O.S.SPEED B21 ADAM DRAKE 4 - 3.5cc Off-Road Buggy Racing Engine
O.S. Engines would like to introduce new O.S.SPEED B21 ADAM DRAKE 4. The latest collaboration engine with world famous O.S. Team driver Adam Drake.The cylinder liner, crankshaft & cooling head has been redesigned to Adam Drake’s spec for better balance, more torque and more power for better driving performance.
Main changes (compared to AD3):
- Cylinder liner: Revised port-design for more torque.
- Crankshaft: Inner diameter has changed for better low to mid end power.
- Combustion chamber: Redesigned for more torque
- Outer head: Extra fin for better cooling, reduced weight, lower center gravity for better balance and new laser design with double anodized colors.
First deliveries are expected in December 2025.
Specs:
- Displacement: 3.49cc
- Bore: 16.4mm
- Stroke: 16.55mm
- Output: 2.65ps / 2.61hp @ 34.000RPM
- Practical RPM range: 4.000-42.000
- Engine Weight: 352g
Included:
- Glowplug: O.S.SPEED P3
- Reducers: 6II (blue) AL2 & 8mm (blue) AL
- Exhaust seal ring
- Dust cap set: 3/16/18mm
Advice and testing was done by Roar Champion Adam Drake.
Newly designed cylinder liner uses 3 port design. Changing the exhaust dimension for more torque.
Changed crankshaft’s inner diameter for better response in low to middle range.
New outer head has double anodized black and blue with new laser design and at same time lighter and better balance compared to the previous model.
The combustion chamber has been redesigned combustion efficiency has been improved, resulting in more torque.
Comes with φ6II and φ8 blue anodized restrictor venturis.
