined whaletail and many more...

So I picked one small job and just got it done: printed a replacement Lucas MAF housing.

The car was running Trionic 5, so the MAF itself isn't actually being used anymore, but the intake still needs something there. Measured the original, modelled a replacement in Fusion then printed it in PET-CF.

Original was around 1 kg. The printed one is about 150 g.

Nothing particularly exciting, and definitely not the most important thing on the car. But it went from idea → finished part in one day, which honestly felt pretty damn good.

Maybe that's the trick with these projects: occasionally pick the stupidly small thing and just finish it.

Anyone else constantly end up with projects within projects? How do you stop yourself from starting another thing before finishing the last one?

I recently finished reverse engineering the intake duct from a Saab 900 Carlsson front bumper.

The interesting part wasn't really the printing but creating a CAD model that can be reproduced and modified instead of relying on one ageing original.

The workflow looked like this:

• 3D scanned the original duct and bumper (Einstar Rockit)
• Rebuilt the geometry in Fusion 360
• Printed around 7 prototypes using Polymaker HT PLA GF

The nice thing now is that if I want to design brake cooling, oil cooler ducting or make other changes, it's just another iteration of the CAD model and press print.
For an actual part I believe ASA-CF is a good choice of material

I documented the whole project here:
https://ap9engineering.com/saab-900-carlsson-intake-duct/

This ended up being a cool surface modelling project in Fusion 360

The goal wasn't just to make a copy of a rare Saab 900 Carlsson intake duct - I wanted a fully editable CAD model that I can modify and build on in the future.

The workflow was:

• Scan the original duct and bumper with an Einstar Rockit
• Import the scan into Fusion 360
• Rebuild the part from scratch using 3D sketches and lofted surfaces
• Print, test fit, tweak, repeat

I think I went through around 15 prototypes before I was happy with the fit.

One thing I didn't expect was discovering that the original ducts and even the bumper itself aren't perfectly symmetrical, so simply mirroring one side wasn't an option in this case.

This was my first project where I relied heavily on surface modelling, so I'm sure there are cleaner ways to approach such part. I'd be interested to hear how others would have tackled the surfacing.

I wrote up the whole process here if anyone's interested:
https://ap9engineering.com/saab-900-carlsson-intake-duct/

I've been working on reverse engineering the Carlsson intake duct for the past week.

The original goal was to create a proper CAD model so I'm not relying on my only pair of original ducts. I'm also planning to produce a small batch of carbon fibre Carlsson bumpers, so having the duct in CAD makes reproducing it much easier.

I scanned both the ducts and the bumper with an Einstar Rockit, rebuilt everything from scratch in Fusion 360, and went through around 7 prototype prints before I was happy with the fit.

One thing I didn't expect was finding that the bumper openings and the original ducts aren't perfectly symmetrical. The left cavity is about 5mm deeper than the right.

If anyone's interested, I wrote up the whole process (with more photos) here:

https://ap9engineering.com/saab-900-carlsson-intake-duct/

Hi all,

I've owned a Saab 900 since 2008 — it was my first car, and I've been working on and modifying it ever since. That eventually led me to founding AP9 Engineering, where I design and manufacture parts I needed for my own car but that were hard to find elsewhere.

I've now launched an online shop where everyone can browse and purchase these parts: https://ap9engineering.com/

Currently available:

• Rubber suspension components, including new spring seats I manufacture myself
• Composite parts

New parts are in development constantly — progress and behind-the-scenes insight get posted on the blog, and finished products go up in the shop as they're ready.

Note: All prices include VAT. If you're outside the EU, tax is removed automatically at checkout.

If you're interested, have a look, browse around, and feel free to ask any questions.