Why Don’t Cars Use V4 Engines Anymore? Why Do Modern Cars use Inline 4 Engines instead of V4 Engines? Ends up, we did utilize V4 Engines in the past, but the included intricacy and cost, had not been worth the small gain in compact dimensions, as autos do not really battle with Engine Bay Space. As for Motorcycles, the Compact nature of the V4, has made it a popular option that stood the examination of time! So fear not V4 Lovers! They will not be going vanished at any time soon!