{"id":8,"date":"2008-07-18T17:28:09","date_gmt":"2008-07-18T22:28:09","guid":{"rendered":"http:\/\/performancetrends.com\/blog\/?p=8"},"modified":"2008-07-20T13:35:35","modified_gmt":"2008-07-20T18:35:35","slug":"engine-analyzer-pros-valve-train-dynamics-vs-spintron","status":"publish","type":"post","link":"https:\/\/performancetrends.com\/blog\/?p=8","title":{"rendered":"Engine Analyzer Pro’s Valve Train Dynamics vs SpinTron"},"content":{"rendered":"

The higher you can rev the race\u00a0engine (providing it can breath well) the higher the power output.\u00a0\u00a0 The valve train has been one of the major roadblocks\u00a0to trying to achive these\u00a0higher RPMs.\u00a0 At high RPM, the mass in the valve train puts trememdous strain on the pushrods and other components as you try to get the seated valve to open, then keep it from lofting or tossing off the nose of the cam, then keep it from slamming closed and bouncing off the seat.\u00a0 All this has to happen in about 1\/200 second at about 10,000 RPM.\u00a0\u00a0\u00a0 For you camara buffs, think of a shutter speed of 1\/200.\u00a0\u00a0For you physicysits and drag racers, the valve can be going through\u00a02000\u00a0Gs or more. \u00a0 That’s fast.<\/em><\/strong><\/p>\n

Lots of technological advances have been made over the years, lighter and stiffer components, more durable valve springs materials\u00a0and designs, 4 valve engines (2 smaller valves instead of 1 large valve), etc.\u00a0 Lots of tools have been used to understand and develop these valve train advancements, including computer tools.\u00a0 One such tool is valve train computer simulation.\u00a0 Another is a valve train “dyno” like the Spintron.<\/p>\n

Our Engine Analyzer Pro includes a valve train simulation.\u00a0 You can choose to turn it On or Off.\u00a0 If you turn it On, you will have to be careful to enter accurate spring rates, valve train weights and effective rocker arm stiffness.\u00a0 However, with it turned on, you can learn a tremendous amount about how valve trains work at high speed.
\n\"Engine<\/a><\/p>\n

In late 1980s, when we started to develop the Engine Analyzer Pro, we knew that valve train dynamics was critical to good engine power production.\u00a0 For example, assuming a perfect valve train the valve should be open, say, .030″ on the opening ramp.\u00a0\"Valve<\/a> But due to\u00a0inertia and valve train bending, it is likely still on the seat at 7000 RPM!<\/em><\/strong>\u00a0 Therefore, we needed a good valve train dynamics simulation.\u00a0 We worked with Tim Gillespie of Comp Cams who shared some pushrod force data.\u00a0 With just a little bit of tweaking of the damping (friction) factors, the Engine Analyzer Pro’s predicted forces were almost “spot on” with what Tim had measured.\u00a0 \"Simulated<\/a><\/p>\n

It all makes sense that you want light components, strong valve springs, and a cam profile which is agressive enough to open the valve enough for good flow, but not overly agressive.\u00a0 However, the flexibility in the valve train is another, often overlooked\u00a0critical aspect to valve trains.\u00a0 Think of a spring board diver.\u00a0 He gets additional height by jumping in synch with the board’s natural frequency.\u00a0 In his case, he wants additional height, or lofting off the board.\u00a0 In the case of the valve train you do not want lofting<\/em><\/strong>.\u00a0 Investigating how the flexibility of the valve train interacts with the valve train’s natural frequency is impossible to calculate without a sophisticated valve train simulation.<\/p>\n

Spintron has gotten some good press lately, and deservedly so.\u00a0 Several race teams use them for testing and developing valve trains.\u00a0 It is a good tool, letting you spin the cam and valve train at high RPM.\u00a0 It requires a VERY large electric motor (25-75 HP, requiring 40-155 amps at 440 VAC).\u00a0 It is also quite expensive, $50K to $100K.\u00a0 Click here for their website\u00a0 www.spintron<\/strong>.com<\/a>\u00a0 <\/font><\/span><\/p>\n

However, there are things even the $100,000 Spintron does not simulate.\u00a0 A major one is the high cylinder pressure working to keep the exhaust valve closed during valve opening.\u00a0 Take a 1.9″ diameter valve head working against, say, 700 psi when it first starts to open.\u00a0 That’s almost 2000 lbs of extra force required to open the exhaust valve.\u00a0 And on blown engines, that cylinder pressure at exhaust valve opening will be much<\/em><\/strong> higher.\u00a0 The extra force to overcome cylinder pressure changes the exhaust valve train dynamics and forces significantly.<\/span><\/p>\n

Bottom line is that both the Spintron and Engine Analyzer Pro’s valve train simulation are useful tools to understand and develop high RPM valve trains.\u00a0 However, the Engine Analzer Pro is available at 1\/100 the price ($469 vs $50,000), requires no special 440 VAC wiring or engine\/engine mods\/prototype parts, and actually does some things better.<\/span><\/p>\n

Some of the pics in this blog are taken from our Engine Analyzer Pro’s user’s manual, Example 4.2 starting on page 167.\u00a0 This manual is a wealth of information, not only on\u00a0how our Engine Analzyer Pro works, but\u00a0on basic race engine operation.\u00a0 Here’s a link to it if you want to read more\u00a0 http:\/\/www.performancetrends.com\/PDFs\/EAPMan4.pdf<\/a><\/span><\/p>\n","protected":false},"excerpt":{"rendered":"

The higher you can rev the race\u00a0engine (providing it can breath well) the higher the power output.\u00a0\u00a0 The valve train has been one of the major roadblocks<\/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":[12,11,15,13,10,14],"_links":{"self":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/8"}],"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=8"}],"version-history":[{"count":0,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=\/wp\/v2\/posts\/8\/revisions"}],"wp:attachment":[{"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=8"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=8"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/performancetrends.com\/blog\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=8"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}