According to a note on 2217c01pb01 the part number 2217 refers to the car base,
not the body, which is why this part number looks like a different colour race
car, but is in fact a totally different car:
If you search for 2217c03pb01 you're redirected to 2218c03pb01 where a note
explains that 2218 is the body. This makes way more sense; referring to the composite
part by the sub part that differentiates them.
Instead here the c01 refers to the colour of the base, and this part number exists
in 4 different body colours...
The way the "Duplo Car" is numbered makes sense; 2218 denotes the body,
the recognisable part of the car, and c## indicates the colour.
With that logic 2217c01pb01 should change to 2240c01pb01 and duploracer01 should
change to 2240c02pb02. Ideally though the pb numbers are changed, so pb01 = Number
1 pattern, and pb02 = Number 2 pattern...
2217c02pb01 should then be 2244c01pb01 since 2244 is the body of that car.
Question remains what to do with duploracer02. Is anyone willing to open one
up to see if the body with the single stud has a new mold number?
That turned into a longer post than I thought... Hope it makes sense?