GM Truck Aero Article

[vteco]

Saw this somewhat general write-up. The photos were interesting though, and the mention of the gap between cab and bed was singled out for particular mention.

GMC Pickups 101: Busting Myths of Truck Aerodynamics

[aerohead]

Current RAM 1500s have molded rubber gap-fillers on the sides. I can't tell about the forward bulkhead, as, the truck had a tonneau cover which prevented a 'view' .
--------------------------------------------------------------------------------------
On the 2017 wind tunnel trip, I installed a tear-off cardboard and duct tape ( cad ) gap-filler, for top and sides of Spirit ( the bottom was already paneled in with the belly pan ).
It indicated a delta-negative Cd 0.016 drag reduction.
In the 2014 configuration, that would have meant a Cd 0.2515 on the road.
Cd 0.2380 with the replacement SCCA racing mirrors.
Cd 0.2280 if my back could have survived working underneath to do the belly pan repair.
--------------------------------------------------------------------------------------
If Spirit were a BEV, the heat flux would be 350% lower than for the extant ICE powerplant, allowing the cooling inlet to be downsized, bullet-valve gap reduced, or 'shuttered' accordingly, placing Spirit in Cd 0.2110 territory.
For 95% of Ford Lightnings, Chevy Silverado EVs, Rivian RT1s, and the upcoming RAM REVs, all these trucks could be modded to Cd 0.211 as well.
If one could 'stand the look', range anxiety would vanish from the face of the earth.
I can't say anything quantitative about Cybertruck. Elon kinda surrendered aerodynamics with the hard edges, leaving Franz Von Holzhausen and Robert Palin severely constrained on what they could do.