We developed our range of blown camshafts to maximise the available boost in blown applications. Our custom grind Joe Blow camshafts are blower specific camshafts, developed for use in blown applications. These differ from both normally aspirated and turbo camshafts and are designed to help you make the most of your available boost.
This is our JB400 grind - For larger capacity engines, our all out race cam. More lift and duration than the JB300. Requires good heads and lots of boost. 465″ lift / 313 degrees duration on a 112 L/C
Why do I need a blower cam?
Many people will recommend turbo and N/A cams for blown applications. Whilst these cams will certainly be an improvement over the stock cam, they are less than optimal in a blown application and will not maximise the use of available charge, resulting in lower dynamic compression ratio, which results in lower cylinder pressures and in turn less power.
Turbo cams are generally split duration with larger lift on the inlet to help overcome the high back-pressure ratio. This back-pressure comes from having the exhaust drive the turbine and causes the exhaust port pressure to be higher than the inlet pressure. On a blown engine there is no turbine to drive and so the inlet port pressure is higher, basically the opposite to a turbo. This means that turbo cams are not really a good fit for a blown application as the valve dynamics are incorrect.
Likewise N/A cams have narrow lobe separation angle resulting in a lot of overlap (the portion of the cycle where both inlet and outlet valves are open at the same time). In an N/A engine this overlap assists with cylinder scavenging where the exiting exhaust gasses help draw in the intake charge. Unfortunately having both inlet and outlet valves open at the same time on any forced induction setup results in the pressurised intake charge simply being pushed straight out of the exhaust port. Boost will not start to build in the cylinder until the exhaust port is closed.
We found that there was nothing available specifically for blown applications and so this is why we developed our own range of blower cams. Our cams will work on all blown installation, not just ours. All of our cams are custom ground for us by Engle, so you know you are getting a quality product.