LSPI is characterised by igniting before the spark plug fires so pulling timing doesn't work, don't see why port injection would be immune?And the emphasis should be on the fact that this is a DI phenomenon, a conventional port injected engine operated in the same manner does not experience LSPI.
Probably due to a higher level of added Viscosity index improver.Coincidentally M1 0W20HM is thicker than the 5W at operating temp. It makes the 5W look redundant. I can't speak to viscosity stability between the two. Maybe the 5W is thicker after a while than the 0W.
LSPI is characterised by igniting before the spark plug fires so pulling timing doesn't work, don't see why port injection would be immune?
Lubrizol said:Downsized gasoline engines, coupled with gasoline direct injection (GDI) and turbocharging, have provided an effective means to meet both emissions standards and customers' drivability expectations. As a result, these engines have become more and more common in the passenger vehicle marketplace over the past 10 years. To maximize fuel economy, these engines are commonly calibrated to operate at low speeds and high engine loads well into the traditional knock-limited region. Advanced engine controls and GDI have effectively suppressed knock and allowed the engines to operate in this high efficiency region more often than was historically possible. Unfortunately, many of these downsized, boosted engines have experienced a different type of uncontrolled combustion. This combustion occurs when the engine is operating under high load and low speed conditions and has been named Low Speed Pre-Ignition (LSPI).
Lubrizol said:This is the situation for drivers when low speed pre-ignition (LSPI) strikes in turbocharged gasoline direction injection (TGDI) engines. As we detailed recently, newly available lubricants certified under API SN Plus can stop LSPI before it happens. And service shops bear a responsibility to educate everyday drivers on why choosing those higher performance lubricants is important.
But there’s another layer to this story, and it’s one that isn’t fully told with API SN Plus.
The lubricant industry’s understanding of LSPI and our approaches to eliminating it in TGDI engines are still evolving. With the development of the LSPI test that helps certify API SN Plus lubricants, we’ve found one way to accomplish that goal.
That doesn’t mean there aren’t others.
I understand the marketing agreement GM has again with Mobil lubes however they also have agreements with oil manufacturers who pay GM a royalty to get the Dexos 1 Generation 2 (and beyond) license...if any Dexos 1 Generation 2 oil would work why wouldn't GM just say that...but they mention low calcium for a reason...Because they have a contractual relationship with Exxon/Mobil. All of their high performance cars come with Mobil 1 and Mobil 1 printed on the oil cap. And the AC/Delco recommendation is pretty obvious. That is a GM brand. The Dexos certification is given to any brand of oil that meets current GM specs. Here is a list straight from GM of Dexos approved oils. You should be able to find one from this list. https://www.gmdexos.com/brands/dexos1/index.html
A dexos1 Gen2 approved oil will be all you need. Beyond that, if you want to find the d1G2 oil with the least Calcium, you can visit https://pqia.org/ .I do realize what you are saying but I'm only concerned for the time being with GM's own recommendation that a low calcium, full synthetionly be used in the 2.0 Turbo engine...