Converting a Dacia Logan II to an electric vehicle is more than just swapping an engine for a motor—your braking system must also be upgraded. Electric vehicles are heavier than their gasoline counterparts and rely on a combination of regenerative and mechanical braking to slow down. Choosing the right braking system for your converted Logan II is key to ensuring safety, efficiency, and a smooth driving experience. Here's everything you need to know.
Understanding the Unique Needs of Electric Vehicle Braking
The original braking system of the Dacia Logan II is designed for the weight of a gasoline engine vehicle (approximately 1100-1300 kg). Electric conversion adds 150-300 kg of weight (from batteries and motors), increasing inertia and requiring greater braking force. Additionally, electric vehicles use regenerative braking to recover energy, which reduces wear on mechanical brakes but requires coordination between systems.
Weight Increase
Heavier vehicles require stronger brakes to achieve the same deceleration rate.
Regenerative Braking Integration
Mechanical brakes must work in harmony with regenerative systems to avoid delays or jerks.
Reduced Brake Usage Frequency
Regenerative braking handles most light deceleration, so mechanical brakes need to work reliably even after long periods of inactivity.
Disc Brakes vs. Drum Brakes: Making the Choice
The original Dacia Logan II typically uses a front disc/rear drum brake configuration—a cost-effective solution for gasoline models. For electric vehicle conversions, upgrading to a four-wheel disc brake system is strongly recommended, with the following analysis:
Front Brakes
Disc brakes are essential
- Disc brakes dissipate heat better than drums, crucial for handling the majority of braking force (about 60-70% for front-wheel-drive vehicles like the Logan).
- Choose ventilated discs (300-320 mm diameter) to handle heat from heavy braking, such as on downhill sections.
Rear Brakes
Upgrade from drums to discs
- Drum brakes are suitable for light use but are inadequate in heat dissipation and consistency.
- Upgrade to solid rear discs (260-280 mm diameter) to improve braking force and better integrate with regenerative braking.
- For high-performance conversions (e.g., motors over 100 kW), consider ventilated rear discs to match front braking capability.
Key Specifications: Brake Calipers and Disc Sizes
Larger brake discs and calipers generate more friction, but they must fit within the Logan's wheel hub space (typically 15-16 inch wheels). Target specifications are as follows:
300 mm diameter, 25-30 mm thickness (ventilated discs).
260 mm diameter, 20-25 mm thickness (solid or ventilated discs).
Single-piston calipers are sufficient for most conversions, but if you frequently carry passengers or cargo, dual-piston front calipers provide better initial braking force.
Important Note
Check clearance between brake discs and wheel spokes—oversized components may require upgrading to 17-inch wheels, which increases cost but improves handling.
Master Cylinder and Brake Booster Adjustments
The original brake master cylinder is calibrated for the weight and brake proportioning of the gasoline Logan. An electric conversion requires a larger bore master cylinder (e.g., 23.8 mm vs. the original 22 mm) to increase hydraulic pressure and compensate for the added weight.
The brake booster (vacuum assist) also needs modification: gasoline engines use intake manifold vacuum to power the booster, but electric vehicles lack this. Solutions include:
Electric Vacuum Pump
A compact 12V pump (e.g., from Bosch or Pierburg) maintains vacuum, ensuring the booster works as designed.
Hydraulic Brake Assist System
Uses power steering fluid pressure (from an electric pump) to assist braking, ideal for high-power conversions.
Ensure compatibility between the master cylinder and booster—mismatched components can result in spongy brakes or uneven braking.
Integrating Regenerative Braking
Regenerative braking slows the vehicle by using the motor to charge the battery, reducing reliance on mechanical brakes. For seamless integration:
Brake Pedal Sensor
Install a potentiometer or pressure sensor on the brake pedal to modulate regenerative braking intensity. Light pedal pressure triggers regenerative braking; heavier pressure engages mechanical brakes.
ABS Compatibility
Logan's anti-lock braking system must communicate with the electric vehicle controller to prevent wheel lock-up during combined braking. Use an ABS simulator or reprogram the existing module to handle regenerative braking inputs.
Brake Force Distribution Adjustment
Electric vehicles transfer weight differently during deceleration (batteries add rear weight). Adjust the brake proportioning valve to allocate 50-55% of braking force to the front wheels (less than the 60-70% for gasoline vehicles) to prevent rear wheel lock-up.
Brake Fluid and Maintenance
Electric vehicle brakes are used less frequently but face unique challenges:
Use DOT 4 or DOT 5.1 brake fluid (higher boiling point than DOT 3) to resist vapor lock during occasional heavy braking.
Change brake fluid every 2 years (sooner in humid climates) to prevent moisture buildup, which can cause corrosion in infrequently used brake lines.
Apply high-temperature grease on guide pins to prevent seizing, a common issue with brakes that sit idle for long periods.
Cost and Procurement Options
Upgrading the braking system will add $500 to $1,500 to your conversion budget, depending on components:
Testing and Safety Checks
After installation, perform these critical tests:
Follow the disc manufacturer's guidelines (e.g., 10-15 light brakes from 80 km/h to 30 km/h) to properly seat the pads and discs for even wear.
Use a decelerometer to measure braking force at each wheel; adjust the proportioning valve until front and rear wheels approach lock-up simultaneously under heavy braking.
Drive at 60 km/h, apply light brake pressure, and verify that regenerative braking engages smoothly before mechanical brakes activate. Check for jerking or delayed response.
Summary
Choosing a braking system for your Dacia Logan II electric conversion requires balancing weight, regenerative braking integration, and cost. Upgrading to four-wheel disc brakes, adjusting the master cylinder, and adding an electric vacuum pump ensure safe, consistent braking force. Combining these mechanical upgrades with a well-tuned regenerative braking system creates an efficient, reliable braking setup that aligns with the Logan's practical nature.
Remember: Brakes are the bottom line of safety—no compromises allowed. Invest in quality components and conduct rigorous testing—your converted electric vehicle's performance depends on it. With the right system, every brake application, whether navigating city traffic or cruising on highways, will be filled with confidence.
Need Help Choosing the Right Braking System?
Our experts can help you select the perfect braking components for your Dacia Logan II electric conversion. Get personalized advice on brake upgrades, regenerative integration, and safety testing.
Get Free Braking System Consultation
