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Old 02-04-2014, 05:14 PM   #71
Pro Stock John
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Originally Posted by dan0617 View Post
very inefficient to put a large overlap cam on a blower setup. On an all out race car and a huge blower you might pick up some top end power with some added overlap. I'll give you that. But I stick by what I said. If you are using cam overlap to control cylinder pressure on a boosted engine you are not doing your build right. Pick the cam to go with your blower, converter, gears, intake, cubes, heads, etc. Set the SCR to control cylinder pressure and temps, along with octane and meth or race fuel.
Yeah it all depends on the context.

For a race car we'd run the cam that yielded the best results for a given combination. That might be a cam with a lot of overlap but it's the result also of just running a bigger cam with more duration.

I know of some race cams running really big splits (between the intake and exhaust duration). Cams are picked to work with the power adders, valve train limitations, and the cam designer in theory is looking for the best balance between peak HP and the power under the curve.

If you are building a class car with a blower for example, let's say you could run a YSi or F1C or Novi 2000, you'd be taking into account a lot of variables.

Increasing duration will increase peak power but tend to shift the power band higher.

For some good reading search on 'Richard Holdener' he did a bunch of LSx articles for Hot Rod and other sister mags. He mixed and matched a lot of parts and the results are interesting.

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edit:

Camshafts are part of the overall equation, including the power adder selected, gearing, weight of the ride, what the heads flow on the intake and the exhaust, the fuel that will be used. So I'd say it's not a good idea to generalize about camshafts.

Heck the cam that makes the best peak HP might be a dog at the track and/or from an acceleration standpoint.
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Old 02-04-2014, 05:28 PM   #72
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A cam/CR/boost/timing/fuel/ combination chart for different builds to BHP would be an awesome thing to look at. Make it easier to figure out a build.
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Old 02-04-2014, 06:07 PM   #73
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A cam/CR/boost/timing/fuel/ combination chart for different builds to BHP would be an awesome thing to look at. Make it easier to figure out a build.
Charts and graphs are great. Then you throw in personal wants, needs, expectations, etc. Cams are a big compromise. A cam that makes you all school girl giddy might not do it for me. My new 224/234 116+2 is perfect for my wants and needs ( I think...haven't run it yet). If you were wanting a cam for the exact same rig as mine, the perfect cam for you would probably be totally different. That right there is what intrigues me about a damn camshaft. Lots of variables to think about
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