Comp's "variable cam timing"...
Comp's "variable cam timing" provides an ability to determine best torque for each camshaft position (relative to crankshaft angle). Once this is determined, a final "curve" will be produced that essentially boosts torque above and below the original peak torque rpm point.
As previously indicated, electronics play a major role in this issue. Given the fact it's possible to modify the stock camshaft phasers in engines that incorporate this technology, proper control of their function is key to optimizing power, at both lower and higher rpm. Specifically, computer programming should include addressing the cam retard limiting issue, along with provisions (for street-driven engines) to make certain diagnostic trouble code (DTC) strategies are properly restored. For racing applications, this latter issue is not a concern.
In addition, Comp provides "phaser limiters" that prevent cam retard positions from exceeding 20 degrees, at least for the 4.6- and 5.4L Three-Valve Ford engine. Looking ahead, this same approach is anticipated for other computer-controlled engines for which they plan producing camshafts. And in that regard, you can expect some form of "electronic device" as a companion to any race-bred camshafts Comp offers for circle track applications.
At the time of this writing, Comp is aggressively exploring application of the technology in GM's LS engine family. Given the fact these are and continue to become "spec" engines in the circle track community and GM's inclusion of cam phasing technology in them, Comp is currently evaluating prototype units directed to circle track use. Again, by limiting the extent of OEM camshaft retard, racing camshaft lobe profiles and valve timing can be developed that optimize torque boosts below and above an engine's peak torque rpm, thereby improving both off-corner acceleration performance and straightaway speeds in circle track applications.
Here you can see COMP's "Phaser...
Here you can see COMP's "Phaser Limiter Kit" installed in an otherwise stock Ford 4.6-5.3L cam gear. The same concept is already under development at COMP for the LS series of GM "small-block" engines for circle track application.
Virtually any race engine is a combination of compromises. Over time, engine builders have incorporated various techniques to "flatten" or "broaden" torque curves, particularly for applications in which a comparatively wide range of engine speed is required. Especially well suited to circle track engines required to operate over a span of 3,000 rpm or more, the ability to dynamically alter camshaft/crankshaft relationships appears to be a significant step toward minimizing power losses and extending an engine's operational range.
Of particular interest is the fact this technology addresses the time-honored problem of advancing and retarding camshafts when deciding upon where to optimize and where to compromise power gains (or losses). Not only does the prior practice tend to consume inordinate amounts of dyno time, excluding engine wear, it's essentially a trade-off in terms of selective power placement. Given the ability of Comp's concept, it's possible to perform a series of tests (specifically eight) at different camshaft advance locked positions to determine optimum power. Then it's a relatively simple matter to remap the controller's program to incorporate these settings over a span of rpm, thereby eliminating the time-honored "advance compromise" by present-day methods. Essentially, this process of reprogramming the phaser ensures the cam will be at its best power output levels throughout the desired rpm range, not within a narrow span.
Finally, as we move toward electronic valvetrains and "cam-less" engines, the incorporation of variable cam phasing techniques (although initially enabled by the OEM) looks to be an intermediate step to the removal of camshafts altogether. And since it stands to be a while before we get to that point, COMP's "variable cam phasing" packages may be the answer to engines benefitting from enhanced torque both below and above torque peaks. What's the old saying about "having your cake and...?"