The Wrangler (sport/sahara, not rubicon) has a Cd of .48 (of 1 sq/ft of plate area) and the Element is in the around .40 or slightly lower. That's just part of the story, since the total frontal is multiplied by the Cd to get relative drag number. The jeep has more frontal area than an Element. So, way more total drag in lbs/force at a given speed.
Doesn't a Honda Element have a significantly smaller cross-section along with significantly smaller tires (less rolling resistance)? Cross section is a multiplier in the formula for aerodynamic drag, but at least it's not like velocity that gets squared.
Let's say, hypothetically, the Jeep has a 20 sq/ft frontal area. Multiply 20 x .48 (Cd) and you get the equivalent drag, in sq/ft, of flat plates moving through the air, or Cdo (coefficient of drag overall). So, 9.6 sq/ft in this example. If the Element has, hypothetically, 15 sq/ft of frontal area and a Cd of .40, you get 6 sq/ft of equivalent flat plate frontal area. Or a Cdo of 6.
I pretty sure you're agreeing with me.
Yeah a moving brick.
Mmmm, sort of. It's the weight at the moment arm of the tire diameter. 100lb tire take far more power to get going than little stock ones.
Depends on how fast you want to accelerate them. Jack your rear axle, put it in gear with big heavy tires on it. They'll spin up very quickly with little throttle. The only objective way to test weight alone is to use the very same tires with added weight. The effects of a larger diameter act against your drivetrain in the same way a longer lever arm works to generate more torque/force than a shorter one. Weight matters most when accelerating the tire, but even that is a low order effect as compared to other factors like diameter and rolling resistance created from wider tread, and especially more aggressive tread pattern. Then throw in that everyone wants to run lower tire pressures. Weight falls way down the list, especially at level ground constant speed cruise. But I'll give you it is there.
