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REDS 521 Sport .21 Off-Road Competition Buggy Engine Combo w/2143 Tuned Pipe & M Manifold (Broken In)


The REDS 521 Sport .21 Broken In Off-Road Competition Buggy Engine Combo with 2143 tuned pipe and M manifold (REDKM210011), delivers a high-end balance of innovation, and quality, and performance - at a mid-range street price. The 521 Sport features technical changes in the 5 port sleeve, combined with updated materials to offer users high reliability, tuning stability, and fuel mileage. The 521 Sport guarantees excellent performance at a reasonable price.

This combo has been broken in using a specific blend of oil for breaking-in nitro engines using the Oil Bath Lapping Machines. The pre-break-in process saves time, and fuel and increases the performance over the traditional break-in process. Only a quick, post-oil bath, break-in process is keeping you from experiencing quality and performance.


  • ALUMINUM CARBURETOR: 521 Sport engine includes the same aluminum carburetor as 721 engines to guarantee reliability and tuning stability. The insulator bushing has been improved with aerospace-grade ultra high strength polymer. Furthermore, the GEN2 carburetor features a double grub screw joint link to allow positioning and fitting with any servo linkage system.
  • STATE OF THE ART DIE CASTING: The unique high stiffness crankcase design is produced with a high-quality pressure die casting process and special aluminum alloy developed by REDS Racing engineers to guarantee higher stiffness and strength.
  • 5 PORT TECHNOLOGY: The piston and sleeve feature updated materials. Thanks to updated 5 port technology, this engine provides really good fuel mileage and a smooth power band.
  • HANDMADE, TUNED, AND ASSEMBLED: Every single engine is hand inspected and compression checked inside REDS Racing headquarters by Mario Rossi to achieve the highest quality standards.
Category: 1/8 Buggy and Truggy
Displacement: 3.5cc
Bore: 16.2mm
Stroke: 16.9mm
Intake ports: 5
Exhaust ports: 1
Front Bearing: 7x19x6mm rubber seal
Rear Bearing: 14x25.4x6mm Swiss-made steel
Carburetor Venturi: 7.0mm (6.0, 6.5, 7.5, 8.0 optional)
Carburetor: VCX2-A Aluminum Short needle
Weight: 345g
Fuel consumption: > 9:00 min
Engine temperature: 110-130°C
Recommended Glow plug: REDS TS3
Recommended pipe: REDS 2143 + M or XONE Torque
Recommended fuel: 25-30% nitro, 8-10% oil
Break-in fuel: 12% oil