With the engine running at a standard speed and load the compression ratio is increased until detonation is detectable. The amount of resistance that a fuel has to detonation. Now, as leaded fuels are not allowed to be sold in many areas, other, generally more expensive and less effective as compared to cost, fuel additives are added. Lead was an extremely effective knock suppressant. By law, fuels intended for on road use have been limited in maximum lead content for some time.
Lead poisoning causes brain damage.
Most fuel has been unleaded for quite some time. People born after the late 70's must be much smarter than the older people. Back to Fuel, Octane and HP Page Register for Factory Pro Tuning email updates 1. Enter email address 2. By Rocky Cherry on his EX500.