Acura Integra
For the most part, this hasn’t been an engineering project, but this is the never-ending project that started it all for me. It wasn’t until tinkering with this thing for a few years that I realized I liked working with machines and wanted to pursue engineering.
I started with some simple modifications: lowering springs, wider forged aluminum wheels, and summer tires. This paired with a manual transmission and the vehicle's rigid chassis made it a very fun car to drive.
About a year into owning it the car was totaled in an accident with a truck. After this, I decided to salvage it and take the opportunity to rebuild it myself over the following summer. I opted to replace the whole front end with the better looking Japanese domestic market front end. While I was at that, I decided to do a bit of much-needed maintenance, as it had some issues that made it a pain to drive. This refresh involved replacing the motor mounts with hardened rubber versions, installing a lighter flywheel, and replacing the clutch, axles, and lower ball joints.
Replacing the front end proved to be the toughest aspect of the whole repair. The radiator support frame member had to be cut out and the Japanese version had to be welded in its place. This entailed a long process of positioning all of the exterior body parts, without the radiator support fixed in place, and making small adjustments until the radiator support was well-placed. Additionally, the headlights had to be completely re-wired with additional relays and fuses as the locations of the lights and the types of lights had changed. It was with this large project that, for the first time I got to experience how the parts of a machine fit and work together to fulfill their purpose.
I have since installed stiffer springs and dampers, extreme summer tires, camber-adjustable front upper control arms, more aggressive brake pads and rotors, a fixed bucket seat, and a quieter OEM Integra Type R exhaust.
I am always thinking of ways I can make it a more fun driver’s car without altering the car too much to the point where the essence of the original vehicle is lost. Some things I'd like to do in the future include replacing all of the suspension bushings, correcting the angles of the control arms, and replacing the transmission for one with shorter gear ratios and a limited-slip differential.
The car as it was when I originally bought it.
The car today.
The car after the accident.
Design of Experiments
For my Design Methodology class (ME 366J), we were tasked with performing a simple design of experiments (DOE) where we identify a system with a measurable response variable, vary two different control factors, and measure the response. We then had to perform a statistical regression analysis to determine if the control factors had any impact on the response variable and if the control factors had any interplay.
In my DOE, I varied the damping and tire pressure in my car to see the effect on ride quality, which was quantified by the vertical jerk experienced by an accelerometer attached to the passenger seat. The result: Softer tires and softer damping produced a softer ride or less vertical jerk, while stiffer tires and stiffer damping produced a more bumpy ride or more vertical jerk. While the results were exactly as expected, it was enlightening being able to gather data with an accelerometer and quantify the ride quality of a vehicle.
A brief video describing the experimental setup can be seen here or at the bottom of the section.
Data of vertical jerk over the length of the road and mean magnitude.
Data of vertical jerk over the length of the road and mean magnitude.
Data of vertical jerk over the length of the road and mean magnitude.
Data of vertical jerk over the length of the road and mean magnitude.
Interaction plot of the two control factors: damping and tire pressure.
Statistical regression analysis results. All P-values are less than 0.05, so with 95% confidence, the intercept, X1 (damping), X2 (tire pressure), and the interaction term X1*X2, are all statistically significant.