{"id":13,"date":"2008-08-17T13:42:33","date_gmt":"2008-08-17T18:42:33","guid":{"rendered":"http:\/\/performancetrends.com\/blog\/?p=13"},"modified":"2011-07-08T11:57:20","modified_gmt":"2011-07-08T16:57:20","slug":"something-for-nothing-power-gains-from-reducing-engine-friction","status":"publish","type":"post","link":"https:\/\/performancetrends.com\/blog\/?p=13","title":{"rendered":"Something for Nothing (power gains from reducing engine friction)"},"content":{"rendered":"

Most engine builders only think of producing more power by making modifications which allow the engine to “breath better”.\u00a0 These include bigger carbs, bigger cams, bigger ports, bigger and more\u00a0 cylinders, force feeding via turbos or superchargers.\u00a0 These all involve improving the Volumetric Efficiency of the engine.<\/p>\n

The next step to better performance would be more exotic, like\u00a0higher compression, different fuels, nitrous oxide<\/a> injection, better\u00a0combustion chambers, dual spark plugs, which allow the engine to make better use of the air and fuel\u00a0that is already getting in the engine.\u00a0 These mods deal with improving the Thermal Efficiency* of the engine.<\/p>\n

After that, most builders and tuners start to run out of ideas.\u00a0 But there is one more efficiency which can produce large performance improvements and that is improving the Mechanical Efficiency of the engine.\u00a0 Volumetric and Thermal Efficiency produce high pressure on top of the piston and push the piston through it’s stroke.\u00a0 This pressure may produce, say, 500 HP at 6000 RPM.\u00a0 In a perfect world you would get 500 HP at the flywheel.\u00a0 However, the friction of the engine’s internal\u00a0moving and rubbing parts can reduce this potential HP down to 400 HP at the flywheel. Then you have some accessories like the oil pump and water pump, alternator and cooling fan, and you’re down to 350 HP.<\/p>\n

These losses deal with the Mechanical Efficiency of the engine, which means for the gross power that is produced on top of the pistons, how much actually gets to the flywheel.\u00a0 These friction losses<\/a> are often forgotten until you’ve maxed out the Volumetric and Thermal Efficiency.\u00a0 However, there are substantial gains to be made.<\/p>\n

The graph below was done with our Engine Analyzer Pro.\u00a0 It shows that at 6000 RPM an engine that produces about 400 HP after it gets past about 80 HP of internal friction.\u00a0 It also shows a comparison run where we asked the Pro to simulate a smaller piston skirt and lower tension piston rings.\u00a0 It shows about a 14 HP drop in friction which results in a 14 HP gain.\u00a0 And that is produced with NO additional fuel or air being burned.\u00a0 That’s about as close to “a free lunch” or “something for nothing” as you can get.<\/p>\n

\"Engine<\/a>
Engine Analyzer Pro HP and Friction HP<\/figcaption><\/figure>\n
Click image above for a larger, clearer\u00a0view.<\/div>\n

The screen below shows the Engine Analyzer Pro’s Short Block screen, where you can make many mods to check the effect on engine friction.\u00a0 If you click on the “Clc” button for\u00a0Bearing Friction Coef, you are presented with a screen that lets you change number of journals, and the journal diameters and widths for the mains, rods and cam.\u00a0 These inputs let you get quite detailed for different mods.<\/p>\n

\n
\"Engine<\/a>
Engine Analyzer Pro Short Block Screen<\/figcaption><\/figure>\n<\/div>\n
Click image above for a larger, clearer\u00a0view.<\/div>\n
I have to temper the “something for nothing” comment because there is a price to be paid.<\/div>\n
    \n
  1. \n
    Friction mods are typically precise, internal modifications to the engine.\u00a0 These are not cheap and are not “bolt ons”.<\/div>\n<\/li>\n
  2. \n
    Typically friction mods reduce the strength of some engine component.\u00a0 If that component was 10 times stronger than needed, no problem.\u00a0 However, if it was only 50% stronger than needed, you may have a problem.\u00a0 The idea is to make all rubbing surfaces as small and\/or friction free as needed for your type of racing.\u00a0 Remember the adage “To finish first, you must first finish.”<\/div>\n<\/li>\n<\/ol>\n

    The graph also shows that the higher the RPM, the more the HP losses.\u00a0 Therefore if you are building a lower RPM street motor, trying to reduce friction would not be the first thing to try.\u00a0 But, if you are building a race motor, where rules severely limit your creativity, reducing friction is a “gold mine” of oportunities.<\/p>\n

     <\/p>\n

    * Technically the “different fuels, nitrous oxide injection” mods deal with the chemical energy contained in the fuel, and finding oxygen to burn the fuel from some source other than air.\u00a0 These mods could be grouped into the Volumetric Efficiency catagory because they deal with getting more<\/em><\/strong> fuel energy\u00a0and oxygen into the engine, not combusting<\/em><\/strong> that energy more efficiently.<\/p>\n

      <\/ol>\n","protected":false},"excerpt":{"rendered":"

      Most engine builders only think of producing more power by making modifications which allow the engine to “breath better”.\u00a0<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[26,24,25],"_links":{"self":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/13"}],"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=13"}],"version-history":[{"count":13,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/13\/revisions"}],"predecessor-version":[{"id":18,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/13\/revisions\/18"}],"wp:attachment":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=13"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=13"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=13"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}