Precision Engineered.
Parts for the Porsche 928.
Hard-to-find replacement parts, specialist tools, and modern upgrades developed specifically for the Porsche 928.
From recreating NLA factory components to designing entirely new solutions, Sirius Fabrication combines CAD, additive manufacturing, modern electronics, and hands-on development to keep these remarkable cars on the road and improve the ownership experience.
Built Because They Don't Exist
Owning a Porsche 928 often means discovering that the part you need hasn't been available for decades, the original tool is almost impossible to find, or the solution simply never existed in the first place.
That's where Sirius Fabrication starts.
Parts are developed from original components, factory documentation, careful measurement, prototyping, and real-world fitment wherever possible. Materials and manufacturing methods are selected for the job, whether that means engineering-grade polymers, reinforced composites, metal additive manufacturing, or electronics.
The goal is simple: create thoughtful solutions that belong on the car.
Featured Products
Restore your classic’s instrument cluster with high-precision, heat-resistant replacement gears.
Is your odometer stuck, clicking, or "ghosting" miles? In classic Porsche and VDO-equipped vehicles, the original factory drive gear is made of a soft urethane that chemically breaks down over 20+ years, eventually crumbling into "oatmeal."
Our replacement gears are engineered to exact VDO specifications and 3D-printed in ASA (Acrylonitrile Styrene Acrylate). Unlike original equipment or cheap PLA/PETG replacements, ASA is automotive-grade, UV-resistant, and capable of withstanding the extreme high-heat environment of a vehicle dashboard (up to 100°C/212°F) without warping or softening.
How to Choose Your Gear
VDO used different tooth counts to calibrate odometers for Miles (MPH) vs. Kilometers (KM). To ensure your odometer records distance accurately, you must match the tooth count of your original gear.
Pro-Tip: If your original gear has crumbled, count the teeth on the Partner Gear (the large gear it meshes with) to determine the correct replacement.
GEAR SELECTION GUIDE
20x21 (Miles): Standard for 928 models with MILES odometer. Meshes with a 49-tooth partner gear. Small gear diameter: 12.05mm.
20x29 (Kilometres): Standard for 928 models with KM odometer. Meshes with a 41-tooth partner gear. Small gear diameter: 12.05mm.
20x22 (Miles): Fits specific 944/911 variants. Meshes with a 48-tooth partner gear. Small gear diameter: 9.40mm.
20x23 (Kilometres): Meshes with a 47-tooth partner gear. Small gear diameter: 9.65mm.
20x30 (Kilometres): Late-model 911/944 units. Meshes with a 40-tooth partner gear. Small gear diameter: 12.55mm.
20x32 (Kilometres): Meshes with a 38-tooth partner gear. Small gear diameter: 13.40mm.
European Classics
Porsche: 911 (1976-1989), 912E, 914, 924, 928, 930, 944, 964, and 968.
BMW: 3-Series (E30), 5-Series (E28, E34), 6-Series (E24), 7-Series (E23), Z1, and Z3.
Mercedes-Benz: S-Class (W116, W126, W140), E-Class (W123, W124), SL-Class (R107, R129), and G-Wagen (W460, W461, W463).
Audi: 80, 90, 100, 200, 5000, Coupe, and V8 models.
Volvo: 240, 440, 480, 740, 760, 850, and 940.
Exotics: Alfa Romeo (Giulietta, 156), Lamborghini LM002, Maserati (Quattroporte, GranTurismo), Ferrari, and Alpine A310.
Luxury: Bentley and Rolls-Royce (various models from 1966+ using VDO/Jaeger units).
Japanese & American Models
Nissan/Datsun: 260Z, 280Z, 300ZX (Z31), S13 (SX/Silvia), and Micra.
Honda: Civic (early generations).
Mitsubishi: Eclipse (1st Gen).
Specialty: Vixen Motorhomes, Holiday Rambler, and various John Deere/Ford tractors using VDO hour meters.
Product Features:
Engineered for Precision: Matches the standard 17.6mm large-gear diameter used across Porsche 911, 924, 928, 944, and 968 models.
Superior Material: Printed in high-performance ASA for maximum durability and heat resistance.
Optimized Geometry: Our "solid-hub" design eliminates the structural weakness of the original "recessed" moulded parts, preventing gear-face shearing.
Friction Fit: Designed for both a 2mm bore AND 3mm bore for a secure press-fit on the odometer drive shaft.
Please be sure you have the correct spec and measurements before ordering: bore diameter (2mm or 3mm), gear tooth counts e.g. 20×29, and the gear diameters.
Remember the “rule of 70” - if your odometer gear has truly crumbled, count the teeth on its partner gear. The sum of the teeth must be 70, so if that one has 41 teeth, you need a 20×29
Installation Notes:
Clean Thoroughly: Remove every trace of the old, crumbled gear from the odometer housing. Small debris can jam the new gear and cause mechanical failure.
Clean the shaft of any gear residue. I had to scrape mine to get rid of the hard coating left by the gear material and old grease. Add a small amount of lithium grease to the shaft (not the gears).
No Lubrication Needed on the Gears: ASA is self-lubricating against the nylon partner gears; avoid using heavy greases that can attract dust.
Check the Partner Gear: Inspect the white partner gear for hairline cracks in the center bore, as this is a common secondary failure point.
Restore the critical cooling airflow to your 928's engine mounts.
Introduced in 1987 alongside the S4’s aerodynamic belly pan, these specialized air ducts are vital for managing engine bay temperatures. By directing high-velocity air from the underbody directly onto the engine mounts, they prevent premature heat-soak of the engine mounts - a common issue in the hot, cramped engine bay of the 928.
For years, these ducts have been "unobtainium," leaving owners with overheated engine mounts. Sirius Fabrications has solved this by painstakingly reverse-engineering the original factory geometry to produce a perfect-fit replacement that exceeds OEM standards. Many have tried to recreate these with varying levels of success, but nothing like this has been available until now.
Available in three tough materials using two 3D printing technologies: Fused Deposition Modeling (FDM) and Selective Laser Melting (SLM).
Carbon Fiber Reinforced Nylon (FDM): Lightweight, extremely durable, and heat-resistant. Ideal for those seeking a factory-plus look with modern composite strength. The PA6CF material has excellent corrosion resistance (fuel, oil, hydraulic fluid etc) and can withstand up to 200 deg Celcius before deforming.
316L Stainless Steel (SLM):For the ultimate in longevity. These are solid metal components with incredible corrosion resistance. Please allow 10 to 15 business days lead time.
Aluminium (SLM): Provides high strength-to-weight ratio and excellent corrosion resistance. Please allow 10 to 15 business days lead time.
Key Features:
Perfect Fitment: Painstakingly reverse-engineered in CAD using original reference units to ensure 100% compatibility with the factory 1987+ OEM, and aftermarket aluminium belly pans. Countless prototypes (the grey ones in the photo) were printed and tested until the fit was millimetre-perfect.
Engineered for Heat: Materials selected specifically to withstand the harsh environment of the 928 engine bay.
NLA Solution: Replaces Porsche parts that have been out of production for decades.
The "Stealth" Audio Solution
Upgrading your 928's sound shouldn't mean compromising its soul. Most modern speakers from the big aftermarket car audio brands come with flashy, oversized grilles that look completely out of place in an 80s GT cockpit.
The SF Modular System is designed for the enthusiast who wants modern audio without the aftermarket look. Our 3-piece kit allows you to hide those modern drivers behind a period-correct, understated design that looks like it just rolled off the line in Stuttgart. No gaudy logos—just a clean, factory-integrated finish. 3D printed from carbon fibre-reinforced nylon, which will shrug off a hot sunny day without warping.
Fit. Finish. Factory.
Fit: Precision-modelled threads are 100% interchangeable with original Porsche components. Use our rings on your factory bases, or replace the entire assembly for a rock-solid mount.
Finish: A muted, matte texture designed to blend into the original door cards—not scream for attention. Includes pre-fitted, high-airflow wire mesh.
Factory: A complete 3-piece system (Base, Ring, and Mesh) for both the 4" woofer and 1" tweeter.
The Kit Options (Prices in USD):
Single Housing (4" or 1"): Perfect for replacing one broken unit.
Single Door Set (1 Woofer + 1 Tweeter): Refresh one side of the car.
Full Interior Kit (2 Woofers + 2 Tweeters): The complete resto kit.
Technical Specs:
3-Piece Construction: Includes Mounting Base, threaded locking Ring, and integrated mesh.
OEM Compatibility: Directly replaces/interchanges with Porsche PNs 928.645.427.00 and 928.645.428.00.
Modern Excursion: Deep-profile design ensures clearance for modern high-output drivers (tested with Rockford Fosgate Punch series).
Enthusiast Built: Prototyped and manufactured in Canada specifically for the 928 community.
Our
brand vision
Sirius Fabrication grew out of working on my own 1987 Porsche 928 S4 and encountering the same problems familiar to 928 owners everywhere: unobtainable parts, ageing components, scarce specialist tools, and opportunities to improve the car without compromising its character.
What started with replacement components has grown into a range of restoration parts, workshop tools, and new technology developed specifically around the 928 platform.
Some products faithfully recreate what Porsche originally made.
Others solve problems Porsche never had the technology, or the need, to solve at the time.
All of them start with the same question:
Can this be done properly?
