The O.S. Speed B21 AD3 Adam Drake 3 Competition .21 Nitro Engine is the latest evolution of this potent racing engine. Designed in collaboration with the legendary Adam Drake this AD3 edition features several updates and improvements over the already competitive B21 engine platform. The AD3 uses an updated crankcase inner design for linear power making the transition from low to middle to high speeds almost seamless. Adding to this is an updated backplate with a steel lining reducing resistance and aiding in not only extra power but better fuel mileage. Helping to keep weight in check a freshly designed cooling head features a 3mm lower height and is 14g lighter overall lowering the engine's center of gravity and shedding weight in a critical area.
Featuring a semi-long stroke configuration, this engine boasts a DLC crankshaft with larger double tungsten counterweights and a unique cylinder design that’s exclusive to the Drake edition engines. These changes will provide smoother low end power and more overall torque than the previous model. The AD3 is an excellent choice for both buggy and truck racing as it provides a linear power band, exceptional fuel mileage and tons of overall power.
Recommended Pipe and Header for the AD3 Engine:
- Buggy: 2100SC pipe and 75mm manifold
Features:
- Adam Drake’s unique engine specs not used on any other O.S. Speed engine
- Great for buggy and truck racing
- Updated cooling head; 3mm lower height for low gravity and 14g lighter. Black/blue double anodized head.
- Back plate with steel lining like B2104 for friction resistance
- Updated crankcase inner design for linear power transition from low–middle–high speed
- Redesigned cylinder liner with optimized porting
- DLC crankshaft with larger double tungsten counterweight
- Semi-long stroke configuration
- Blue anodized 6.5 and 7.0 mm carburetor reducers
- Ceramic rear bearing
- 21J carburetor
- O.S.SPEED P3 gold plug, great for medium and low speed torque performance, is also included
Specifications:
Bore: 16.4mm / 0.646 in.
Cylinders: Single
Displacement: 3.49cc / 0.213 cu.in.
Engine (Only) Weight: 350g / 12.35oz
Power Type: Glow
Horsepower: 2.61 HP / 34,000 rpm
RPM Range: 4,000 - 42,000
Stroke: 16.55 mm / 0.652 in. output
Includes:
- (1) AD3 Engine
- (1) Engine to Header Gasket
- (1) P3 Gold plug
- (1) 21J carburetor
- Blue anodized 6.5 and 7.0 mm carburetor reducers
This product was added to our catalog on October 20, 2022
