LSPI and Engine Oil

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Originally Posted By: buster
Back in 2012, Mobil 1 reduced the SA of Mobil 1 to .8%. This is when they went to a Mg/Ca detergent system. I wrote to them about the reduced TBN and impact it may have on oil performance. This was their response. (2012)

Quote:
"Thanks for your message. We appreciate the feedback. A slight reduction in ash is desirable for advanced engine technology such as gasoline direct injection (GDI) engine and passenger car diesel engines. With GDI engines, higher levels of ash appear to result in a higher occurrence of Low Speed Pre-Ignition. The industry is currently developing tests and specifications to address Low Speed Pre-Ignition. In the future, passenger car engine oil specifications such as ILSAC GF-6 and dexos1 (next generation) are likely to have requirements such as lower ash to address Low Speed Pre-Ignition.

As for TBN retention, it is only a single parameter that provides an indication of the used oil condition. A reduction in TBN is an indication that the overbased detergent is doing its job by neutralizing acids that form as a result of combustion. TBN should be used in combination with other used oil parameters such as oxidation, nitration, TAN (Total Acid Number), ICP metals, D4684 MRV viscosity, and D445 kinematic viscosity to determine the overall condition of the used oil.

Finally, in our experience in severe-service Las Vegas field testing, Mobil 1 engine oil TBN levels typically do not drop below 2 for vehicles with 15,000 mile oil drain intervals. Furthermore, it is our experience that those oils tend not to drop any lower when we continue to 20,000 mile oil drains.

We hope this information was both helpful and informative. Thanks again for reaching out, and for your continued support of Mobil 1."





Wow, XOM was really looking ahead while we were noticing by used oil analysis that Castrol was increasing calcium in some of their formulas during the last several years!
 
Originally Posted By: Floydian
Originally Posted By: SR5
Someone once said that higher zinc (ZDDP) oils are less prone to LSPI. Does anybody know if this is correct ?

If so the Euro 0W40 oils usually have about 1000 ppm Zn as opposed to ILSAC oils with 800 ppm Zn (or less).


Check this out:

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



Thanks Mate, exactly what I was after

Quote:
Infineum increased the phosphorous level from 0.05% to 0.19% in the test oil. ZDDP has an exponential decrease in LSPI activity - higher levels of ZDDP reduced over 90% of LSPI events compared to the number that occurred with the 0.05% ZDDP oil, confirming ZDDP as an LSPI quencher


Reading their graph, it roughly looks like to me, that going from GF-5 Phos levels (~ 0.08%) to Euro Phos levels ( ~ 0.1%) cut the the number of LSPI events in half.
 
Originally Posted By: SR5
Originally Posted By: Floydian
Originally Posted By: SR5
Someone once said that higher zinc (ZDDP) oils are less prone to LSPI. Does anybody know if this is correct ?

If so the Euro 0W40 oils usually have about 1000 ppm Zn as opposed to ILSAC oils with 800 ppm Zn (or less).


Check this out:

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



Thanks Mate, exactly what I was after

Quote:
Infineum increased the phosphorous level from 0.05% to 0.19% in the test oil. ZDDP has an exponential decrease in LSPI activity - higher levels of ZDDP reduced over 90% of LSPI events compared to the number that occurred with the 0.05% ZDDP oil, confirming ZDDP as an LSPI quencher


Reading their graph, it roughly looks like to me, that going from GF-5 Phos levels (~ 0.08%) to Euro Phos levels ( ~ 0.1%) cut the the number of LSPI events in half.


I have to admit that I did a little garage chemistry and added bits of ZDDP and moly additives during recent oil changes after reading some of the LSPI studies. Won't bother with that using dexos1 Gen 2 oils.
 
V_P, the interesting thing about ZDDP quenching LSPI is that it follows a exponential curve. So a little more goes a long way.

Where as Ca detergent initiating LSPI is a linear curve (line). So bigger changes in chemistry for less of an effect.

The fact that ZDDP is an anti-wear agent (protects the metal) and an antioxidant agent (protects the oil) is just bonus points.

Those Euro cars have been running 1000 ppm zinc / Phos oils for decades, yet their exhaust cats survive fine.
 
Originally Posted By: Virtus_Probi
Wow, XOM was really looking ahead while we were noticing by used oil analysis that Castrol was increasing calcium in some of their formulas during the last several years!

To back that point up, my 2018 DI-Turbo 1.5L GM Equinox Owner's Manual specifically points out that I can use any AC-Delco or Mobil 1 product (even if old generation dexos1 Gen1), or I must select a dexos1 Gen2 if going to another brand. Thats telling. GM believes Mobil 1 has been addressing LSPI OK even before the latest dexos1 Gen2 LSPI tests emerged.

Liking that Infineum web page on LSPI. Lays it all out. However, even they concede there is nothing like a real LSPI engine test in a spec to be sure.
 
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DI engines, both turbo and naturally aspirated will suffer from intake valve deposit build up. Are these oils becoming less powerful in cleaning ability in order to reduce LSPI?
 
Originally Posted By: PimTac
DI engines, both turbo and naturally aspirated will suffer from intake valve deposit build up. Are these oils becoming less powerful in cleaning ability in order to reduce LSPI?
DI engines suffer because fuel doesn't continually wash over the intake valves as in port-injected engines. Oil type has little to do with it.
 
Originally Posted By: SR5
V_P, the interesting thing about ZDDP quenching LSPI is that it follows a exponential curve. So a little more goes a long way.

Where as Ca detergent initiating LSPI is a linear curve (line). So bigger changes in chemistry for less of an effect.

The fact that ZDDP is an anti-wear agent (protects the metal) and an antioxidant agent (protects the oil) is just bonus points.

Those Euro cars have been running 1000 ppm zinc / Phos oils for decades, yet their exhaust cats survive fine.


Yes, exactly what I was thinking when I bought some ZDDP additive...ride that sharp slope down a bit! I felt that my cats would be fine with the small amount I was adding and I'm worried more about pistons cracking now than replacing the cats way down the line.
It will be interesting to see if some of the Gen 2 oils raise the ZDDP as much as they can for LSPI while still meeting the API SN limits...
 
Originally Posted By: oil_film_movies
Originally Posted By: PimTac
DI engines, both turbo and naturally aspirated will suffer from intake valve deposit build up. Are these oils becoming less powerful in cleaning ability in order to reduce LSPI?
DI engines suffer because fuel doesn't continually wash over the intake valves as in port-injected engines. Oil type has little to do with it.


Yes, I have been running valve cleaner in through a vacuum line to help fight this problem and need to run it through my daughter's non-turbo DI Subie soon.
The ultimate solution here is to use a combined PFI/DI system like some Toyotas, Subarus, and Fords use.
 
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