{"id":7680,"date":"2014-08-26T15:16:49","date_gmt":"2014-08-26T22:16:49","guid":{"rendered":"http:\/\/www.racingjunk.com\/news\/?p=7680"},"modified":"2016-11-30T17:09:54","modified_gmt":"2016-12-01T01:09:54","slug":"headers-scavenging-games-part-iv","status":"publish","type":"post","link":"https:\/\/www.racingjunk.com\/news\/headers-scavenging-games-part-iv\/","title":{"rendered":"Headers: Scavenging Games Part IV"},"content":{"rendered":"

Drag Race 101:<\/strong>\u00a0Headers, Part IV<\/p>\n

Recall a few posts back, \u00a0when we mentioned formulas and software that can help to figure out header dimensions?\u00a0 We\u2019ll, we’re bringing you a couple of header formulas below and if you need to check out a neat software program that can do much of ground work for you, try pointing your browser to: http:\/\/www.maxracesoftware.com\/PIPE395.htm<\/a>.<\/p>\n

When it comes to the formulas below, no real absolutes exist.\u00a0 On the other hand, the pipe dimensions that result from the math should help to put your project on the right track.\u00a0 You\u2019ll also discover that the header primary tube diameter and length are interrelated.\u00a0 That means if you \u201clengthen\u201d the tube size, it has an effect upon the tube diameter.<\/p>\n

For our same test, we already knew that the maximum engine displacement was 402 cubic inches and the motor has a maximum speed limit of 7000 rpm.\u00a0 We guessed a primary tube length of 30.00 inches to get the ball rolling.\u00a0 Here\u2019s the math.<\/p>\n

Header Primary Tube Size<\/b><\/p>\n

The equation is: \u00a0\u00a0Diameter<\/i> = \u00a0\u221a((cubic inch displacement \u00d71900)\/(tube length x rpm))<\/strong><\/p>\n

Let’s plug in our numbers:<\/p>\n

Diameter = \u221a((402 \u00d7X<\/strong>1900)\/(30 x \u00d7<\/strong>\u00a07000))<\/strong><\/p>\n

Diameter = \u221a((763,800)\/(210,000)) \u00a0\u00a0=\u00a0\u00a0 \u221a \u00a03.6371428 =\u00a0 1.9071294 inches or <\/strong>
\n2.00″ rounded off to the next largest available tube size<\/strong><\/p>\n

Length<\/i>\u00a0 = \u00a0Cubic inch displacement X 1900\/2 x diameter x RPM<\/strong><\/p>\n

= 402 \u00d7<\/strong>\u00a01900\/2 \u00d7<\/strong>\u00a02 \u00d7<\/strong>\u00a07000 \u00a0= \u00a0\u00a0763,800\/28,000\u00a0= \u00a027.278571 inches<\/strong>
\n or 27.25 inches (rounded off to the closest\u00a0available size)<\/strong><\/p>\n

In the event that the primary tube diameter had been rounded off to 1-7\/8 inches or 1.875 inches, the basic formula would have worked out to the following:<\/p>\n

= 402 \u00d7<\/strong>\u00a01900\/\u00a02 \u00d7<\/strong>\u00a01.875 \u00d7<\/strong>\u00a07000 \u00a0=\u00a0\u00a0763,800\/\u00a026,250 \u00a0= 29.097142 inches, or rounded off to 29 inches.<\/strong><\/p>\n

Collector Length<\/b><\/p>\n

By varying the length of the header collector, you can also adjust the basic power band of the engine.\u00a0 If your combination needs more low-end torque, you should increase the header collector length.\u00a0 If the combination needs less low-end grunt, shorten the collector. To get the right collector length, you really don\u2019t need to crunch numbers. Instead, you need a good old-fashioned crayon or grease-marking pen.<\/p>\n

Simply draw a thick line down the length of the collector using a crayon or grease-marking pen.\u00a0 Make a normal hard pass with the car and check out the crayon mark.\u00a0 The temperature of the exhaust gasses within the collector will cause the mark to discolor or burn at a specific location on each collector.\u00a0 You can shorten the collector at this point.\u00a0 Just be certain to leave an inch or two of added material for further fine-tuning.\u00a0 It’s tough to add material to the collector once it’s been cut.\u00a0 If you find that your racecar “needs” more collector, then you simply add it with an extension kit. .<\/p>\n

How do you know if the car needs more collector length?\u00a0 Watch the crayon mark along with the ET slip.\u00a0 If the crayon mark doesn’t discolor or burn, then the collector is too short.\u00a0 In addition, if the car needs more bottom end grunt and doesn’t “leave” well, then you might be able to use more collector length.<\/p>\n

Now the catch (there always has to be at least one, right?):\u00a0 No matter how nice the pipes look on paper, the header builder is always faced with compromises.\u00a0 In some cars, there simply isn\u2019t room to make headers that are the right size, the right length and with primaries of equal length. As the folks from ARH point out, it\u2019s easy to build \u201cperfect\u201d headers for something like a dragster.\u00a0 There\u2019s nothing in the way.\u00a0 But try that with something like a huge-by-large displacement big block shoehorned into something with honking shock towers (many Mustangs and 3rd<\/sup> generation Camaros come to mind).\u00a0\u00a0 It\u2019s tough enough to squeeze a 2-inch (diameter) header into some combinations, let alone a 2-3\/8 or 2-1\/2 inch job.\u00a0 That\u2019s where science is tossed out of the window and compromise enters the equation.<\/p>\n

As you can see, the science of headers isn’t exactly cut and dry.\u00a0 More often than not, it becomes a game of test and try.\u00a0 That\u2019s why you pay good money for good headers.\u00a0 The manufacturer has done much of the work for you (that certainly isn\u2019t the case with universal, fits-all headers).\u00a0 In the end, you really do get what you pay for.<\/p>\n

\"Once<\/a>
Once header primary length is established (either by the manufacturer or by way of an adjustable race header), you can work with the collector length your car (not just the engine) demands. Draw a thick line down the length of the collector using a crayon or grease-marking pen. Make a normal hard pass with the car and check out the crayon mark.<\/figcaption><\/figure>\n

 <\/p>\n

\"The<\/a>
The temperature of the exhaust gasses within the collector will cause the mark to discolor or burn at a specific location on each collector. You can shorten the collector at this point.<\/figcaption><\/figure>\n

 <\/p>\n

———————————————————————————————————————————————<\/p>\n

So You Want to Be A Drag Racer: Buying, Building, Wrenching and Racing<\/strong><\/em><\/p>\n

The allure of the drag strip is easy to understand \u2013 a place where \u00a0it takes less than 10 seconds to make a stand, prove your skill, speed, and nerve.\u00a0 But the road to the races can be intimidating.\u00a0 The Burnout wants to make that road a lot smoother for aspiring racers, whether it\u2019s through building a new car, modding a used one, or taking that ride all the way up to the burnout box and beyond.\u00a0 This series is a work in progress, an ever expanding comprehensive guide to all the things that take drag racing from concept to reality.<\/em><\/p>\n

Want to chat about this on social media? Use #RJDragRace on Facebook or Twitter<\/p>\n","protected":false},"excerpt":{"rendered":"

Drag Race 101:\u00a0Headers, Part IV Recall a few posts back, \u00a0when we mentioned formulas and software that can help to figure out header dimensions?\u00a0 We\u2019ll, […]<\/a><\/p>\n<\/div>","protected":false},"author":20,"featured_media":7685,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"_jetpack_memberships_contains_paid_content":false,"footnotes":"","jetpack_publicize_message":"","jetpack_publicize_feature_enabled":true,"jetpack_social_post_already_shared":true,"jetpack_social_options":{"image_generator_settings":{"template":"highway","default_image_id":0,"font":"","enabled":false},"version":2}},"categories":[3448,5014,11,3698,9],"tags":[1225,961,1205,1250,1164,461,321],"class_list":["post-7680","post","type-post","status-publish","format-standard","has-post-thumbnail","hentry","category-drag-race-101","category-exhaust-headers","category-how-tos","category-tech","category-tech-tips","tag-collector","tag-drag-race-101","tag-exhaust-valves","tag-header-equations","tag-headers","tag-tech-tips-2","tag-wayne-scraba"],"jetpack_publicize_connections":[],"jetpack_featured_media_url":"https:\/\/www.racingjunk.com\/news\/wp-content\/uploads\/2014\/08\/Header-7Feature.jpg","jetpack_shortlink":"https:\/\/wp.me\/p42YSK-1ZS","jetpack_sharing_enabled":true,"amp_enabled":true,"_links":{"self":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/7680","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/users\/20"}],"replies":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/comments?post=7680"}],"version-history":[{"count":7,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/7680\/revisions"}],"predecessor-version":[{"id":7982,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/posts\/7680\/revisions\/7982"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/media\/7685"}],"wp:attachment":[{"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/media?parent=7680"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/categories?post=7680"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.racingjunk.com\/news\/wp-json\/wp\/v2\/tags?post=7680"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}