Big Turbo - Scale 1:1+

Big Turbo! Big Stutututu!

Multiple Versions (180° - 360°)🔹 Real Size Model 🔹 M3 Screws & Nuts & Skateboard Bearings

Okay… it doesn’t actually go “stutututu,” but it still looks great. I originally aimed for a car-size turbo, but it ended up closer to a truck-size turbo (24 cm × 18 cm). It can be printed/assembled in 180°, 225°, 270°, 315°, and 360° versions. The base configuration is 180° (my photos show the 225° version). A 45° extension-pack is provided as a separate print profile. No glue required. I printed mine in PLA/PLA+.

 

📌 Bill of materials:

2 × 608ZZ bearings (skateboard bearings)
18 × M3×12 HEX Screws (12 mm thread length, standard hex)
18 × M3 nuts (≈2.3 mm height, standard)

❗❗For each additional 45° extension, you need 4 more screws and  nuts. ❗❗

 

🔧 Required tools:

M3 hex Allen wrench (L-shaped)

 

🔧Assembly

1–3. Join the main shaft with screws, insert the bearings, and set the shaft aside together with one half of the main core.
4–7. Insert M3 nuts into the rings and assemble them to the outer shell (I used the 180° ring and cut it in half for better fit).
–8– Start the two end screws at the far end of the ring pair and run them in lightly. Repeat along the entire half. (Before alignment in step 11, do not fully tighten any screws.)
9–10. Place the turbine and compressor rotors on the shaft and secure them with the printed lock screws. (Compressor = more blades; turbine = fewer blades.)
11. Bring the shaft assembly and the matching face half together; verify free rotation. If it binds, slightly loosen screws and realign until the rotor spins freely.
12–13. Fasten the remaining parts to the second core half; now install all remaining screws.
13–14. Join the two turbine halves with two screws — voilà! A small gap between the two halves is expected (and desired): it preloads the bearings on the rotation axis. Without this gap, axis alignment degrades and the blades may contact the casing.

photo assembly

 

 

Boost MeIt just helps me to buy more plastic, and experiment with new designs! 

 

This model is inspired by various real turbocharger designs found online, with practical 3D-printing compromises. It isn’t a perfect replica — the internal flow passages of the turbine and compressor have constant area along the axis, whereas real units typically converge or diverge. (Revolved geometry is sooo much faster to model than swept transitions between profiles along axis, and this was a “one-weekend” project.) Blade profiles for both compressor and turbine are eyeballed. Due to complex internal geometry (especially internal overhangs), small quantatiy piece printing would be difficult. The 45° segmentation eliminates internal overhangs; as a trade-off, the cut lines will be visible on the assembled model. Even so, this looks cleaner than heavy overhang scarring on the underside. This model for the weight and the ammout of screws is very fragile, all the assebly is hold by thin layers of casing, it could be much better - this is the end result of planing the assembly at last moment - i still managed to drop mine 2 min after full assembly and it survived!! 😵

 

🔧 Troubleshooting:

 

The rotor is colliding with the casing
– Identify the contact area. Slightly loosen the nearby screws and see how much clearance you can gain. If the margin is small, try reseating and tightening in a better position. If that fails, gently heat the assembled sub-section (without the rotor) with a hair dryer and bias it outward slightly. As a last resort, reprint the offending casing piece. The intentional “gap” from the final assembly step also affects axial alignment — omitting it can cause rubbing. The model provides ≈2 mm nominal clearance between rotor and casing, which should be within the capabilities of modern 3D printers.

 

The holes for screws are too tight
– Deburr with a knife/deburring tool. You can “cut” the threads in by driving a screw with the wrench. A 3.5 mm drill also works. The design uses a 3.4 mm pilot for M3; if your prints deviate significantly, calibrate your machine’s dimensions.

 

There is a gap between the two halves of the middle core
– That’s intentional: it sets the shaft’s rotational axis with proper preload. The gap should be small, but removing it can introduce problems. Warped edges can enlarge the gap; use a larger brim and reduce brim-to-model distance to mitigate warping.

 

I hear a “plastic-dragging” noise when spinning
– Inspect the bearings first. If they’re fine, check for thin plastic strings around the overhangs below the compressor rotor — this is the most likely source of subtle friction noise.

 

-Knock, knock

-Who's there?

-Stutututu!