EcoModder Forum Math help......

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 04-03-2020, 01:04 PM #1 (permalink) Master EcoModder   Join Date: May 2010 Location: Illinois Posts: 452 Oh Deer - '03 Ford Ranger XL 90 day: 33.16 mpg (US) Thanks: 54 Thanked 79 Times in 63 Posts Math help...... I like math, but can't understand why I can't convert this formula. Maybe it's the 12 hour nights at the nuclear plant or the radiation scrambling my brain. I need to convert this...... MPH = [60 / (transmission gear ratio x axle ratio)] x [engine RPM / tire revolution per mile] into this....... engine RPM = ???????? I don't need it for the Ranger in my signature, but for my project Triumph TR7. I need to decide what I want for a rear end to get a nice RPM highway cruising range. I already know the new tire size and new transmission ratios that go along with the engine swap I have planned. Thanks __________________
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 04-03-2020, 01:39 PM #2 (permalink) Moderator     Join Date: Feb 2012 Location: Champaign, IL Posts: 1,850 Pope Pious the Prius - '13 Toyota Prius Two Team ToyotaSUV 90 day: 51.9 mpg (US) Tycho the Truck - '91 Toyota Pickup DLX 4WD 90 day: 24.12 mpg (US) Thanks: 197 Thanked 1,653 Times in 870 Posts Engine RPM = [MPH x (transmission gear ratio) x (axle ratio) x (tire revolutions per mile)] / 60 __________________
 The Following User Says Thank You to Vman455 For This Useful Post: hat_man (04-03-2020)
 04-03-2020, 02:07 PM #3 (permalink) Master EcoModder   Join Date: May 2010 Location: Illinois Posts: 452 Oh Deer - '03 Ford Ranger XL 90 day: 33.16 mpg (US) Thanks: 54 Thanked 79 Times in 63 Posts Thank you. I haven't figured out what I was doing wrong, but the numbers I was coming up with were so far off I knew I had messed up someplace. __________________
 04-03-2020, 02:13 PM #4 (permalink) Master EcoModder   Join Date: May 2010 Location: Illinois Posts: 452 Oh Deer - '03 Ford Ranger XL 90 day: 33.16 mpg (US) Thanks: 54 Thanked 79 Times in 63 Posts After looking at what I had on paper I have come to the conclusion that it really helps if you write things in the SAME order as you type them. Really messes things up when you have RPM (engine speed) and confuse it with rpm (revolutions per mile). SMH __________________
 04-03-2020, 08:15 PM #5 (permalink) Ecomodding amateur     Join Date: Nov 2015 Location: Indiana Posts: 655 The Van - '95 Chevy Astro Cl V8 Swapped Team Chevy 90 day: 9.5 mpg (US) The new bike - '17 Kawasaki Versys X 300 abs Motorcycle 90 day: 64.68 mpg (US) The Mercury - '95 Mercury Tracer Trio Team Ford 90 day: 37.77 mpg (US) Thanks: 119 Thanked 238 Times in 171 Posts Spicer also has an online calculator. https://spicerparts.com/calculators/...rpm-calculator __________________ Věci získávají svou skutečnou krásu pouze ve vztahu k našemu životu -Jiří Mucha (1915-1991), Publicist 1973 Fiat 124 Special 1975 Honda Civic CVCC 4spd 1981 Kawasaki KZ750E 1981 Kawasaki KZ650 CSR 1983 Kawasaki KZ1100-A3 1986 Nissan 300zx Turbo 5 spd 1995 Chevy Astro RWD (current project) 1995 Mercury Tracer 2004 Chevy Astro AWD 2017 Kawasaki VersysX 300 https://www.youtube.com/channel/UC6s...LulDUQ8HMj5VKA
 04-04-2020, 06:46 PM #6 (permalink) Master EcoModder   Join Date: Dec 2010 Location: Arkansas Posts: 839 Sport Utility Prius - '10 Toyota Prius II 90 day: 59.63 mpg (US) The Smoke Bomb - '96 Ford Ranger 90 day: 25.97 mpg (US) CB 750 - '00 Honda CB750 Nighthawk 90 day: 55.87 mpg (US) Killer 650 - '07 Kawasaki KLR650 90 day: 45.83 mpg (US) Sequoia - '04 Toyota Sequoia Limited 90 day: 18.36 mpg (US) Thanks: 244 Thanked 186 Times in 146 Posts https://www.tremec.com/calculadora.php 1st: 3.72 2nd: 2.20 3rd: 1.50 4th: 1.00 5th: 0.79 Gear: 3.73 Tire: Whatever you have. __________________ "I feel like the bad decisions come into play when you trade too much of your time for money paying for things you can't really afford."