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<blockquote data-quote="Trixter" data-source="post: 1988562" data-attributes="member: 542668">well, according to the precision port formula....Lv = [(8466.4 x R^2 / Vb x Fb^2) - 1.463] - 5you&#039;ll need to cut your Vb in half (since you have 2 ports) so Vb = 1.43Lv = [(33865.6 / 1751.75) - 1.463] - 5Lv = (19.33 - 1.463) - 5Lv = 17.87 - 5the subtraction of the 5 is because each flare is 2.5&quot; long. you&#039;ll cut your center section to the Lv figure.but now that we have the length, we need to subtract the port displacement from the Vb and refigure....2 X (Pi R^2) = 12.5612.56 x 17.87 = 224.44224.44 / 1728 = .131.43 - .13 = 1.3our new Vb is 1.3...now redo the math to get....Lv = [(33865.6 / 1592.5) - 1.463] - 5Lv = (21.27 - 1.463) - 5Lv = 19.81 - 5Lv = 14.81so cut your center section to 14.81 (i&#039;d do 14.75 to make it easy) and add your flares.i hope you already accounted for sub displacement, or your Vb will change again. if you accounted for port displacement in the original 2.86 you gave, let me know and i do it agin for you...or you can, now that you have the formula. only use net volume with the sub displacement and then recalculate like i did when you know that port displacement.enjoy<img src="data:image/gif;base64,R0lGODlhAQABAIAAAAAAAP///yH5BAEAAAAALAAAAAABAAEAAAIBRAA7" class="smilie smilie--sprite smilie--sprite6" alt=":cool:" title="Cool&nbsp; &nbsp; :cool:" loading="lazy" data-shortname=":cool:" /></blockquote>

[QUOTE="Trixter, post: 1988562, member: 542668"] well, according to the precision port formula.... Lv = [(8466.4 x R^2 / Vb x Fb^2) - 1.463] - 5 you'll need to cut your Vb in half (since you have 2 ports) so Vb = 1.43 Lv = [(33865.6 / 1751.75) - 1.463] - 5 Lv = (19.33 - 1.463) - 5 Lv = 17.87 - 5 the subtraction of the 5 is because each flare is 2.5" long. you'll cut your center section to the Lv figure. but now that we have the length, we need to subtract the port displacement from the Vb and refigure.... 2 X (Pi R^2) = 12.56 12.56 x 17.87 = 224.44 224.44 / 1728 = .13 1.43 - .13 = 1.3 our new Vb is 1.3...now redo the math to get.... Lv = [(33865.6 / 1592.5) - 1.463] - 5 Lv = (21.27 - 1.463) - 5 Lv = 19.81 - 5 Lv = 14.81 so cut your center section to 14.81 (i'd do 14.75 to make it easy) and add your flares. i hope you already accounted for sub displacement, or your Vb will change again. if you accounted for port displacement in the original 2.86 you gave, let me know and i do it agin for you...or you can, now that you have the formula. only use net volume with the sub displacement and then recalculate like i did when you know that port displacement. enjoy:cool: [/QUOTE]

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