Testing by Scott Tsuneishi and Tein Suspension
Spend enough time in the realm of performance import modification, and you'll come to a sobering reality: many of the parts marketed by your favorite manufacturers are exactly the same as those put out by their competitors. This is especially true of parts manufactured overseas, where your favorite wheels, exhausts, camshafts, and the like were born from the same foundries and machine shops as alternatives their ads have convinced you to despise.
Suspension companies are possibly the biggest rumored offenders of this, with many of today's low/mid-level coilover kits hailing from (the same?) overseas factories. This month we test two very similar mono-tube coilovers of competing makes to put one pertinent claim to rest.
The Claim: All popular adjustable coilovers are the same; cheap ones are just as good as any.
Our testing this month involves back-to-back-to-back testing of three different dampers for the '02 Subaru WRX: the stock unit and two of competing manufacture that are all but visibly indistinguishable if not for exterior design elements unique to their brands. The first is a mid-priced mainstay of import tuning: Tein's Mono Flex. The other, Brand X, is a substantially under-priced alternative-for all intents and purposes a knock-off, but one that the users of swear by its "same-as" performance.
This month's testing also involves a dyno, but not the kind you're used to seeing on these pages: Tein's NMB shock dyno. Now, before you get all, "They're testing a Tein damper at Tein headquarters, WTF?" know that Tein have invested in a shock dyno so they can better perform product testing and development, and to let third parties like us use it from time to time. Justice is blind, they say, and so are shock dynos.
Testing a damper (only called a "shock" if it doesn't play a role in steering a vehicle; "strut" if it does) is very straightforward. With the damper's base secured, the dyno compresses and extends the damper's piston at a range of velocities, measuring the maximum amount of force returned by the damper in response. How the damper reacts at lower piston velocities is indicative of its performance in instances of braking or acceleration squat, or body roll by a vehicle, while high-velocity piston travel mimics the force applied to a damper as it absorbs shock from imperfections in the driving surface.
Test 1: Stock
Testing of the stock WRX damper was done solely as a baseline, to show the nature of our STI's original equipment. Contrary to popular belief, stock equipment is usually of extremely high quality; it's just not always the most effective to use when combined with upgraded components or during enhanced driving. Note the damper's consistent, linear response to increased piston velocity after about 0.10 m/s-indicative of a quality product.
Test 2: Brand X
Our Brand X damper offers 29 levels of simultaneous compression and rebound adjustability. Rather than test each individual level, we tested at four increments, from firmest to softest: 0 clicks, 8 clicks, 16 clicks, and 29 clicks. The top part of our graph shows rebound adjustability, and while Brand X provided a wide range of adjustability at fairly evenly spaced levels, the results become inconsistent after about 0.15 m/s velocity, at which point the amount of rebound damping returned decreases as velocity increases at the hardest setting, but increases as velocity increases at the softer settings. Additionally, reading the data for the compression portion of the graph shows that damping of the "8-click" test (a firmer setting) becomes softer with increased velocity-even softer than the supposed full-soft "29-click" setting.
Test 3: Tein Mono Flex
Like the Brand X damper, our Tein Mono Flex unit offers simultaneous compression and rebound adjustability, only at 16 levels in total. We tested it at three even increments from firmest to softest: 16 clicks, 8 clicks, and 0 clicks. The rebound portion of the graph shows that while the three groups aren't as evenly spaced as our Brand X test, each is completely consistent and linear at velocities past the initial ramp-up of 0.09 m/s. Additionally, compression results are equally consistent.
It's important to note that while the Tein damper doesn't provide damping forces as extreme or far-reaching as the Brand X coilover, that's exactly what Tein were going for when they designed it. "Damping force is decided by spring rate, engine/drivetrain layout, and road/track testing," says Phil Chase, of Tein. "Our priority when developing coilovers is performance, comfort, noise, and damping force adjustment, in that order. The Mono Flex damper tested here is part of our off-the-shelf WRX STI coilover kit that's matched specifically to its 10kg/mm springs." Phil also points out that the small variability of adjustment offered by the Mono Flex compared to the Brand X is also a product of precision construction. "Fine-tuning a damper for a different track or surface conditions should really only occur in small intervals, if the same spring is used," he explains. "If a change of spring rate by more or less than 2kg/mm is desired, we recommend a complete damper re-valve to match."