CleanSpeed 4

CleanSpeed 4 (CS4) is AERO’s eigth generation vehicle, and fourth generation electric vehicle. Going into the design of CleanSpeed 4, AERO had two primary goals. The first goal was to improve on the performance of CleanSpeed 3 by decreasing weight and increasing power output. This will be done by using lighter, more power-dense Lithium-Ion batteries instead of Lithium Iron Phosphate batteries. To handle the extra power, CleanSpeed 4 will use a new motor and motor controller. The second goal was to implement a robust data acquisition and telemetry system, which should improve the design of future cars, as well as increasing performance at competition. This data acquisition project will be conducted as a Senior Capstone Project for the senior members of the team.

Early CAD model of CleanSpeed 4.0


Battery ChemistryLithium ion
MotorEmrax 228 MV
Battery Capacity5.76 kWh
Battery Voltage288 V
Peak Power63 kW (85 HP)
Wheelbase72 in
Track Width54 (front)
52 (rear)
Height46 in
Weight600 lbs (estimate)

Battery Pack

CleanSpeed 4’s battery pack is the largest improvement over CleanSpeed 3. It uses Samsung 18650 cylindrical cells for a much higher power-to-weight ratio. These cells are assembled into 8-cell parallel modules by Energus for rules compliance and ease of assembly. The car will have two sidepod-style battery packs on either side of it, next to the driver, each with 40 battery modules in it, for a total of 80 modules. The total weight of the pack (with both side-pods) is 60kg (130lbs), which is less than half of CleanSpeed 3’s pack. Even with this 50% weight reduction, the new packs have only 10% less capacity and can deliver twice the power with higher efficiency.

Exploded view of CleanSpeed 4’s battery pack


CleanSpeed 4’s powertrain has been redesigned to handle the full power of the new battery packs. It uses an Emrax 228 medium-voltage, combination-cooled PMAC motor controlled by a Rinehart PM100DX 3-phase motor controller. These components have a minimum efficiency of around 85% at full power draw, which is higher than CleanSpeed 3. This means the motor is less prone to overheating, even with a higher power output. This configuration also allows for regenerative braking, which will help maximize performance in the endurance event.


CleanSpeed 3’s suspension was its biggest improvement over any vehicle AERO had made in the past. Because of this, CleanSpeed 4 will use many of the same components with extensive geometry updates. While the uprights from CS3 will be kept, geometry changes including track widths, roll centers, caster angles, camber curves, and motion ratios, as well as component redesigns to bellcranks and control arms will be made.


Due to the side-pod battery packs, CleanSpeed 4’s frame has been made narrower and lighter than CleanSpeed 3. The entire tube structure is made of 4130 chrome-molly steel which is fully TIG-welded together. Stylistically, it includes features from each of the previous CleanSpeed frames. Its overall shape and more enclosed cockpit are reminiscent of CleanSpeed 1, its front end is similar to CleanSpeed 3, and its narrower body and main roll hoop shape are similar to CleanSpeed 2.

Evolution of CleanSpeed frames, from CleanSpeed 1 on the left to CleanSpeed 4 on the right.

Data Acquisition

Coming Soon