Originally Posted by Gene W
They aren't any lower, they just have the hot pants kits on them that give them the appearance of being lower.
If they have fitted wheels and tires that are effectively smaller diameter, they may be marginally lower. I don't know if they are still running lower profile automotive tires on conversions like they did in the old days, but I wouldn't want one configured that way. If they lower the profile, they should increase the wheel diameter in a true +1 or +2 configuration, which would have no effect on ride height.
The front air dam is a two edged sword in that it diverts some of the air from going under the van and creating drag on the rough underside but also creates drag by presenting a larger front profile for the van. There may actually be some benefit to the lift generated by the air going under the stock van in the form of less rolling resistance.
The fender flairs and running boards would have to be all drag. I can see no aerodynamic benefit to them.
I think these items are more of a styling exercise than aero aides, which brings us back to the added weight that conversions carry. That's always a bad thing.
Gene
Well, seeing that my 95 conversion van gets better mileage than your Chateau, that seems to blow your theory out of the water
My mileage has never varied off the 11-14 mpg since new. Even after the switch from the stock wheels and tires to the ones I have now: 15x8.5's front, shod with 235/70'snd rear with 15x10's shod with 275/60's. It now sits about 1-2" lower with these than the 29" stockers. Handles a little better too with it's wider stance. Looks a damn sight better now that the tires fill up the fender flares.
