What about the hardware?
While the improvements in design and safety are critical to the success of the 2007 CR-V, what good would it be if there weren't signficant upgrades to the chassis and running gear?
Under the hood, Honda's upgraded the 2.4L DOHC i-VTEC K-series engine by applying basically the same changes that were made to last year's Accord. These enhancements essentially amount to a slight bump in compression (from 9.6:1 to 9.7:1), optimized valve timing, and improved flow through the intake and exhaust systems. The result is 166hp (+10hp) at 5800 rpm and 161 lb-ft (+1 lb-ft) at 4200 rpm. The numbers don't tell the full tale as the torque curve has been widened considerably, with the K24 now holding on to nearly peak torque levels to beyond 5500rpms. For comparison, the torque of the previous iteration of the K24 peaked at 3800rpms and began rolling off fairly quickly beyond 4500 rpms. Unfortunately, Honda is no longer offering a manual transmission on any of the '07 CR-V models, so the only available transmission is a smooth shifting 5-speed automatic. The 5AT first appeared in the 2005 refresh of the CR-V, and for 2007 it arrives with slightly shorter gearing in the first 4 gears and a 1.4% shorter final drive, resulting in roughly 6-8% shorter gearing in the first four gears. Also improved is the CR-V's venerable RealTime All-Wheel drive system, which was updated in 2005 to incorporate a one-way ball cam to improve responsiveness. Honda now claims to have increased torque capacity of the clutches by 20%. Furthermore, the system has been designed to operate with VSA Cooperative Control - this system is said to provide additional rear torque biasing during both low-slip and high-slip conditions. Interestingly "mid-range torque characteristics" remain unchanged.
To improve ride, handling, and NVH characteristics, the 2007 CR-V has benefitted from a number of chassis updates. Honda's primary goal was to provide a "solid and tight" driving feel which would provide a more sedan-like experience. To achieve this dynamic target it was determined that 3 primary areas had to be addressed: 1) The center of gravity had to be lowered 2) A more rigid body structure and 3) Driving performance.
With a height reduction of a scant 0.1", clearly additional measures were necessary to meet Honda's first goal. The primary steps taken to push the center of gravity closer to terra firma included widening the front and rear track (+1.2" and +0.8", respectively), relocating the spare from the tailgate to a spot beneath the cargo floor, and lowering the entire drivetrain by roughly 3.9mm. All of these combined to effectively lower the center of gravity from 670mm to 630mm, providing a huge improvement in the feeling of dynamic stability. From a safety standpoint, it also serves to improve the static stability factor and improves the CR-V's NHTSA Roll Over Inclination Angle rating by 3 degrees.
|Technical Note: Honda's Suspension Designs|
Honda is employing a few tricks these days with their MacPherson strut suspension tuning that seem minor, but they go a long way towards helping their vehicles perform and feel better from behind the wheel. One of these tricks is the use of inversely wound springs. Traditionally, suspension coil springs are all wound in the same direction. Honda's new springs are wound in opposite directions (clockwise for one side of the vehicle, counter-clockwise on the other side). Since the springs on MacPherson strut equipped cars exert a torsional force during compression/decompression, they can create a bump steer condition, which causes the vehicle to feel unstable under suspension compression or rebound. By using inversely wound springs, the springs exert opposing torsional forces that counteract each other, thus reducing bump steer.
Another trick Honda is using relates to the front suspension's caster angle. By using increased positive caster angles, straight-line stability is improved and steering effort and feel are slightly increased. Increased caster also helps generate negative camber during turns which aids grip - an important consideration on Macpherson strut suspensions which lack the camber gain traditionally available with double wishbone setups. It also works in concert with the springs to reduce bump steer and keep the wheels traveling straight. Related to this is the trail angle, which is where the steering point is placed in relation to the center of the wheel. In optimizing both the caster and trail, Honda is improving the steering feel and tracking of their cars. This technical jargon translates into a vehicle that's easier and more fun to drive, whether you know why or not.
Strong Body, Sound Mind
A stiff body structure is key to improving the overall driving experience, and by increasing the application of high-tensile strength steels to 58% (up from 34%), Honda managed to create a body that's now 84% stiffer in bending rigidity and roughly 3% stiffer in terms of torsional rigidity. All this added stiffness helps reduce creaks and rattles in addition to improving the driving stability.
To keep wind noise at a minimum AND improve driving stability, Honda also paid close attention to the aero details of the 2007 CR-V, utilizing underfloor covers, strakes, and "ultra tight" panel gaps to reduce the drag coefficient by 10%, for a best in class figure. This has the added benefit of improving fuel economy, which has increased by 1mpg vs. last year's model - this is despite the 2007 CR-V's increased frontal area, shorter gear ratios, and more powerful engine. With regards to improved stability, the aerodynamics were tuned to minimize front and rear lift. In fact, Honda claims an overall improvement of 67% in this regard, and though the driving impressions are to be found on the next page, this is certainly something that is evident on the freeway.
Suspension: Sporty and Secure
While the CR-V has always been nimble for an SUV, it did have a bit of a top-heavy feel to it. So it's no surprise that Honda aimed to lower the center of gravity. With that goal behind them, the CR-V team sought to further enhance the handling characteristics and push the CR-V even closer to its "sedan-like" bogey. The basic front MacPherson strut and rear multi-link suspension configuration carries over, but there have been numerous changes to the componentry and geometry. Up front, as part of the overall effort to improve stability, Honda specified high friction damper bearings (increased from 3.1lb-ft to 10.4 lb-ft), increased the anti-dive geometry (from 2.75 to 5.92 degrees), and (just like the 2006 Civic) they fitted symmetrically wound springs. To improve responsiveness as well as stability, Honda again employed some of the same tricks they used with the '06 Civic and increased the caster angle (from 1.75 to 3.04 degrees) and increased the trail (from 0.44 to 0.79 in.). Additionally, all '07 CR-Vs are fitted with larger P225/65R17 wheels. Finally, a larger lower arm compliance bushing and lengthened suspension rebound stroke help balance the comfort/performance equation.
At the rear of the vehicle, the CR-V's multilink suspension has been fitted with a 6% stiffer sway bar, providing improved turn in response and flatter cornering. Anti-lift geometry has increased from 14.5 to 16.9 degrees, while a new integrated hub and bearing (with a 57% wider span between bearings) has improved the hub rigidity by 9%. A light weight aluminum knuckle, a larger compliance bushing, and a "larger mechanical compliance angle" are all intended to improve ride comfort.