Since you are googling up, Google LSPI ( Low Speed Pre Ignition) and you will get why people say that. It comes back to peak cylinder pressures like the post from Mark yesterday. Low speed pre-ignition (LSPI) is a premature combustion event, occurring prior to spark ignition in turbocharged, downsized gasoline vehicles. As the name implies, it occurs when engines operate at low speeds and high loads. It can result in extremely high cylinder-pressures and can lead to heavy knock. At a minimum, LSPI can generate an audible knocking noise noticeable to the driver. Repeated exposure to these conditions can cause engine hardware failure, including broken spark plugs and cracked pistons Sent from my SM-G781B using Tapatalk