The Sonic cousin: Buick Encore / Chevrolet Trax
In a quest like this, the first thing to do is figure out which parts can be borrowed from other vehicles that have the feature you want. It turns out the Chevrolet Sonic, Chevrolet Trax, and Buick Encore all share something in common: the chassis. Known as the GM “Gamma II” chassis, it started in the US in 2010 as the Chevrolet Spark. In 2011 the Chevrolet Aveo was introduced. In 2012, the Aveo was renamed as Sonic, and in 2013 the Buick Encore and Chevrolet Trax were introduced with optional AWD. The Sonic, Encore and Trax use the 1.4L turbo MPFI engine (RPO: LUJ/LUV).
Borrowing the AWD System
For our project, we obtained a 2015 Chevrolet Sonic RS and an AWD Chevrolet Trax. The Chevrolet Trax has a transverse mounted 1.4L turbo engine, mated to a 6 speed automatic transmission. A transfer case attached to the transmission sends power to a rear differential via a propeller shaft. An ECU (Rear Differential Clutch Control Module) controls the amout of torque transferred from the propeller shaft to the rear differential.
Not as easy as it Sounds
Given these vehicles are all “Gamma II” chassis vehicles, we just need to unbolt the AWD system from the Trax and install it in the Sonic, right? Not quite. To name just a few challenges: We had to cut the spare tire well out of the Sonic to make room for the rear differential. We had to swap the rear suspension from the Trax in its entirety because the Sonic suspension doesn't have a provision for the propeller shaft. The propeller shaft will need to be shortened.
Maybe a Rally Spec car instead of a Hot Hatch
One other issue we've run into so far, is that the Trax suspension sits higher than the Sonic suspension. The overall ride height will be about 1.5” higher than the original suspension. Maybe we should make this into a Rally spec car instead of a Hot Hatch!