Can Changing the Final Drive Improve Speed?
2 Answers
Changing the final drive can improve speed. Here are the specific details about the final drive: 1. Function: The final drive typically consists of a pinion gear and a ring gear, independently installed on the rear-wheel drive shaft. Its main function is to alter the car's acceleration performance by changing the gear ratio of the final drive, which in turn modifies the car's torque value. 2. Types: Final drives are generally categorized into close-ratio and wide-ratio. Replacing the final drive with different ratios will give the car different performance characteristics and bring different drawbacks. Installing a close-ratio final drive can increase the car's torque output, effectively enhancing acceleration performance. However, a close-ratio final drive will raise the engine's RPM across all gears, thereby reducing the top speed in each gear and causing the engine to hit the rev limiter earlier. Wide-ratio final drives are usually installed in cars with turbocharged engines because turbocharging increases the car's compression ratio, which in turn increases the output torque. In this case, a wide-ratio final drive is used to reduce torque output and increase the top speed in each gear.
Over the years, I've often been asked by friends about differential modifications. It does improve the vehicle's acceleration performance, mainly by altering the gear ratio of the differential to enhance low-RPM acceleration. If you frequently drive in the city or need quick overtaking, this modification will make the car respond more aggressively, such as providing a stronger push-back sensation during take-off. However, I must remind you that this doesn't mean a significant increase in overall speed—top speed might actually be limited because higher RPMs increase engine load and can lead to overheating. Another key point is that fuel consumption will rise; my own car used noticeably more fuel per 100 kilometers after the modification. Additionally, older cars need careful consideration when modifying, as the increased strain on the drivetrain may cause transmission wear or unusual noises. It's advisable to consult a professional shop for an evaluation rather than diving in blindly. Balancing safety and performance is the way to go.
