3D‑Printed Heat‑Resistant Intake Manifolds Give Motorsport Bikes a Competitive Edge

Andrea Pirazzini, founder of Help3D, has leveraged Formlabs 3D printers to craft a custom intake manifold for his pit bike, which competes in the 12 Pollici Italian Cup.

In the pursuit of a perfectly linear power curve, Pirazzini employed fluid‑dynamic simulations to refine manifold geometry, eliminating the need for reduction flanges that can create localized pressure drops.

By adopting 3D printing, he could iterate multiple designs at minimal cost, evaluate them the following day, and secure a performance advantage on the track. Teammate Elia Marescutti won the 2021 championship riding a bike equipped with a 3D‑printed manifold.

The winning 2021 S1 Over champion’s motorcycle featured a custom manifold printed on the Form 3.

Reverse Engineering the Manifold to Optimize Performance

Since 2012, Pirazzini has used 3D printing for small functional parts on his motorcycles. He hesitated to tackle larger, heat‑resistant components until Rigid 10K Resin became available.

After a thorough review of its specifications, he decided to challenge the traditional aluminum machining of intake manifolds. Earlier attempts with FDM failed due to air leakage that disrupted carburetor operation and engine output.

He began by 3D scanning the pit bike’s four‑stroke, two‑valve engine and its surrounding frame and carburetor. The data fed into Autodesk Fusion 360, enabling precise sizing and positioning of the manifold to prevent collisions with the frame or exhaust.

Using CAD, Pirazzini aligned the head inlet diameter with the carburetor, eliminating steps that could cause pressure drops or turbulence. He also designed intake trumpets and ducts.

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Different versions of the intake manifold printed on the Form 3 are showcased below.

When the championship rules required power output to be capped, Pirazzini modeled a manifold that limited horsepower without sacrificing linearity. A test bench allowed him to identify the optimal design for each engine configuration.

The result was an extended delivery curve at higher RPMs, achieving roughly 1 HP (≈10 %) more power than a conventional machined manifold while staying within championship regulations.

Using Rigid 10K Resin to Print Heat‑Resistant Objects

The final manifold was produced on the Form 3 with Rigid 10K Resin at a 100‑micron layer height, yielding a smooth surface free of visible layer lines. Pirazzini finished the part with water‑based sandpaper, a common practice for SLA prints that achieve inherent watertightness.

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The print time ranged from two hours to two hours and forty‑five minutes, depending on thickness and size. Each part cost between €10 and €12. Pirazzini was able to print up to seven different manifold variants overnight, testing them the next day.

Andrea Pirazzini, founder of Help3D

“In the world of 3D printing, PreForm is the simplest and overall best‑performing program I have ever used.”

Two versions of intake manifolds are ready to be sent to print using PreForm.

In PreForm, users can manually orient parts or let the software auto‑orient them. Pirazzini found auto‑orientation valuable because it minimizes support structures, which can be added or removed as needed. The software alerts the user if critical supports are missing.

Andrea Pirazzini, founder of Help3D

“One very nice thing about the Form 3 is that the size of the support in contact with the print is tiny, leaving very little residue to remove.”

The Results

Pirazzini’s Form 3‑printed manifold endures extreme temperatures and remains installed on his pit bike. Thermal imaging revealed that the Rigid 10K resin manifold with cooling fins operated 40–50 °C cooler than a standard aluminum manifold.

After a 20–25 minute race at an ambient temperature of about 33 °C, the printed manifold could be touched without discomfort, demonstrating its superior heat management.

Upcoming Projects

The success of the intake manifold is just the beginning. Pirazzini plans to use Rigid 10K resin for reed‑valve packs on two‑stroke engines, tappet covers, reduction flanges for cylinder head couplings, and any other air‑tight component.