The Complexity of Adding Cruise Control to an Old Car: A Closer Look
Adding cruise control to an old car, especially for someone with limited mechanical skills, can seem like a daunting task. While many modern cars come with this feature, it's not uncommon for older vehicles to lack it. This article explores the challenges and nuances of installing cruise control in an older car, offering valuable insights for enthusiasts and DIY mechanics.
The Difficulty for the Mechanically Inexperienced
For individuals with limited experience in automobile mechanics, adding cruise control can be a challenging endeavor. It's often easier to consider trading in the old car for a more modern one equipped with this feature. Yet, for those who find joy in owning older cars and appreciate the satisfaction of making them better, the process is worth the effort.
For instance, my first boss, who joined me 30 years ago, installed one of the early kits available for UK-manual cars, and it worked flawlessly. The kit operated by detecting electromagnetic pulses from the engine’s ignition system, altering the pedal position to match the engine’s rate, with minimal disconnection of wires.
Modern Cars and Cruise Control
These days, most modern cars utilize a “drive-by-wire” system, meaning there is no direct physical connection between the accelerator pedal and the engine. The cruise control is integrated into the engine’s management computer, which reads a resistance value from the pedal. This sophisticated system requires a higher level of mechanical and electronic knowledge to install.
Choosing the Right Kit
To successfully add cruise control, one will require some above-average mechanical skills. Rostra offers a high-quality aftermarket kit that can provide a factory-like appearance, especially if you can use the turn signal stalk. However, installing the kit necessitates access to the vehicle’s wiring diagram to source the necessary connections for battery power, ground, VSS (Vehicle Speed Sensor), brake lights, and clutch signals. For manual transmissions, this also includes the throttle cable.
The most critical aspect of the installation is properly attaching the throttle cable, as any issues here can result in the throttle sticking in an open or closed state. Additionally, if using a stalk switch, the wiring must be routed through the steering column.
Older Car Considerations
When fitting aftermarket units to older carburetted cars with simple cable or rod-operated throttle linkages, the kits are generally straightforward. Basic functionalities like canceling, resuming, increasing, and decreasing speed involve simple electrical connections, often into the brake light circuit. Some of these kits may not even be able to apply the brakes to maintain the set speed while going downhill or adjusting speed behind a slower vehicle.
As an example, a rental car I evaluated recently featured a more advanced system where the cruise control adjusted speed automatically when overtaking slower-moving trucks and then resumed set speed. This complexity, driven by modern computer-controlled systems, presents a stark contrast to the basic functionality of older kits.
Challenges and Solutions
The most challenging part of the installation process is attaching a small magnet to the driveshaft, which must be done with extreme care to prevent it from coming loose or being thrown off by centrifugal force. Despite this, even installing this magnet onto a front-wheel-drive vehicle’s driveshaft presented a unique challenge, and I managed to accomplish it successfully.
Conclusion
While adding cruise control to an old car is not without its challenges, it can greatly enhance the driving experience. For those who are mechanically inclined and willing to invest time and effort, there are a variety of options available, from basic kits to more sophisticated systems. The journey of installing cruise control in an old car can be a rewarding one, offering a blend of mechanical satisfaction and modern convenience.