COMP Cams

A long time ago racers identified a major problem with intake manifold designed for four-barrel carburetors on V8 engines and that's unequal air flow. You see whether it's a dual plane or a single plane design, the air is always going to have to take a different path between the center cylinders and the outboard cylinders. Now in NASCAR a lot of time and a lot of energy has gone into minimizing this problem with special patterns for cam shafts but this technology hasn't always made it down to the cons Now Comp says that compared to a conventional hydraulic cam with similar specifications their four-pattern cam is going to give you between 5 and 20 more horsepower. Now it's going to cost you a little bit more than a conventional cam but it's well worth it to bring t First the NASCAR connection starts with the construction. As you can see these cams are CNC machined from Billet Steel just But there's one big difference. As Using hydraulic lifters gives the Comp engineers much more flexibility in designing aggressive cam lobes and optimizing the valve overlap. Due to uneven runner lengths the vol The four center runners of any single four barrel intake are shorter in length. The difference averages about 10% that's enough to create a measurable airflow imbalance. Comp engineers tested many intakes and most showed lean outboard cylinders at low engine speeds w To give you a little bit more insight here's Billy Godbolt of Comp cams. A lot of people understand in general the idea of dual pattern cam shafts. We have a different lobe design for the intake and exhaust. Clearly you're trying to pull in the intake charge where the exhaust charge escapes a lot of months on you're pus So moving the timing events from intake to exhaust makes a lot of sense. However people don't understand that when you get to a common configuration V8 with the central mounted throttle body you have long runners on the outboard cylinders and short runners on the inboard cylinders. Therefore you've really got two different engine configurations. Every V8 engine is really a combination of eight engines put together. So on those four outboard cylinders they're going to have different needs than the four inboard cylinders. And that trying to address that issue was the genesis of the four pattern cam shaft. Now here's a brief overview of the four pattern concept. The inboard cylinders all have the same grind that is the same duration and valve lift. The big difference comes with the outboard cylinders where the intake closing is delayed by two degrees. There's also a little bit more duration to give those cylinders additional air. Air turns very easy inside a manifold but fuel does not. So at low RPM where the outboard cylinders are working hardest they bring in more air but they bring in about the same amount of fuel as the shorter cylinders. So those cylinders wind up running very lean w The lobes in blue control the intake valves for the outboard cylinders w The exhaust profiles shown here in yellow and green are not only different than their respective intake valves they also differ between the inboard and outboard cylinders to help even the air flow. The comp strategy gives the cylinders with longer runners more duration and a later intake closing to move the same vol The shorter runners need less duration and earlier intake closing events to balance the air flow vol In addition comp implemented two new technologies into the four pattern cam shaft. One new lobe designs provide more aggressive valve events and hydraulic roller applications. Two comp optimized overlap and lobe separation for unequal length runners. The end result is more power to your engine. Finally to give the customer a clear guide to the lobe profile comp not only provides a cam card but also a full ADCOL certification.