Project Type R: KW Variant 3 Track Test

October 08, 2009 | Project Cars | Project Type R | Andrew Wojteczko | Comments (0)

KW Variant 3 Highlights

• $1445 USD - best deal we could find online
• Separate low speed compression and rebound damping adjustability allows for tuning of pitch and roll rates as well as handling balance at corner entry and exit
• Excellent stability on the track and good ride quality around town
• Stainless steel shock body adds weight (compared to aluminum body shocks) but ensure a rust- and corrosion-free finish that prevents the coilover ride height adjusters from seizing.

Installation Highlights

• Pre-test preparation: removed, anti-siezed and reinstalled all suspension nuts and bolts; set KW ride height adjusters to the middle of the recommended range and installed new OEM top hats; oil and brake fluid checked.
• Approximately 1-hour with three experienced mechanics and hand tools. Allow for 3-4 hours for less experienced mechanics.
• Jack stands used on all four corners for safety

Track Test Highlights

• Sunny and warm weather conditions: 25°C | 77°F
• Shaved Toyo RA-1 205/50ZR15 tires used for their consistency and durability
• Front shocks set to 8/16 position for compression and rebound, rear shocks set to 16/16 (full stiff) position for compression and rebound on the rear
• Pro driver fastest lap time: OEM shocks/springs = 1:25.0, KW V3 = 1:24.0
• Novice driver fastest lap time: OEM shocks/springs = 1:36.1, KW V2 = 1:33.6

The Integra Type R is a special car in many ways, one of which is the precision and handling balance it comes with from the factory. The car is very capable and rewarding to drive in stock form, making it difficult to improve upon with aftermarket modifications, especially in the handling department. Consequently, it was necessary to perform a back-to-back evaluation under the same conditions to see if our planned suspension upgrade would deliver the performance improvements we hoped it would.

We also added another element to the test by including both a professional Touring Car driver and a relatively new lapping day participant with limited track driving experience. The goal was to see what gains (or losses) were to be found around a race track after replacing the factory shocks and springs with a high quality aftermarket coilover system, but to also see how the gains (or losses) vary for drivers with different experience and skill levels.

We chose the KW Variant 3 coilover suspension system for this comparison for several reasons. First off, it is priced within reach of most budget-conscious track day enthusiasts (we found our set from an online dealer for $1445 USD shipped).

Our past experiences with KW have also been positive, offering a great balance of body motion control while maintaining good ride quality for around town. The dampers are a true coilover setup allowing for a wide range of ride height adjustment and also offer independent low speed compression and rebound adjustment (low speed is a damper shaft speed typically less than 1"/second and typically occurs during transitions such as releasing throttle/applying brake [pitch] or when steering [roll]). Consequently the ability to adjust low speed damping is very important to handling balance during transitions and is a big plus in this price range. More on tuning the dampers later. Finally the bodies of the dampers are stainless steel, which adds a weight penalty compared to an aluminum-bodied coilover but ensures the adjusters will not seize up when exposed to road salt/winters and the bodies will not corrode.

To prepare for the test every suspension related bolt was removed, lubricated with anti-seize and reinstalled to make for a no hassle trackside swap. The ride height on the KW’s was set to the middle of the recommended range and a fresh set of OEM top hats were installed to complete the assembly. Finally, front compression and rebound were set to 8/16 clicks each and rear compression and rebound were set to 16/16 clicks (full stiff). The fluids were checked, brakes bled, and the Type R was ready to go to our testing grounds, Toronto Motorsports Park.

Our team arrived at the track to perfect conditions, sunny with a cool breeze. Track conditions were monitored over the course of the day and remained fairly consistent. We chose a used set of 205/50-15 Toyo RA-1 tires to perform the test. A used tire was important, as it would provide more consistent grip throughout the test. A new tire (especially that has not been heat cycled) will make peak grip within its first few laps then begin to drop off. A used tire that has already passed through this phase of its life will typically offer a period of consistent grip before the tread wears excessively and grip rapidly falls off at the end of its life.

Cold tire pressures were set and our pro Touring Car racer Driver A was sent out to establish the potential of the car with the stock suspension still in place. A fast lap of 1:25.0 was recorded on the Drift Box GPS data system. Our recreational track day driver Driver B was clocked at 1:36.1 as her baseline run.

After that the Type R was put up on stands and the stock suspension removed. With all the bolts lubricated the removal was a breeze and the KW’s were ready to go in. All the fasteners were torqued to spec (see figures 1.1 and 1.2 for the values) and the Type R was ready to go back out for another set of hot laps. Be sure that the suspension is at ride height before tightening any fasteners holding bushings that twist as the suspension travels. We used a floor jack at the outer end of the lower control arm while the car was on stands and then tightened up the bolts.

Figure 1.1 Front suspension torque values

See the difference?

Figure 1.2 Rear suspension torque values

Once again Driver A was first behind the wheel and following the same format as the baseline, achieved a fast lap of 1:24.0, 1 full second quicker than the baseline. Next up Driver B posted a 1:33.6, an exceptional 2.5 seconds faster than her baseline run.

Where did the time come from? The KW V3s increased spring rate and greater damping force made a huge improvement in the stability of the vehicle. In stock form the R would experience large pitch angles under hard braking, making the rear of the car start to dance. With the KWs installed, braking confidence was improved as the car was pitching less and consequently maintained better wheel alignment (less camber and toe change with less suspension travel). This also resulted in less time required for the car to transition from peak braking force to peak lateral force, allowing the driver to brake a little deeper and build maximum lateral acceleration more quickly. The KWs also seemed to better control the wheel movement over the rougher portions of the track, increasing grip in the process. Where the stock diff would get over-powered with gas pedal to the floor during some of the rougher corners and some inside wheel spin resulting, the KW’s improved high speed damping increased traction and minimized wheel spin in these turns, ultimately resulting in greater corner exit speeds.

The GG diagrams (showing a scatter plot of lateral G and longitudinal G or acceleration experienced during a lap) help illustrate the handling improvements found with the KW suspension upgrade. The GG diagram following the suspension upgrade shows the R was better able to follow the ideal traction ellipse, where peak G-force is maintained during the transition from braking to turning to accelerating. It is also possible to see that peak cornering force has increased. It can be seen that braking force decreased slightly which is most likely related to brake fade that gradually increased over the course of the test.

Our recreational lapping driver was very impressed with the lap time improvements she achieved. "The car inspired more confidence, it was quicker to change direction and I was able to apply gas earlier. I did have to be smoother with my steering to not upset the car though," said Driver B.

The drive home from the racetrack was also the perfect opportunity to evaluate the civility and daily drivability of the KW V3’s. The ride is slightly firmer than stock yet not harsh and the OE top hats keep things quiet. The car does not bounce uncomfortably over irregularities, indicating that KW got the high speed damping just right. It’s also reassuring to know the stainless bodies will stand up to whatever road conditions they may be exposed to.

In conclusion, the KW Variant 3 coilover setup is a great upgrade for the DC2 Acura Integra Type R for all driving conditions and all driver abilities. You can expect more stability and quicker transitions with improved grip over the bumps. The adjustability also makes it possible to fine tune for specific circuits and weather conditions. We were very pleased that the Type R magic was maintained. Trail brake and lift throttle induced rotation was still easily provoked yet very manageable, one of the characteristics we love best about the stock Type R. The Integra R is one of the best handling, most enjoyable FWD cars ever made and the KW V3 upgrade improves upon its legendary handling abilities in every environment we’ve tested them in. Kudos to KW!

GG Diagram 1. Stock suspension g-Force diagram for lateral and longitudinal acceleration.

GG Diagram 2. KW V3 suspension g-Forces for lateral and longitudinal acceleration. Notice increased peak lateral acceleration as well as increased lateral acceleration during transitions from brake to steer to gas. The slight reduction in braking Gs is most likely a culprit of brake fade that occurred later in the test.

October 08, 2009 | Project Cars | Project Type R | Andrew Wojteczko | Comments (0)