New Honda Insight has higher cD than Civic Hybrid

[winkosmosis]

According to Motor Trend, Insight's cD is 0.05 higher than the Civic Hybrid's.

http://www.motortrend.com/roadtests/...xperience.html

A lot of us raised our eyebrows when the Insight's mileage numbers were officially released as they're actually lower than the older-tech Civic Hybrid (Civic-40/45, Insight-40/43). The culprit? Well, sacrificing the three-stage i-VTEC mechanism on the altar of the Insight's squeaky-tight IMA budget probably hasn't helped. However, we're completely baffled by the car's drag coefficient, which somehow or another is slightly inferior to the Civic's.

^ They removed the 0.05 number from the online version of the article

How can that be? The Civic Hybrid is a sedan with a fairly steep rear window, and the Insight is an aero-optimized kammback.

Could it be those wheels alone??

[SVOboy]

Definitely could be the wheels. Maybe there's something else going on.

[winkosmosis]

Could be that the shape is optimized for interior room. It could still have lower drag if the frontal area is smaller.

[Blue07CivicEX]

WTB skirts on the back like the old insight.

[KJSatz]

Well sounds like my Civic sedan (LX, not hybrid) is pretty aerodynamic...but there are plenty of improvements made for the hybrid. I should get cracking.

[MetroMPG]

Since the Insight arguably has better shape optimization, the difference is in detail optimization between the two vehicles.

Wheels are one factor. But there could be other reasons like: enging cooling optimization, ground clearance (Civic looks to be lower, and definitely has a lower front air dam), undertray panels, just to name a few...

[Blue07CivicEX]

So, wait... what's the point of buying an insight again? What makes it better then a civic hybrid? Is it just the price? If that's the case screw both of them I'll keep my EX that I can get 40+ mpg for and it's fully loaded (for a civic). The insight should have been like the old one with the civic/accord hybrid (need an accord hybrid) for the other market share that need a larger more family type car. Keep the insight a super efficient commuter/around town car.

[Cd]

Let's also remember the LS 430, which matched the Insights drag coefficient of .25, yet had a super steep rear glass, and huge honking wheels.

[Cd]

The new Insights wheels are mostly flush when viewed from the sides ( no really bad protrusions or cavities.



Not sure about the production car though.

( Just curious about the angle of the underside just past the rear bumper - is the angle aerodynamically correct ? )

Another thing that puzzles me is how the Cd is so good on the Civic sedan, yet it has such a short trunk. From what I understand, if there is airflow seperation, you usually need a long trunk, or a high spoiler to reattach the turbulent airflow and straighten it back out.

[donee]

Hi Cd,

I really do not think that is the version of the LS430 with a Cd of .25. I have been up close to one of those, brand new, and it definately looks like it has been worked over aerodynamically. The car in the picture has many things different from the latest model of the LS430.

Take a look at this link to a LS460. This is what a new LS430 looks like:

http://en.wikipedia.org/wiki/File:Lexus_LS460_02.JPG

Note the Prius like treament of the rear glass and depression of the trunk lid, and generally faired in surfaces. Much different.