Infineum on Quenching LSPI

[Virtus_Probi]

My apologies if anybody else has posted this...

http://www.infineuminsight.com/insight/nov-2016/quenching-low-speed-pre-ignition

. My executive summary;
1. Higher calcium increases LSPI
2. Magnesium is LSPI-neutral
3. Sodium in the presence of calcium increases LSPI (sorry Valvoline fans)
4. Increasing ZDDP concentration inhibits LSPI (!)
5. Antioxidants, Viscosity Modifiers, and SAE grade appear to have little to no effect upon LSPI

The finding concerning ZDDP makes dealing with DIT engines even more fun, as many people are looking to use low SAPS oils to help minimize intake valve deposits. But, increasing the ZDDP concentration can help to prevent LSPI occurrence...we're looking at a classic engineering tradeoff here!
I happened upon this article while I was trying to figure out if I should care that M1 0W30 ESP has about 1600ppm of Ca compared to roughly 1000ppm for the 5W30 version...looks like, in the particular GM engine that was used for this testing, that is possibly enough of a change to make a significant difference.

 

[wemay]

Nice post! thanks.

 

[Virtus_Probi]

Originally Posted By: wemay
Nice post! thanks.


I just KNEW my buddy wemay would show up here!
;^)
Hope you are doing well, my friend.

 

[BigD1]

Toyota D4S with self cleaning feature. It's a dual injection system, port and direct, and now it cleans the injectors too. Toyota had this problem figured out a decade ago whether they knew it or not at the time.

 

[Virtus_Probi]

Originally Posted By: BigD1
Toyota D4S with self cleaning feature. It's a dual injection system, port and direct, and now it cleans the injectors too. Toyota had this problem figured out a decade ago whether they knew it or not at the time.


This can probably help keep the intake valves clean when the port injection is used every so often, but will not help with LSPI when direct injection is used.
I believe that Toyota decided to let other automakers use their patented system royalty free and it will definitely be showing up in the next generation of Ford Ecoboosts. I was pretty depressed when I found that the 2.0l engine in the Toyota/Subaru FT86/BRZ had the dual injection system, but the 2.0l turbo in my Forester and NA 2.0l in my daughter's Impreza did not.

 

[Dan55]

Toyota reformulated their oil (OW20) for LSPI http://papers.sae.org/2014-01-2785/ for their 2.0T 8AR-FTS, If they carried it over to other grades it might be a consideration.

 

[wemay]

Originally Posted By: Virtus_Probi
Originally Posted By: wemay
Nice post! thanks.


I just KNEW my buddy wemay would show up here!
;^)
Hope you are doing well, my friend.


Haha, yes, doing well thanks. Hope you are as well my friend.

 

[Olas]

So it looks like oil burners need more zinc and less calcium..

Aren't the majority of DI vehicles new enough that they shouldn't be leaking engine oil into the combustion chamber? Underlying design problems? Oil control rings?

With sufficient separation of lube and intake charge the laps should be a non issue.

 

[Solarent]

Originally Posted By: Olas
So it looks like oil burners need more zinc and less calcium..

Aren't the majority of DI vehicles new enough that they shouldn't be leaking engine oil into the combustion chamber? Underlying design problems? Oil control rings?

With sufficient separation of lube and intake charge the laps should be a non issue.


It has nothing to do with the age of the engine or leaking oil. There will always be a thin film of oil on the cylinder walls. Here's a video on the subject:

 

[Virtus_Probi]

Originally Posted By: Dan55
Toyota reformulated their oil (OW20) for LSPI http://papers.sae.org/2014-01-2785/ for their 2.0T 8AR-FTS, If they carried it over to other grades it might be a consideration.


I'd sure look at it if they made something 0/5W30/40ish!!

 

[Ohle_Manezzini]

0w20 burns a little in most new engines