[XtremeRevolution]

You guys with the newer GDI turboed 1.4 engines should not have to worry about LSPI unless you tune the precautionary code out of the ECM.s .

Todays oils with high flash point tolerances minumizes the possibility of LSPI from windowing a engine block ..

There are other concerns about preignition though .
Connecting rod ends have been letting go under the stresses of preignition ..

LSPI is low-speed pre-ignition. You kind of contradict yourself by saying people don't have to worry about LSPI, then saying that there are other concerns about pre-ignition.

Flash point has little or nothing to do with LSPI. LSPI is caused by the rapid oxidation of oil droplets. That oxidation comes from a number of sources. I bought an SAE case study (that has been widely misinterpreted) last year that outlines some testing performed by Toyota to try to reduce the frequency of LSPI. To quote the article directly, "Toyota has reportedthat the oxidation stability of engine oil can be a dominant factor of its auto-ignition, which is a function of its base oil andadditive components."

Unfortunately, the test was not at all scientific. Toyota found that reducing calcium-based detergents reduced the frequency of LSPI, but they didn't just change the detergents, they also changed the base oil (and therefore volatility) of the oil, among other factors. Their data also suggests that this was not a scientific comparison. For example, they have a list of products tested.

Product A, with 0.24% Ca, 0.08% P, and 0.07% Mo tested at 1.00 LSPI frequency; the reference oil.
Sample J, with 0.20% Ca, 0.09% P, and 0.05% Mo tested at 0.17% LSPI frequency.

If the mere reduction of Ca results in lower LSPI frequency, it should take more than just 0.04% to drop LSPI frequency to ~1/6 that of the reference oil. They go on to state that other factors involve increasing the amount of P in ZnDTP and increasing the amount of Mo in MoDTC or an anti-oxidant with Mo, which further validates that the problem is oxidation stability, and all other changes are a consequence of that.

If anyone else wants to buy the study, here's the link: Engine Oil Development for Preventing Pre-Ignition in Turbocharged Gasoline Engine

 

[XtremeRevolution]

You 've answered my ? Andrei .
What exactly is detonating during LSPI ?
1 should also remember that this phenomena is a rare instance that can happen when going to full throttle from a low speed and low RPM .
change your oil regularly ...

During LSPI, it's the engine oil that's pre-igniting, which in turn ignites the fuel.

Note that this is only with respect to engine oil. There are more factors that affect LSPI, which include the tune, the fueling hardware design, temperature, pressure, and solid deposits around the combustion chamber.