SPA XC90 Drag Coefficient Discrepancy

thrggdf635 · Post by **thrggdf635** » 17 Dec 2025, 07:23

Looking at the reporting/literature on the SPA xc90, the drag coefficient was reported at 0.30 early on, but this was altered to 0.33 after 2017 or so. Does anyone know the cause of this discrepancy and whether any material changes to the design caused it, or was it just updated testing/CFD meshing etc?

Post by **volvolugnut** » 17 Dec 2025, 07:38

That is an interesting question. A 10 percent increase is huge. I doubt minor changes to the body and trim would create such a change or if engineers would knowingly make a change to add 10 percent drag.
I think original number may have been wrong. Only semi educated guesses. Welcome to MVS.
volvolugnut

Post by **matthew1** » 17 Dec 2025, 12:33

Tire width and roof rack can affect this. I'm afraid the discrepancy reason between early testing and later testing difference may never be known. Here's a post from 2017 mentioning .30 viewtopic.php?t=79842