Black Market Performance RAM Cummins Intake Elbow Is Worse Than Stock

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 Utah's 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, it loses horsepower.

But how could this be? Everyone knows the stock intake elbow and grid heater is incredibly restrictive. 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. Rated for 130-275hp, these engines require less air mass than those used in automotive applications.

BMP paired this Cummins industrial engine intake plate with a piece of bent tubing. We thought, “That looks really restrictive.” 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 lbs 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. In other words, the engine loses boost pressure with the Black Market elbow. Since the turbo has a target boost to hit, it means your turbo will be working harder. The result is mushier throttle response. Watch the flow bench tests here.

Performance parts are supposed to add performance, not take it away. If you want performance and peace of mind, the Monster-Ram is still the reigning champ. The Monster-Ram increases air density by removing unwanted restrictions, resulting in improved throttle response, power and fuel economy.

The difference between the stock elbow and Banks 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.

Outlet size comparison of the Banks Monster-Ram vs Stock

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.

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.

There's a wives' tale that the stock Cummins head is is at its limit, therefor, the Monster-Ram will not improve performance. Watch Gale Banks debunk this myth below.