Art. 9901 - This is the results of several tests made in 3.5cc on & off/road races to decrease the noise level. The 3 chamber large volume design improves the torque power with a smooth acceleration curve keeping the same RPM range.

Art. 9853 - This is the best choice for off/road competitions. Used by the most popular 1/8 scale buggy champions due to the low-medium range high torque power. In connection with the in-line manifold it gives the best performance and reliability.

Art. 9886 - The powerful exhaust system especially designed for 3.5cc car racing engines. It is Efra homologated and its usage improves the engine performance in every range especially at the maximum RPM for the fastest speed.