TECH-TIPS Torque Foot pound to Newton meter: ft·lbs x 1.356 Newton meter to Foot pound: Nm x 0.737 Torque = Horsepower x 5252 RPM Example: Harley-Davidson has rated the Evolution motor at 69 horsepower at 5000 RPM. What is the torque? Torque = 69 x 5252 5000 = 72.5 1 Horsepower = 550 foot/pound per second = 76.04 kg/mtr per second 1 Horsepower = 0.736 Kilowatt 1 Kilowatt = 1.36 Horsepower Horsepower = Torque x RPM 5252 Example: Harley-Davidson has rated the Evolution motor at 82 ft·lbs of torque at 3600 rpm. What is the Horsepower? Horsepower = 82 x 3600 5252 = 56.2 Engine Displacement: Bore x Bore x Stroke x 0.7857 x number of cylinders Example: Stock Big Twin Evolution Engine has 3.5” bore and 4.25” stroke Bore x Bore x Stroke x .7857 x 2 cylinders 3.5” x 3.5” x 4.25” x .7857 x 2 = 81.81 Cubic inches in Cubic Centimeter: Bore 3.5” = (3.5 x 2.54) 8.89 cm Stroke 4.25” = (4.25 x 2.54) 10.798 cm 8.89 x 8.89 x 10.798 x 0.7857 x 2 = 1341.01 cc Compression ratio Displacement + Combustion chamber volume Combustion chamber volume : 1 Example: for stock Evolution Big Twin Engine Measured combustion chamber volume 83.8 cc Displacement (1 cylinder) 670.5 cc 670.5 cc + 83.8 cc 754.3 83.8 : 1 = 83.8 : 1 = 9 : 1 Harley-Davidson and S&S V-Twin bore, stroke and displacement Bore, stroke and displacement is listed as Harley or S&S has indicated them. For the purists: In most instances the formula to calculate displacement for 2 cylinders (V=πr2h * 2) gives something different, but close. A 80CI Evolution Big Twin, for example, has a real displacement of 81.751CI or 1,339.66cc) Displacement 45CI 46CI 54CI 54CI 55CI 61CI 74CI 74CI 69CI 76CI 100CI 750cc 750cc 883cc 900cc 888cc 1,000cc 1,100cc 1,200cc 1,130cc 1,250cc 1,647cc Engine K, WL & G models XG Street XL Sportster XL Sportster KH models XL Sportster XL Sportster XL Sportster 2002-2007 V-Rod 2008-2017 V-Rod S&S X100 Bore 2 3/4” 3.350” 3” 3” 2 3/4” 3 3/16” 3.350” 3 1/2” 3 15/16” 4.134” 4” Stroke 3 13/16” 2.600” 3 13/16” 3 13/16” 4 9/16” 3 13/16” 3 13/16” 3 13/16” 2.835” 2.835” 4” Big Twin Displacement 61CI 74CI 74CI 74CI 80CI 80CI 80CI 93CI 96CI 103CI 107CI 111CI 113CI 124CI 1,000cc 1,200cc 1,200cc 1,200cc 1,300cc 1,340cc 1,340cc 1,530cc 1,575cc 1,691cc 1,754cc 1,807cc 1,852cc 2,035cc Engine 1936-1947 Knucklehead 1930-1948 Flathead 1948-1965 Panhead 1966-1977 Shovelhead 1940-1948 Flathead 1978-1984 Shovelhead 1984-2000 Evolution S&S KN93, P93, SH93 S&S V96 S&S P103, SH103 S&S V107 S&S V111 S&S V113 S&S V124 Bore 3 5/16” 3 5/16” 3 7/16” 3 7/16” 3 27/64” 3 1/2” 3 1/2” 3 5/8” 3 5/8” 3 5/8” 4” 4 1/8” 4” 4 1/8” Stroke 3 1/2” 4 9/32” 3 31/32” 3 11/32” 4 9/32” 4 1/4” 4 1/4” 4 1/2” 4 5/8” 5” 4 1/4” 4 1/8” 4 5/8” 4 5/8” Twin Cam Displacement 88CI 95CI 96CI 103CI 110CI 111CI 120CI 124CI 143CI 1,450cc 1.557cc 1,573cc 1,690cc 1,803cc 1,807cc 1,967cc 2,026cc 2,231cc Engine 1999-2006 2000-2004 2007-2017 2005-2017 2003-2017 S&S T111 2011-2017 120R S&S T124 S&S T143 Bore 3 3/4” 3 7/8” 3 3/4” 3 7/8” 4” 4 1/8” 4 1/16” 4 1/8” 4.425” Stroke 4” 4” 4 3/8” 4 3/8” 4 3/8” 4 1/8” 4 5/8” 4 5/8” 4 5/8” Milwaukee Eight Displacement 107CI 1,753cc 114CI 1,868cc 117CI 1,917cc 124CI 2,035cc 128CI 2,100cc Engine 2017-up 2017-up 2018-up 107CI with S&S BigBore kit 114 or 117 with S&S BigBore kit Bore 3 15/16” 4 1/64” 4 5/64” 4 1/4” 4 1/4” Stroke 4 3/8” 4 1/2” 4 1/2” 4 3/8” 4 1/2” www.zodiac.nl 27-001
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