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Experience the difference with MPI Exhaust’s patented pulse chamber. Guaranteed no drone.

MPI Exhaust integrates our Patented Pulse Chamber Technology (PCT) in all complete kits, delivering a guaranteed drone-free experience whether you're driving casually or heavy towing. This technology maintains a mellow cabin environment, even with our Aggressive series mufflers, so you can enjoy a smooth, but improved sound.

What Causes the Drone?

What Causes the Drone?

Exhaust drone occurs due to an imbalance in the lengths that exhaust pulses travel. As these pulses cover different distances, their amplitudes vary. When the left head pipe has a longer travel distance than the right head pipe, the unequal pulses cause in-cab droning most common at 1500-1700 RPMs. Our patented pulse chamber resolves this by merging these varying amplitude pulses into a single chamber balancing the unequal pulses, eliminating any chance of a drone.

What's an Exhaust Pulse?

What's an Exhaust Pulse?

An exhaust pulse refers to a concentrated burst of gases that are expelled from the combustion chamber when the valve opens. Instead of flowing continuously and smoothly, the exhaust gases travel in distinct pulses. In the case of a V8 engine, it produces 8 exhaust pulses for every revolution. At 3,000 RPM, this means there will be 24,000 pulses moving through the system.

For example, in a single-cylinder engine, you can Hear or feel the inductive pulses when running, the same effect occurs with 8 or more cylinders.

PULSE CHAMBER FAQ

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Why doesn't my factory truck exhaust have a drone?

The factory system eliminates in-cab drones by creating significant back pressure, which tightly stacks the exhaust pulses, thus minimizing the drone. However, this approach reduces engine performance and increases under-hood temperatures, leading to decreased exhaust manifold life. This method is still used in a majority of other aftermarket systems, which is why they see no performance gain compared to the stock configuration.

Our patented pulse chamber balances exhaust pulses, enabling us to open the exhaust to the optimal size for maximizing engine efficiency while maintaining a quiet, drone-free experience, as demonstrated by our unmatched dyno results.

What's the difference between an "H-Pipe" and Our Pulse Chamber?

The term "H-pipe" refers to a short pipe that connects both sides of an exhaust system, typically positioned perpendicular to the exhaust flow, forming an "H" shape. This design was widely used in vehicles from the late 1950s to the 1980s, with the belief that it would enhance low-end torque by balancing the exhaust flow between the two engine banks. However, while the H-pipe could offer some benefits in this area, it also introduced drawbacks. The turbulent flow within the H-pipe often led to more restrictions, which would reduce performance. Additionally, H-pipes provided minimal help in reducing in-cab noise or droning.
At MPI, we've addressed these limitations with our patented Pulse Chamber design. This innovative approach eliminates the turbulence and restrictions commonly found in H and X pipe configurations. After conducting thousands of tests, we've achieved a design that not only maximizes performance but also guarantees no droning. Our Pulse Chamber ensures a smoother, more efficient exhaust flow, providing a clear advantage and no need to worry about the false claims of other options.