[baldlobo]

Originally Posted by aerohead

*On most modern vehicles there won't be any flow separation until somewhere in the rear so typically it's not an issue for front lift.

i agree

*The JEEP may have separation in the cowl area as well on top of the roof,downstream of the A-pillars.Both these locations would produce lift.

past the A-pillar, yes; the cowl area, probably has a dead spot bigger then a normal car's due to the windshields steep incline but it's not before the front axle(weight distribution is 60/40 or so;2500lbs/1500lbs). smaller pockets of instability probably are around the hood hold downs.

*The undercarriage of the JEEP would register one of the highest drags for production vehicles.Air attacking from ahead would encounter a torture-chamber of assorted mechanical obstructions,creating much turbulence.The turbulence makes it impossible for kinetic energy to be converted back into static pressure behind in the wake which raises the pressure drag.

yes; steering linkage, track bar, control arms, drive shaft(that's just the front). But that's why the skid plate cover's about 80-90%(what it's not covering is the steering linkage ends, knuckles, springs, and roll bar end links) of the front end allowing for the dead space between it and the gas tank.

all components of the rear suspension are in board of the frame

*The airdam forces air to go over,around,or below the dam,capturing an inverted pool of dead air between the bottom of the dam and bottom of vehicle.This 'pool' of air travels along with the vehicle with 'active' air moving unobstructed below it to the rear,and beside the vehicle in a straight path with no circulation.

yes, my skid plate is pointed downward; unobstructed airflow yes

*By increasing the velocity of the active air under the vehicle,it's static pressure is reduced which helps retard lift.

already said that earlier to sven; it's part of bernoulii's principle

*The air under the vehicle can never be as 'active' as air on the sides or top due to interference with the road boundary,but the airdam can help 'optimize'
conditions,even with a perfectly smooth belly pan.

yes

*ANY lift is induced drag,and the engine will have to burn more fuel to overcome it.

yes, along with the big parachute of a wake the jeep is pulling behind it.

*Since Dr.Alberto Morelli's Pininfarina CNR 'banana' car of 1978,it's been possible to design zero-lift automobiles with excellent directional stability.

yes, within what a manufacture originally designed it for; at a certain point flow separation will happen, just probably not reached by joe q public.

as for the sides the hood channeling air to the sides, 3.25" fender flares, side steps, door hinges, and mirrors help to produce big wakes along each side.