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Project Sonic Boom - Nearing Completion

Putting the finishing touches on Project Sonic Boom.

Peter Tarach
Mar 13, 2014

Deadlines suck, but they make the world go 'round. Too bad the cutoff date for this project was ridiculous and we still had way too much to do. With empty Red Bull cans piling up, it was time to kick it into overdrive and get this Chevy Sonic RS done.

First up, the BC Racing Suspension. As you can imagine, proper coilover kits aren't exactly plentiful for this new platform, but coincidentally, BC Racing was putting the finishing touches on its BR Type Sonic kit when we got in touch with the company. Thank goodness because otherwise we would've been forced to run just lowering springs, and that wouldn't work well with our custom wheel and tire setup on this car.

Project sonic boom BC racing type BR coilover 02 Photo 2/18   |  
BC Racing Type BR coilovers for the Sonic not only allow ride height adjustment but also reduce body roll and improve ride quality.

Installation is pretty straightforward; BC Racing provides new metal sway bar end links (stock are plastic) for the front, but you'll need to reuse the stock top mounts on the coilovers or do as we did and just order new ones from Gandrud GM to avoid having to disassemble the OEM units.

Project sonic boom stock top hats 03 Photo 3/18   |  
Purchasing stock top hats and mounts will significantly speed up the coilover install, as you won’t have to remove the pieces off of the stock struts.

The rear solid beam suspension setup sees the shock and spring mount separately and also requires the use of the stock top mount. Swapping it over is quick and easy since there's no spring to deal with.

BC Racing coilovers allow for 30 levels of adjustment with actual easy-to-reach adjustment dials on both the front and rear. A clever piston-shaft-mounted dial adjusts the rear, while up front, extension knobs screw onto the top of the coilover. Without these extensions, adjustment would mean having to remove the cowling every time-and that's not something anyone would want to do.

Project sonic boom front extended knobs 06 Photo 4/18   |   Project Sonic Boom - Nearing Completion
Project sonic boom front extended knobs 07 Photo 5/18   |  
Up front, extended knobs make for easy dampening adjustment.

Despite the not-so-common suspension geometry, installation is still very straightforward. It helps that the BC coilovers have all the provisions and brackets for the stock brake and ABS lines to slide into. They're also much less bulky than the OEM suspension, which allows for more room to run larger wheels and tires.

Ride height adjustment is done through the shock body, so there's no need to mess with the springs. All these minor details add up and make the BC Racing coilovers a great addition to any Sonic.

Project sonic boom rear springs 04 Photo 6/18   |   Project Sonic Boom - Nearing Completion
Project sonic boom front strut 05 Photo 7/18   |  
In the rear, height adjustment is done on the spring itself, whereas dampening is conveniently located at the top of the strut.

On the street, body roll is all but gone-which was a big issue with the stock setup-and ride quality is vastly improved. These coilovers feel better over bumps than stock, but that's because we didn't hammer the car to the ground and actually left ample amounts of suspension travel.

As with any car, such as the Sonic, its brake system was never designed to see track use and therefore begged for an upgrade. That's when we turned to Brembo, and with its partner, Race Technologies, a GT big brake kit was spec'd out with 4-piston calipers and large, 328mm, two-piece rotors.

Brembo makes sure all of its kits have been designed to work with the stock master cylinder, providing balanced braking with a more solid-feeling brake pedal. Say goodbye to that stock mushy-feeling pedal and say hello to serious braking power.

The difference in stopping performance is staggering. Where the stock brakes would have a hard time keeping up with the 235-wide Toyo tires, the Brembo brakes instantly bite, bringing the Sonic to a grinding halt with repeated performance every time.

Project sonic boom brembo gran turismo brake upgrade 10 Photo 8/18   |   Project Sonic Boom - Nearing Completion
Project sonic boom brembo gran turismo brake upgrade 11 Photo 9/18   |  
Brembo’s Gran Turismo brake upgrade is a significant improvement over stock, and we’ll admit, it also looks a smidge better than stock—OK, a lot!

This brake upgrade is by far one of the best mods done to the car so far. With more power on tap and increased grip, the stock brakes weren't confidence inspiring at all. The Brembos change all that, and even though they aren't cheap, it's a mod that is worth its weight in gold.

Not that they need it, but our friends at Cyrious Garageworks built us some ducting that pushes air to the brakes through the bumper-mounted APR ducts. We didn't want to have those ducts nonfunctional, so this way they actually do something.

Project sonic boom custom ducting 12 Photo 10/18   |  
Making those APR ducts functional with some custom ducting to the brakes.

Jumping inside, initial plans were to swap the stock RS steering wheel out with an aftermarket one, but sourcing a hub proved a bit difficult-not to mention the stock wheel is actually really good and, to be honest, doesn't need to be replaced. Plus, changing it out means you lose cruise, volume, and voice command controls. A more suitable replacement is the Camaro ZL1 steering wheel that fits without any modifications. It even reuses the stock Sonic airbag. It's pretty much the same wheel as the RS, but it's covered in suede for a more race-oriented look and feel. We didn't think there'd be any downside to this upgrade until we tried to use the cruise control and it didn't activate since the buttons are just slightly different. It's probably just a few wires that need to be repined, and we're hoping to get to that one day.

Project sonic boom chevy steering wheel comparison 08 Photo 11/18   |   Project Sonic Boom - Nearing Completion
Project sonic boom suede camaro ZL1 steering wheel 09 Photo 12/18   |  
Replacing the stock leather RS steering wheel with the suede Camaro ZL1 is a simple switch ’n’ swap.

While the steering wheel was being installed inside, some Plasti Dip magic was happening outside. The chrome trim of the Sonic didn't really fit the theme of this build, so anything shiny was coated with a thick layer of flat, black Plasti Dip, and the results are worth all the time and effort we put into masking everything.

Project sonic boom plasti dipping 13 Photo 13/18   |  
Say goodbye to chrome. Plasti Dip makes the job quick and easy with very good results.

We also had to do something with the stock antenna that protrudes awkwardly from the roof-it's not a pretty sight. Bad New Racing came to the rescue with its shark fin replacement that just slides on top of the stock-mounting piece and is a super-easy install. It also comes painted, saving a trip to the paint shop.

Project sonic boom chevy sonic factory antenna 18 Photo 14/18   |   Project Sonic Boom - Nearing Completion
Project sonic boom BNR shark fin antenna 17 Photo 15/18   |  
A simple yet very visually appealing mod is replacing the stock antenna with a BNR shark fin.

To finish things off, window tint was the missing element, and not just any tint would suffice. Only the best would do, especially because we wanted a layer of reflectivity to give it a striking look. 3M had just what we were looking for in its Black Chrome window film. Utilizing metalized technology gives it that reflective shine we were after, and the film rejects up to 72 percent of the heat coming through the windows and provides considerable glare relief. Really, though, it just looks plain ol' awesome-and that's why we chose it.

Tint application is just as important as the film. You pick the wrong place and the tint will peel or rip before you know it. That's why we went to an authorized 3M installer. Mike Circ of Touch of Tint installed the 3M Black Chrome like it was going onto his own car. He also had a proper cutting machine that cuts precise window templates, leaving no room for human error. Add in his jokes and great customer service, and there's no other place we'll be going for our future tint and film application needs.

Touch of Tint applied 3M’s Black Chrome window film with precise perfection. The result: just the right amount of reflectiveness and awesome-ness.

To call it close would be an understatement, but the Sonic was completed just in time for our test day at the track. We've come to close on this chapter, so you'll have to grab a future issue to see how it performed and whether it lived up to expectations.


BC Racing
Casselberry, FL
Race Technologies
Costa Mesa, CA 92626
(714) 438-1118
Gandrud Chevrolet
Cyrious Garageworks
Bad News Racing
Boynton Beach, FL 33424
Touch of Tint
By Peter Tarach
352 Articles



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