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The HEMI engine has become a staple in the performance automotive community, particularly the 6.4L variant found in various Dodge and Chrysler models. One of the popular modifications among enthusiasts is the MDS (Multi-Displacement System) delete, which can lead to significant performance gains. In this article, we will explore the differences between a stock 6.4L HEMI and one with the MDS delete, focusing on the rear wheel horsepower gains.
Understanding the HEMI Engine
The 6.4L HEMI engine is known for its robust performance and power output. It features a unique hemispherical combustion chamber design, allowing for better airflow and combustion efficiency. This engine is equipped with the MDS, which deactivates half of the cylinders under light load conditions to improve fuel economy. However, this system can also hinder performance during spirited driving.
What is MDS and Why Delete It?
The Multi-Displacement System (MDS) is designed to enhance fuel efficiency by shutting off four of the eight cylinders when the engine is under low load. While this can improve gas mileage, it can also lead to a noticeable lag in power delivery and responsiveness when the driver demands more from the engine. For performance enthusiasts, the MDS delete is a popular modification that allows for continuous operation of all eight cylinders, resulting in increased horsepower and torque.
Benefits of MDS Delete
- Improved throttle response
- Increased horsepower and torque
- Elimination of potential engine lag
- Enhanced engine sound
- Better overall performance during acceleration
Performance Gains: Stock vs. MDS Delete
When comparing the stock 6.4L HEMI with the MDS system activated against one that has undergone the MDS delete, the differences in performance can be quite substantial. Enthusiasts have reported rear wheel horsepower gains of over 40 horsepower after removing the MDS system.
Stock 6.4L HEMI Performance
The stock 6.4L HEMI engine typically produces around 470 horsepower and 470 lb-ft of torque at the crank. However, due to drivetrain losses, the rear wheel horsepower (RWHP) is usually around 390-410 horsepower. The MDS system can create a slight delay in power delivery, especially when transitioning from low to high throttle inputs.
MDS Delete Performance
After performing an MDS delete, many users report a noticeable increase in rear wheel horsepower. With the MDS system removed, the engine runs more efficiently, and drivers can expect to see RWHP figures exceeding 430 horsepower, depending on additional modifications and tuning. This increase is attributed to the elimination of the MDS lag and the ability to utilize all eight cylinders at all times.
Factors Influencing Performance Gains
While the MDS delete can lead to significant performance gains, several factors can influence the overall results. These include:
- Quality of the MDS delete kit
- Engine tuning after the delete
- Additional modifications (exhaust, intake, etc.)
- Vehicle weight and drivetrain components
- Driving conditions and style
Considerations Before MDS Delete
Before deciding to perform an MDS delete, there are several considerations that potential modifiers should keep in mind:
- Warranty implications: Modifying the engine can void warranties.
- Fuel economy: While performance increases, fuel economy may decrease.
- Potential emissions issues: Ensure compliance with local emissions regulations.
- Cost of modifications: Factor in the cost of parts and labor.
Conclusion
The comparison between a stock 6.4L HEMI and one with the MDS delete highlights the significant performance advantages that can be gained from this modification. With over 40 rear wheel horsepower gains, the MDS delete not only improves acceleration but also enhances the overall driving experience. For those looking to maximize the potential of their HEMI, the MDS delete is a modification worth considering, provided that the associated implications are understood.