Monster-Ram Vs. Black Market

RAM 6.7L owners have choices when it comes to preventing grid heater bolt failure. But one option that should not be on anyone’s list is from Black Market Performance, aka BMP. While the BMP 6.7 Cummins Open Grid Plenum offers the allure of eliminating the failure-prone factory grid heater, it results in a loss of horsepower. Yes, with this installed, your engine will lose horsepower.

Everyone knows the stock intake elbow and grid heater is incredibly restrictive. (Gale has proved it in various videos). While this is true, the BMP kit is worse. The intake plenum (Cummins part # 4930917) is found on constant-duty Cummins QSB industrial engines used in applications like generators. In other words, these engines are designed to run at a single RPM. Rated for 130-275hp, they require less air mass than those used in automotive applications. 

We wondered, “Is it as restrictive as it looks?” So, we purchased one and tested it on the flow bench. Then, for accuracy, we tested the stock intake elbow with the factory grid heater, and the Banks Monster-Ram with high-flow billet intake plate, all in the same session, on the same morning. The average RAM 6.7L engine flows 50 pounds per minute so that’s where we tested them. 

Here’s what we found. Thanks to the harsh 90 degree bend, hard edges, and 1/4″ step where the tube meets the intake plate, the BMP kit flows almost 33% less air mass than stock (shown below). In other words, the engine loses boost pressure with the Black Market elbow. Your turbo will be working harder to push the air passed the newly introduced restrictions. The result is mushier throttle response and less power. Watch the flow bench tests here. 

Taking a closer look at the Banks Monster Ram, difference between it and the stock elbow is undeniable. The Monster-Ram’s outlet is more than twice the size of the stock outlet. The casting is so massive that we had to engineer a new #1 fuel line to jump over the Monster-Ram. Every aspect of the Monster-Ram has been engineered for superior airflow. Using computational fluid dynamics, our engineers turn the air 180° while increasing its mass. Gale Banks hales this as one of his best achievements. 

The secret to the Monster-Ram’s performance is not just airflow, but the quality and literal weight of the air it flows. Your Cummins engine is limited in the volume of air it can flow through its 6 cylinders even at max RPM. However, the engine is not limited when it comes to air mass—there’s ample overhead to take advantage of, which Gale explains here. By increasing the mass of the air delivered to each cylinder, your stock-tuned engine will breathe more efficiently with less stress and set the stage for huge power gains when stacked with a tune.