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I would rather be driving
Join Date: Apr 2000
Location: Austin, TX
Posts: 9,108
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HMM I guess my post after the first set of (as you say wrong) calcs never made it to the server. These look much better. I was working through them and got a soln similar to what you have here.
This is great information.
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Jamie - I can explain it to you. But I can not understand it for you. 71 911T SWT - Sun and Fun Mobile 72 911T project car. "Minne" - A tangy version of tangerine #projectminne classicautowerks.com - EFI conversion parts and suspension setups. IG Classicautowerks |
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Join Date: Feb 2004
Location: California
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When changing to a longer rod I like to reduce the overall duration and widen the lobe centers. Usually a 2 degree wider change in lobe centers and up to 5 degrees less duration.
The problem with available 911 camshafts is there big jump from one grind to the next. Unless a custom ground set is made the only change you can easily make is the lobe centers.
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John Dougherty Dougherty Racing Cams |
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Quote:
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joe ------------------ '69 911 E Targa - aka "RoxiE" |
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Location: California
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Take the duration at 1mm for the intake, 266 degrees. divide by 2 and subtract the intake centerline.
266/2=133. 133-102= 31. We find the intake valve opens 31 degrees before top dead center. Now do the exhaust side. 249/2=124.5. 124.5-102=22.5. The exhaust valve closes 22.5 degrees after top dead center. Add the two events together and you have 53.5 degrees. The amount of time from the intake opening to the exhaust closing. Fwiw, this is the least important parameter to me. I put the 4 most important events where I want them, and let the overlap fall where it may. 4 most important being intake closing, exhaust closing, exhaust opening, and intake opening, in that order.
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John Dougherty Dougherty Racing Cams |
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Quote:
Great thread!!! |
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