ICE vehicle fires take about 1000 gallons, and the average fire hydrant puts out about 500-1000 gallons per minute. Structural fire engines carry about 1000 gallons and the heavy duty nozzles and ground monitors/deck guns put out 500-1000gpm. This is a LOT of water for a vehicle.
More like 300-400 gallons for your average urban engine. That's enough (with not much to spare) to knock down your average ICE car fire, but it's really there to allow the crew to get to work while they ship a hydrant.
