Last month, we began a quest to find out how much power potential Volvo's S40 may have. Teaming up with International Product Development (IPD), we re-flashed the S40's ECU and upgraded the exhaust. This time, we'll work on the chassis.
The PartsWe're opting for Eibach's Pro-Kit lowering springs. The progressively wound coils increase resistance upon compression and drop the S40 1.2 inches. The Pro-Kit's dual-rate design also allows for both soft and firm characteristics, depending on driving conditions.
Next for Project S40 are Bilstein dampers. The front struts feature an inverted design with internal bump stops and pistons that are nearly twice the diameter of the stock setup. The larger, more rigid piston can withstand greater lateral loads when cornering. The Bilsteins also use a digressive valving system that absorbs initial shock loads prior to applying full damping.
Lastly, IPD supplied its solid core, 22mm rear anti-roll bar. The chrome-moly piece features forged ends and includes all necessary bushings, brackets and hardware. The bar is not adjustable, but at 2mm larger than stock, it is 42-percent stiffer.
Removing the front dampers is simple. Take out the three upper bolts, the lower retaining bolt, the brake line and the ABS signal wire. The factory upper mounting plate and dust boot must be reused, but the stock bump stop will no longer fit. The thick coat of paint on the Bilsteins means it will require extra effort get the struts to slide fully into the lower hous
Since the upper-rear shock bolts are accessible from beneath the vehicle, the entire removal and installation process may be done from underneath. The rear shocks reuse the OEM hardware, upper mounting plate and bump stops, which may require lubricant to slide over the larger shafts. There's no need to trim the bump stops since the lower-rear control arms feature their own bump stops that do most of the work.
Remove the brackets and loosen the corresponding ball joints to remove the rear anti-roll bar. Position the new anti-roll bar on the ball joints before attaching the brackets to the rear crossmember. It's best to perform this step with the rear dampers intact. Removing the dampers and anti-roll bar at once disrupts the suspension geometry and makes assembly more difficult.
Wheels and TiresHeico Sport IV supplied the 18x8-inch Evolution V wheels, which are wrapped in Vredestein Ultrac, tires sized at 225/45-18. The tires feature the company's Ultimate Handling Construction, which provides additional sidewall stiffness for better handling. The one-piece rims are constructed of lightweight alloy and feature a 45mm offset, which is 7.5mm less than the stock alloys.
BodyThe guys at IPD installed a Heico front grille and spoiler, along with a rear wing from MS Designs. The mesh grille is housed inside a chrome frame featuring the company's logo and snaps right in. Both the front spoiler and rear wing, which we had painted by Wetworks Garage of Costa Mesa, CA., are constructed of fiberglass. The spoiler isn't a cover-up piece but instead replaces the original. The rear wing is magnetic, but applying an adhesive is recommended because it won't take much to yank it off.
PerformanceThe suspension add-ons, like the engine upgrades, produced only marginally better results. Skidpad testing yielded a .03g improvement, bringing the Volvo's stick up to .84g while slalom numbers bumped slightly from 66.3 to 67.6 mph-not an earth-shattering improvement, but an improvement nonetheless.