Exploring Weak Points of the RAM TRX Hellcat Engine

Exploring Weak Points of the RAM TRX Hellcat Engine

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    The RAM TRX is a powerful truck with an impressive Hellcat engine that can easily achieve high horsepower numbers without extensive modifications. However, even with its strength and durability, there are still weak points that can be found, as discovered during a teardown of a customer's TRX engine making 1000HP.

    When removing the old rods and pistons to install a forged rotating assembly, it was found that cylinder number 3 had issues sliding out of the bore smoothly. Further inspection revealed a small portion of the ringland had been dented due to a pre-detonation event, causing material transfer to the cylinder wall.

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    Although there was no major damage to the engine, this issue was not surprising as data collected from 8+ TRXs from numerous shops and some of our in-house builds showed a similar pattern across cylinder 3 on the TRX Platform specifically. Knowing this, we already suspected cylinder 3 to be the most prone to damage. However, pushing the stock engine to 1000HP requires being mindful of two main things: cylinder 3 misfires/knock under heavy loads and phaser walk.

    The cam phaser is a component of the variable valve timing (VVT) system used in the Hellcat engine. The VVT system allows the engine to adjust the timing of the intake and exhaust valves, which can improve performance and fuel efficiency. The cam phaser is a gear mounted on the end of the camshaft and is designed to rotate the camshaft slightly in relation to the crankshaft, allowing for the timing of the valves to be adjusted. The cam phaser is controlled by the engine control module (ECM), which uses input from various sensors to determine the optimal timing for the valves.

    Phaser walk refers to a condition where the camshaft is not rotating as it should, leading to a misalignment of the camshaft and crankshaft. This can cause reduced performance and increased engine wear. To address this issue, we added forged rods and pistons, coated bearings, and ported heads to help with airflow. We also included a phaser lockout as an additional safety measure, as similar issues have been seen on other platforms when reaching high horsepower.

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    Although finding unsuspected damage during an engine teardown can be an unpleasant surprise, it can be anticipated and addressed early before major engine damage occurs, resulting in a more pleasant automotive experience. In this case, we caught it and addressed it before the engine was severely hurt.
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