{"id":7,"date":"2008-09-05T08:48:46","date_gmt":"2008-09-05T13:48:46","guid":{"rendered":"http:\/\/performancetrends.com\/blog\/?p=7"},"modified":"2008-09-05T08:48:46","modified_gmt":"2008-09-05T13:48:46","slug":"torque-vs-horsepower-which-is-more-important","status":"publish","type":"post","link":"https:\/\/performancetrends.com\/blog\/?p=7","title":{"rendered":"Torque vs Horsepower, which is more important?"},"content":{"rendered":"

You’ve probably heard various racers and engine builders\/tuners talk about torque vs HP.\u00a0\u00a0Some say “torque is what moves the car”, other’s say HP is all that matters.\u00a0 Well, you’ll have to put me in the latter camp, because HP is <\/em><\/strong>the most important.\u00a0 Torque is how much twisting force you are putting on the driveshaft, typically measured in ft lbs.\u00a0 Horsepower is multiplying this twisting force by RPM (how fast you can keep applying this force).<\/p>\n

If we didn’t have gears, than torque would be more important.\u00a0 That’s because\u00a0in any 1 gear, the torque peak is where the car accelerates the quickest, producing the highest Gs.\u00a0 The torque peak can be important for launching the line, but after that HP is all that matters.\u00a0<\/p>\n

I’ll try to illustrate with some numbers.\u00a0 Gears are torque multipliers.\u00a0 You can get most any torque you want, if you are willing to give up RPM.\u00a0 Say you have 400 ft lbs at 3000 RPM (228 HP) and 350 ft lbs at 6000 RPM (400 HP).\u00a0 If you stay in 3rd gear, you could get .4 Gs acceleration at 3000 (lets say 60 MPH)\u00a0and .35 Gs of acceleration at 6000 (120 MPH).\u00a0 However, if you shifted 1st gear and put that 400 HP to work at 60 MPH, you could get, say\u00a0.7 Gs of accel.\u00a0 You may accelerate the quickest in any 1 gear at the torque peak, but you will accelerate quicker in a lower gear at the HP peak.<\/p>\n

Racing is all about quickest acceleration to get to the highest speed.\u00a0 Gears let you keep the acceleration high by keeping the engine in its highest HP range.\u00a0 In our Drag Race Analyzer and Circle Track Analyzer programs, they find the optimum shift RPMs or final drive ratios by keeping the engine in its highest HP range.\u00a0 For example, if your engine has peak HP\u00a0at 6000 RPM, but pulls strong to 7000 RPM, you would probably want to shift at close to 7000 RPM, so when the revs drop back to, say, 5000 RPM, you are still in a high HP range.<\/p>\n

Let’s try some real examples, using our easy Drag Race Analyzer v3.2.\u00a0 We’ll try shifting to keep the engine around the torque peak, then letting the computer keeping the RPMs around the HP peak.\u00a0<\/p>\n

Condition\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0Pk Tq\u00a0\u00a0\u00a0 \u00a0Pk HP\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 ET\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 MPH\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 Shift RPMs<\/p>\n

Keep Engine at Tq Peak\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0270\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0274\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 13.43\u00a0\u00a0\u00a0\u00a0 99.46\u00a0\u00a0\u00a0\u00a0 \u00a0\u00a0\u00a0 4700<\/p>\n

Computer keeps Engine at HP Peak\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0270 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0274\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 12.66\u00a0\u00a0\u00a0\u00a0 106.81\u00a0\u00a0\u00a0\u00a0\u00a0 \u00a06800<\/p>\n

Computer keeps Engine at HP Peak\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0270\u00a0 \u00a0\u00a0\u00a0\u00a0\u00a0\u00a0268\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0\u00a0 12.60\u00a0\u00a0\u00a0 \u00a0107.74\u00a0\u00a0\u00a0\u00a0 \u00a0 6950
\n(broader HP peak)<\/p>\n

\u00a0<\/p>\n

\"Standard<\/a>
Standard Power Curve<\/figcaption><\/figure>\n

\u00a0<\/p>\n

You can see the performance is much better when you keep the engine in the high HP range (12.66 ET)\u00a0as opposed to the high torque range (13.43 ET).\u00a0 The graph below shows how keeping the engine in a higher HP range in lower gears produces higher acceleration rates.\u00a0<\/div>\n
\n
\"Acceleration<\/a>
Acceleration in Gs vs MPH. Blue is keeping engine at HP peak, green is keeping engine at torque peak<\/figcaption><\/figure>\n

\u00a0Click on image to enlarge it.<\/p><\/div>\n

\u00a0<\/p>\n

You will see a third line in the table of results, where I used a power curve with 6 less peak HP, but a broader HP peak. \u00a0It shows better performance (12.60 ET) than the curve with more peak HP. This makes the point that it is the “area under the HP curve” which is actually most important, or the highest average HP over the RPM range you are using.Power Curve with Lower, but Broader HP Peak<\/p>\n

\u00a0<\/p>\n

\"Power<\/a>
Power Curve with Lower, but Broader HP Peak<\/figcaption><\/figure>\n

\u00a0<\/p>\n

To summarize, it is HP through the correct gear ratio which produces best performance.\u00a0 If you are building an engine, you want the highest average<\/em><\/strong>HP through the RPM range you will be using.\u00a0 For a circle track car where you don’t shift, this can be a very broad RPM range.\u00a0 For drag racing with a high stall converter or very narrow ratio transmission, this may be a very narrow RPM range.\u00a0 The Performance Trends vehicle programs like Drag Race Analyzer (std or Pro version), Circle Track Analyzer, or Transmission Gear Calculator will help you optimize your engine and vehicle combo.<\/p>\n","protected":false},"excerpt":{"rendered":"

You’ve probably heard various racers and engine builders\/tuners talk about torque vs HP.\u00a0<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[9,7,8,3],"tags":[84,27,28,29],"_links":{"self":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7"}],"collection":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=7"}],"version-history":[{"count":4,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7\/revisions"}],"predecessor-version":[{"id":34,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/7\/revisions\/34"}],"wp:attachment":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=7"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=7"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=7"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}