STUDI EKSPERIMENTAL PENGARUH RESTRICTOR VENTURI DAN ORIFICE PADA AIR INTAKE TERHADAP DAYA, TORSI, DAN AIR FUEL RATIO MESIN HONDA CBR 600 CC MOBIL FORMULA BIMASAKTI UGM

Student formula competition is international formula car competition in student class organized by Japan Society of Automotive Engineers. In this competition, students should build a formula car using 4 stroke gasoline engine with 610 cc maximum capacity. The car needs to be studied to get maximum result for the dynamic events. One of the way to get it is by modifying the air intake system so that the power and torque are appropriate competition requirement. This research is done by changing the air intake from 4 throttle to 1 throttle with restrictor system of 20 mm maximum diameter placed after throttle which is appropriated by SAE International rules. In this research, power, torque, and air fuel ratio that is produced from venturi and orifice will be compared. Both venturi and orifice have same dimensions for the inlet diameter, outlet diameter, and total length.Data retrieving is done by variying gear 1, 2, and 3 which use wheel dynamometer for measuring output power and torque in rear wheels. In this research, venturi in gear 1 generates power and torque 33,7 whp and 17,6 Nm, gear 2 generates 49,8 whp and 27,1 Nm, and gear 3 generates 51,9 whp and 29,7 Nm. While orifice in gear 1 generates power and torque 27 whp and 18,3 Nm, gear 2 generates 35,6 whp and 26 Nm, and gear 3 generates 37,2 whp and 25,7 Nm. For both venturi and orifice have highest value in venturi gear 3. Power and torque will increase by increasing the speed wheel. However, they will decrease if the power and torque reach the maximum values. The venturi is more efficient than orifice because it has bigger air fuel ratio (lean) and produce bigger power and torque