Recently rumors surfaced surrounding the Volt's ability to seamlessly transition between it's different power modes, now additional rumors are flying regarding GM's reluctance to release any aerodynamic figures for the Volt. 

According to GM, the aerodynamic numbers of the Volt would best most competitors but posting them is not the right thing to do now.

Chief designer Bob Boniface said, "People may think we are skirting the aero issue by not quoting our tunnel figures.  We are not.  The fact of the matter is many of our competition quote grossly exaggerated aero figures that are not repeatable when we test their vehicles in our tunnel."

One thing GM has maintained in regards to aerodynamics is that they have no interest in engaging in an aerodynamic war with other companies.  The Tesla Model S is expected to have a cd of .26-.27 and GM will not announce if they can beat that number.  They do not want to engage in a race to be the best much like the horsepower race that dominated the American companies in the muscle car era.

As Boniface said, "If I quote an actual GM derived tunnel figure, it may not look impressive to you when, in fact it is superior to most if not all of our competition.  It is very much like the horsepower race back in the 60s.  The Volt aero performance is second only to the EV1 in GM history."

There you have it.  GM has no interest in releasing aero numbers for the Volt other than stating that it's not quite to EV1 levels, but better than any other vehicle they have ever made.

Source:  Wards Auto (Login required)