1. The pressure relief device for the tensioner has been upgraded from a regular air bleeder plug to a relief valve, which maintains constant damping in the high-pressure chamber of the operating tensioner in idle or high-RPM state of the engine, and therefore leads to more stable product performance.

2. The material has been changed from cast aluminum to HT250 cast iron, which contributes to higher structural rigidity of the product.

3. The plunger piston diameter has been increased, leading to larger contact area between the tensioner and the guide rails and higher stability.

4. The plunger spring is subject to enhanced treatment for better fatigue resistance.