Quote:
Originally Posted by DSGcoupe
Interested to see what some of the knowledgeable people on this forum think.
I have seen them in circle track engines and a few of those guys around here swear by them, but have never used one personally. I have always preferred to put the time into balancing out the intake flow with the carbides and testing. In theory, it makes some sense; but I am looking to see if anyone actually has any first hand experience with them.
So, are 4 pattern cams just Black Magic/ snake oil or are they legit and based on sound testing? |
I like 12-pattern cams where six of the eight cylinders get different patterns. Two are almost the same but not, and three use counter-rotating patterns. The other seven are tied to the air speed in their individual ports, factored by their linear distance, measured in SI units, from the car’s center of gravity with a half-full tank of gas. This modifier is necessary because of the lateral effect on the car's CG. The gas in the tank needs to have a minimum specific gravity of 0.693.
The remaining four cams use custom 5-cycle dynamically configured ramp profiles and therefore velocities, again factored by their distance (this time in Imperial units) from the car’s CG. Be sure when you take the measurements this time, you do it with a three-quarter full tank of gas.
This type of valve event requires the use of a hybrid fuel delivery system. The design incorporates a Holley 850 double pumper with two of the diagonal squirters disabled, blocked-off main jets with operating power valves, and individual port injection installed in each manifold runner.
For the ECU, you will want to use a Motec custom M1 ECU with their multicylinder Pro Analysis upgrade. This upgrade is available for the current version of MoTeC's i2 data analysis software to provide advanced mathematics, multiple overlay laps, and unlimited components, workbooks, and worksheets that will allow you to correctly phase each of the counter-rotating patterns vis-à-vis the nine non-counter rotating cams.
Properly configured, you will experience engine operating events, unlike anything you ever have previously known.