Terry,
Our cam is 181deg at .050" .280" lift compared to factory 159 deg T .050" .235" lift. Our exh is 210 deg at .050" and .307" lift compared to 191 deg at .050" .298 lift.
The main difference in our cams and our competitors is that our exhaust stays closed longer. This keeps the still burning fuel pushing down on the piston longer. The other guys typically release the exh. sooner. This is how they get improved spoolup, they use the pressure that should be busy pushing on the piston still, to push on the turbine wheel. THis diminishes efficiency, reduces fuel economy potential and raises EGT's. Because of the greater exhaust flow with this method you also have much greater drive pressures at high rpm. so it is important to have loose turbine housings large turbine wheels and large gates to handle the extra flow. These cams need perfect balance of drive pressure to operate efficiently.
Because of our fast ramp rates and our intake placement, we get greatly improved spoolup but we also maintain maximum efficiency, fuel economy, and egt reduction. Our cams usually have a smooth and more linear power curve whereas others usually "come on hard" at a certain RPM. If efficiency is of no concern we have cams that come on much sooner and stay on much later in the rpm band But once again your have to know what your drive pressures are for it to work correctly.
A side note to the importance of controling drive pressure.
If you increase your drive pressure 10psi that exact force is pushing down on your 4.020" piston (12.69 square inches) creating 126.9 lbs of force. 126.9lbs X the 4.72" stroke = 599inch/lbs divide that by 12inches and you get 49.9ft/lbs. Now muliply that by 6 cylinders and wow 299ft/lbs of parasitic loss. This is why it is so important to keep your drive pressures in check! If that 10psi drive pressure increase comes with an extra 20psi of boost, you are on the plus side, as long as you have enough fuel for that extra air. If you have already cleared up all your smoke, and cooled your egt's, then creating tons more boost and much more drive pressure is a great way to waste a lot of Rear wheel Horsepower. This is how we can make almost 1000hp with only 50-56psi of boost, while others are at 100psi to make similar hp, efficient cam with low drive pressures.
Zach Hamilton
