Guest Z-rific Posted October 19, 2003 Share Posted October 19, 2003 Okay, while drinking at the local pub with some old friends, a friend of mine (car guy) and I were talking cars and somehow I mentioned the fact that Horsepower and Torque always cross on a Dyno sheet at the same place, 5250 RPM's. I had remembered reading this once but forgot why and how. To make things interesting, we put a little side bet as he absolutely laughed at me. I went home that night and researched the internet for info, and found that I was indeed correct. Dynos actually measure Torque and derice Horsepower from a formula where 5250 is a constant number. I printed up some articles and he basically caved in. Then, a friend of his (car guy 2), one night agreed with car guy 1 and said I was nuts. Apparently, these experienced auto guys could give many "real life" examples of why I was wrong. I figure I can get tons of reassurement here. And maybe give them this link, so they can see the light and pay up. My official stand is... Horsepower and Torque always cross on a Dyno chart at 5250 rpm's and thus are always equal at 5250. Quote Link to comment Share on other sites More sharing options...
yo2001 Posted October 19, 2003 Share Posted October 19, 2003 Yes, unless you got 502 ci caddy with 5000rpm redline. Quote Link to comment Share on other sites More sharing options...
Guest Nic-Rebel450CA Posted October 19, 2003 Share Posted October 19, 2003 Links are gooood http://auto.howstuffworks.com/question622.htm BTW, the exact number is 5252. Courtesy of my other favorite site In short, HP = (Torque x RPM)/5252. Therefore, where RPM = 5252 the equation would be Torque x 5252 / 5252 or Torque x 1 which equals the Torque. Which makes you right (if you say 5252 and not 5250). Quote Link to comment Share on other sites More sharing options...
Pop N Wood Posted October 20, 2003 Share Posted October 20, 2003 My official stand is... Horsepower and Torque always cross on a Dyno chart at 5250 rpm's and thus are always equal at 5250. Only if you measure power in units of horsepower and torque in units of foot-pounds. Pick up a foreign car mag and you will see torque rated in Newton-meters and power in terms of kilowatts. On these graphs the power and torque curves will not cross at "5252". So by bar bet rules (where you try to sucker someone into losing on the most BS technicality possible), your buddies win. Although probably not because they know what they are talking about. Power and torque are mathematically related, just like speed and distance. That is where 5252 comes from. The link posted above tells you exactly how to compute it. Quote Link to comment Share on other sites More sharing options...
Guest Z-rific Posted October 20, 2003 Share Posted October 20, 2003 Hey Dog, We agreed that torque would be measured in foot/lbs. So I covered myself there. And, if an engine never reaches 5000 rpms, well then HP and torque are still the same at 5000.....ZERO. Quote Link to comment Share on other sites More sharing options...
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