whitedog
Veteran Member
Re: PD Oil Analysis Thread
Not sure who is right, but I certainly understand the SUNRGs part better.
(Twoslick) The wear metal particle concentrations that show up in oil analysis are mainly the result of dissolved ions and minute wear metals less than 1.0 um. The use of bypass filters does NOT skew these results to any significant degree.
Engines using by-pass filters show significantly lower wear rates, due to a reduction in the size and average concentration of insolubles in the lubricant. These insolubles include abrasive polymeric materials generated by oxidation and nitration, in addition to agglomerated soot particles and the occasional large silicon and/or wear metal particle.
The effectiveness of by-pass filtration in reducing actual wear rates is well documented in controlled field tests of commercial diesel engines. Go to www.SAE.org and do a literature search of lubricant and filtration related papers generated in the past ten years.
I liked SUNRGs part here. I'm not against learing new woids and phrases but the first was a bit tough for the average person to read.(SUNRG) An engine with brand new motor oil (virtually containing no contaminants) will produce wear metals at a given <u>linear</u> rate. As the engine's operating hours accumulate, oil contaminant levels increase, and at some point the presence of the contaminants increases the rate of engine wear (greater than linear wear rate).
When an oil is only in service for a short period of time, the oil contamination is at such a low level that it <u>does not</u> significantly effect wear rate (wear rate remains linear).
If the very low level of oil contamination a healthy TDI creates in 10k significantly effected engine wear rates, then we would see marked increases in TDI wear rates when 5k OCI and 10k OCI UOAs are compared - but this is not the case.
During 10k OCIs in TDI engines, the oil contaminant level does not reach the point where it impacts (causes greater than linear) wear rates - i.e. <font color="red">at 10k OEM filtered oil it is still functioning optimally</font>. This reality is the rational behind the 10k OCI specification, and it has been proven to be conservative time and time again with TDI UOAs (real world TDI specific data).
<font color="red">Bypass oil filtration enables oil in TDIs to perform optimally <u>beyond</u> 10k.</font> Based on the TDI UOA data I've seen, I do not believe bypass filters significantly reduce TDI engine wear during short (10k or less) OCIs. Reduced UOA indicated contaminant levels (bypass filtered) during short OCIs, IMO are more plausibly attributable to contaminant dilution (bypass filters increase the TDI oil capacity by a minimum of 20%) and contaminant filtration.
Not sure who is right, but I certainly understand the SUNRGs part better.