[Steve C.]

Two interesting tid bits from Harold Brookshire. The second one posted by Jay Stukenholtx within another Pontiac forum in a related discussion. Note Harold's last comments there.

I no longer have the original computer that designed the original VooDoo cams in 2004-2005. Holley kept that, and it was not returned to Lunati.
However, I have designed some fill-in cams for Lunati, and what I call my 'post-VooDoo' cams, that have proven very successful since 2006.
I call these 'post-VooDoo' because I do not remember the*exact*numbers I used in the ramp designs.
However, the 'seat' durations were chosen by the marketing division of Holley.
We did dyno-test all hydraulic VooDoos against their equivalent Xtreme Energy counterparts.
At 2500, where the tests were started, all VooDoos made more torque than the Xtreme Energy cams. One would think that more bottom-end torque meant a shorter duration,*WHERE IT COUNTS!!!!.
Here are some numbers from my work of the past 3 years.
Hydraulic Intensity (.004" to .050")---53.88 degrees.
The opening side of the Hydraulic Intensity---45 degree equivalent.
The intensity from .006" to .050"---46.00 degrees.
The opening side of .006" to .050"---41.00 degrees.
Remember, the engine sees not ONE number as the duration of the cam, but instead*ALL*numbers on the cam.
The numbers govern how the cylinder fills with clean air/gas, and on the exhaust, how it gets the old exhaust out.
They work together to produce their results.
Just because 2 cams agree at either .006", or .050", does not mean they flow the same amount of air, or make the same torque or BHP.

UDHarold
2009

Both Harvey and I design Unsymmetrical cams, where the opening side and the closing side are different everywhere except at the nose, where we match both sides through the 3rd derivative, at least. We both use different off-sets, the difference between the opening and closing sides, even at .050".
My old 288R that I designed in April, 1980, thought it was a 282 at .020 when it opened, a 252 at .050. Then it knew it was a 258 at .050 when it closed, and 294 at .020, still closing. The 288R was notorious for bottom-end torque, and good power everywhere. It had 176 at .200, one degree more than the Crane R260/4167.
What I use now is the R255416H. This rascal thinks it is a 279 at .020 when it opens, still a 252 at .050, still a 258 when closing, and now a 288 at .020. At .200, 180 degrees. I've lost 5 degrees at .020, kept the same duration at .050, and gained 4 at.200. It has gained power everywhere.

Remember, it is not WHAT the duration is, but WHERE the duration is, that counts in camshafts. Remember, the engine sees WHERE the duration occurs, not WHAT the duration is.

UDHarold



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