What level armor did you have on these?
I noticed the ammount of bullets to lower the car varies on armor. For ex my 2nd character is level 48 so I can only get the medium armor. I shot about 25 times on one wheel then it lowered. But my other character is a higher level & it takes way more bullets to lower my car with %100 armor. One car I couldn't lower tho was the sultan, I only got the front wheels down & once I started shooting the rear wheels, it exploded. I tried this 3 times ending the same way. It get's annoying. Btw the sultan had %100 armor & yet it still exploded.