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A Deep Dive Into the CR-Z

Many people have been asking us about our new Honda CR-Z.  In light of the recent spike in fuel costs, and the events in Japan, I feel we were fortunate to purchase our car when we did.  What follows are my thoughts on the mechanicals of the car and a driving perspective.  

Let us begin by looking at the chassis itself.  With an overall length of 160.6 inches, it’s one of the smallest cars we’ve owned.  For comparison, our RSX is ‘huge’ at 172.4 inches long.  It also sports a shorter wheelbase at 95.9 inches (the RSX is 101.2) but is slightly wider than the Acura at 68.5 inches.  These dimensions give the car a hunkered down look that enhance it’s sporty profile.  Under the car, the chassis has a nearly flat floor and fairings and covers fill in the rest to help smooth airflow and improve aerodynamic efficiency.

On paper, some of the stats show the car’s humble origins, including the torsion beam rear axle, McPherson strut front suspension, and modest 1.5 liter iVTEC engine.  However, when you dig deeper, you’ll see interesting little tidbits.  For example, the front suspension uses forged aluminum lower control arms to reduce unsprung weight.  This helps keep the tires in better contact with the road surface and give better feedback to the driver.

The rear suspension was dictated more by the desire to package the IMA batteries and Powertrain Control Unit low over the rear axle.  However, steps were taken here to increase the rear track, improve stability and keeping this weight over the rear wheels, helps balance the chassis somewhat.

On the road, the suspension is a mixed bag.  For a sporty car, it’s a little on the soft side and I feel the shock absorbers could use a little more rebound dampening.  These somewhat soft shocks and springs allow for a little body roll, but it’s not excessive till you’re pushing it hard.  The trade off is that the ride is significantly improved, especially for a car with such a short wheelbase.  It exhibits none of the “choppiness” that plagues our RSX and the CR-Z is riding on a 5”+ shorter wheelbase. 

The steering feel, while very light, is also very direct with a go-cart like steering ratio.  I was so impressed that I did a little extra research and was surprised to find that it’s actually faster (12.8:1) than our old S2000 (14.9:1).  For those less familiar with this term, a car’s steering ratio expresses how much you have to turn the wheel (in degrees) to achieve the desired steering effect.  A fast (smaller) ratio means that small movements of the steering wheel affect the tires to a greater degree.  In practice, it goes exactly where you point it with a reassuring immediacy. 

The six speed manual transmission is a joy to use, shift throws are short and shift effort is very light.  The shifter lacks the ‘rifle bolt’ feel of the S2000 transmission, but also loses a lot of the notchiness associated with that.  In the end, there is very little play in the gear lever and it has a solid feel to it.  In day to day traffic, we really appreciate the lightweight clutch and it’s linear travel.  The Hill Start Assist is just an added bonus.  In fact, as a lifetime manual transmission driver, I've become accustomed to quickly moving from brake to gas on a hill (to keep from rolling backwards). The Hill Start Assist sometimes makes it harder because its still holding the brakes and I'm trying to give it gas.  I've actually stalled the car because of this but now I pause a second before releasing the clutch.  

There seems to be a lot of confusion regarding the Honda Integrated Motor Assist hybrid system and how it works.  Without going into all the details, lets just say that except for the auto-stop feature, you’d never know you were driving a hybrid.  Because the IMA motor is attached to the flywheel, the car never runs ‘all electric’ but the system is there to add extra power if needed. In day to day usage, you’d never know that the engine was a 1.5 liter cause it feels much larger, closer a 2.0 liter.  

Interestingly, assist that is provided from the Hybrid IMA system is most noticeable in the improved torque output.  Although only rated for 128 lb-ft from 1000 to 1750 RPM, it’s still providing ~90% of that torque up to 5000 RPM.  This makes for an extremely comfortable driving experience with the car operating smoothly in 6th gear at speeds as low as 25-30 mph.  Whenever you get off the gas, or step on the brake, the motor changes to a generator to recapture the kinetic energy that is otherwise lost to brake dust and heat. 

 This leads into another misconception regarding battery usage.  I have heard people say, "you don't have any power once the battery runs out".  To this I reply, "yes, you certainly have less power, but remember that the battery recharges almost as quickly as it discharges"  This is not like your cell phone where you charge it for hours but if battery dies, you're out of luck.  Regenerating power is all done behind the scenes.  This quickly becomes routine, the batteries recharge everytime you take your foot off the gas and coast, or when you apply the brakes.  It only takes one steady application of the brakes to recharge the batteries and you're ready for the next green light.  It's a constant ebb and flow of energy in and out of the system. 

The three driving modes are where this car starts to define itself.  Like all our recent cars, the CR-Z uses a drive-by-wire (DBW) and this plays a critical role in this car.  "Economy" mode calls up a higher percentage of electric assist and really dampens the throttle response of the gas engine.   "Normal" mode is a blend of qualities, and the default setting when you start the car.  With the car set to Econ or Normal, there is a lot of gentle coaching to help you get better fuel economy.  There is an upshift light and the entire tachometer changes it's backlighting from green (good) to blue (not as good) to give you realtime feedback.  When you change the mode to "sport" the computer changes the DBW throttle map, calling up more of the gas engine and all that electric torque as soon as possible.  In sport, tachometer glows red, the car takes on a totally different personality and even has reprogrammed steering assist to give higher weighting and more feel.

Many of the reviews I've read complain about the lack of urgency in Econ Mode and looking at the throttle maps above, you can see why.  However, it's important to understand that if you floor the accelerator, you will get the same throttle opening as you would if you were in Sport Mode.  I think it's obvious which mode is the most fun to drive, and if you drive Sport Mode carefully, you can acheive the same results as Econ, it's just easier to do in Econ.  Driving the car in our normal commute, we can use the driver aids and have quickly learned what the car 'wants'.  We're pretty easily averaging 40 miles per gallon and interestingly, our average speed over a tankful is rarely more than 30 mph.  I would take this to mean that our driving is probably closer to the EPA City definition and not the Highway. 

As a sporty car, I'd have to say it's best defined as 'quick' verses 'fast' and I've rarely found myself at a huge power disadvangage in normal driving.  On paper, the 8-9 second 0-60 times don't tell the whole story.  In the 6 speed manual version, 2nd gear tops out at 55-57 mph so you need to shift to 3rd to hit 60.  To reinforce this, MotorTrend recently came up with a 0-50 time of 6 seconds so this likely accounts for the difference between what owners feel and what most magazine reviews seem to focus on.  Could the car use more power?  Of course it could!  There are few cars out there that you couldn't make that statemement about.  There is a lot of talk about future model with more power with no sacrifice in fuel economy. 

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