What is the meaning of LSPI?
LSPI is an acronym – Low-Speed Pre-Ignition. It’s a type of engine knock that occurs in turbocharged gasoline direct-injected engines under low-speed, high-torque conditions and is more destructive than typical engine knock.
What causes Low-Speed Pre-Ignition?
Under normal operation, spark-triggered ignition is timed to work in tandem with downward piston momentum. LSPI occurs when an oil/fuel droplet hiding in the piston crevice launches into the combustion chamber and ignites the fuel/air mixture too early. The resulting force clashes with the upward moving piston and can cause damage like that on the piston shown.
LSPI Testing
This specific test records an oil’s ability to prevent LSPI. Five LSPI events can occur before the motor oil fails. AMSOIL Signature Series, XL, and OE Synthetic Motor Oil all passed with ZERO pre-ignition events, proving they provide outstanding protection for turbocharged direct-injected engines.
More Details
This is a hot topic in the lubricant industry because it can destroy pistons and connecting rods. Auto manufacturers need to extract every bit of fuel economy from the vehicles they produce in order to meet increasingly stringent government regulations. Manufacturers can make fuel-economy gains in today’s vehicles by adjusting vehicles’ programming, but those changes would also almost guarantee LSPI would occur. The potentially disastrous effects are one of the driving forces in the scramble to create the new motor oil specifications, API SP/ILSAC GF-6 and GM dexos1 Gen 2. To gain about 10 percent more fuel economy, auto manufacturers will eventually reprogram their vehicles to maximize mpg, inviting LSPI and relying on motor oil to prevent catastrophic results. While we expect this switch will be a couple of years out yet, we have dedicated considerable resources to confront the problem. The testing has concluded and the results are in: all AMSOIL synthetic motor oils provided 100 percent protection against LSPI in the engine test required for the GM dexos1 Gen 2 specification.