Should fuel dilution impact your oil choice?

[Brian Barnhart]

Originally Posted By: Clevy
Originally Posted By: Brian Barnhart
Originally Posted By: Brian Barnhart
Originally Posted By: OneEyeJack
If you're talking high performance and want to deal with fuel dilution there is an oil company, RLI that has developed oil specifically formulated to deal with fuel dilution for high performance turbocharged engines. They developed it in cooperation with a customer that owned an Audi and Terry Dyson the analysis work.

You can actually call RLI and talk to them about the oil. You probably don't need to go to such lengths to take care of fuel dilution for the average daily driver but here is a solution if you choose to go that way. The results were very good and they were all verified by very detailed UOA's done by Terry.


This ^^. I recall when that work was taking place; several years ago now. Not sure if newer direct injection engines have similar levels of fuel dilution or not.

I'll also add that fuel dilution levels rose very soon in the OCI, and more frequent oil changes did virtually nothing to offset the problem if I remember correctly.


One other point regarding the earlier work (if I remember correctly); wear metals were still above normal even when a thicker oil viscosity was used to compensate for thinning from fuel dilution. (Apparently the presence of fuel was negatively affecting more than just the oil's viscosity).


Which on its own means nothing,absolutely nothing and isn't a reason to switch anything.


Perhaps I didn't make it clear enough. OneEyeJack made two very important points.

RLI has experience with fuel dilution problems and markets oils that serve well in those applications. As OEJ said, give them a call if you want to gain from their experience.

Terry Dyson was also involved in the work and has knowledge in that area as well. He is also a source of good information on the subject.

Anyone with a DI/fuel dilution issue should consider contacting someone with experience finding solutions to the problem, and/or do a search for the old threads here concerning the subject as has been suggested.

I remember the hard work done at the time by those above. I simply tried to relay what I remember about the work, and point out that a solution wasn't found in the oil isle at Walmart or Auto Zone, or even through more frequent oil changes.

 

[Garak]

I remember reading much of that back in the day and did converse with some involved through PM. Of course, whether or not fuel dilution is that much of an issue remains to be seen. But, RLI and Terry Dyson certainly spent a lot of effort on the matter.

 

[badtlc]

Originally Posted By: Quattro Pete
Originally Posted By: badtlc
No. I do a lot of city driving. Running premium fuel eliminated the issue for me as it leans out the A:F ratio.

Doing a lot of city driving is no problem, just as long as it's not just 3 miles and then park for 8 hours, like in my wife's case. Today was a fairly warm day, and at the end of these 3 miles, the oil temp hasn't even reached 140F. And during winter, it's even worse.

I can't imagine premium fuel making much difference. Looking at various UOAs, I can't see any such pattern.




Look at the skyactiv UOAs. There has been a VERY clear difference established between those who run premium and those who don't. Premium has resulted in no fuel dilution issues.

 

[edyvw]

Originally Posted By: badtlc
Originally Posted By: Quattro Pete
Originally Posted By: badtlc
No. I do a lot of city driving. Running premium fuel eliminated the issue for me as it leans out the A:F ratio.

Doing a lot of city driving is no problem, just as long as it's not just 3 miles and then park for 8 hours, like in my wife's case. Today was a fairly warm day, and at the end of these 3 miles, the oil temp hasn't even reached 140F. And during winter, it's even worse.

I can't imagine premium fuel making much difference. Looking at various UOAs, I can't see any such pattern.




Look at the skyactiv UOAs. There has been a VERY clear difference established between those who run premium and those who don't. Premium has resulted in no fuel dilution issues.

So premium fuel has much less sulphur then regular or mid-grade? I would not say that based on my UOA.

 

[Clevy]

Originally Posted By: edyvw
Originally Posted By: badtlc
Originally Posted By: Quattro Pete
Originally Posted By: badtlc
No. I do a lot of city driving. Running premium fuel eliminated the issue for me as it leans out the A:F ratio.

Doing a lot of city driving is no problem, just as long as it's not just 3 miles and then park for 8 hours, like in my wife's case. Today was a fairly warm day, and at the end of these 3 miles, the oil temp hasn't even reached 140F. And during winter, it's even worse.

I can't imagine premium fuel making much difference. Looking at various UOAs, I can't see any such pattern.




Look at the skyactiv UOAs. There has been a VERY clear difference established between those who run premium and those who don't. Premium has resulted in no fuel dilution issues.

So premium fuel has much less sulphur then regular or mid-grade? I would not say that based on my UOA.



No.
He's saying that premium fuel eliminates enrichment due to knock which could be a significant amount of fuel added.
Running rich to prevent knock,if that condition was present often could account for significant fuel dillution.

 

[edyvw]

I understand that. Still, sulphur is main culprit here. My engine runs only on premium, but still TBN in M1 0W40 went from 11 to 2.9 after 5K. Culprit is sulphur, and until that issue is resolved (hopefully in 2017) 5K OCI using high quality synthetic oils is for me best option to address these issues.

 

[Triple_Se7en]

Originally Posted By: 2010_FX4
It should not impact your choice, but it should impact your OCI...


Bingo
Yatzee
Kismet

Change the oil more often.

 

[Garak]

Originally Posted By: edyvw
I understand that. Still, sulphur is main culprit here. My engine runs only on premium, but still TBN in M1 0W40 went from 11 to 2.9 after 5K.

I think the point was that there might be a noticeable difference in vehicles where running regular is a possibility and even then, in only some of those examples. You have no other baseline with which to compare. I'd also wonder what kind of difference might be noticeable in such vehicles when comparing E10 to E0. In most Canadian jurisdictions, for instance, regular is E10 and premium can be (and most often is) E0. Certainly, sulphur is the biggie here, as you indicated. But, the individual cannot really control that, since ULSG isn't really an individual option unless we all head to California to fill.

 

[bluesubie]

Originally Posted By: Shannow
Terry alluded to it yonks ago, that fuel dilution wasn't simply a thinning out like the kero in the WW2 aero engine sumps, but was an actual reaction phenomena that took place, and was sometimes, depending on oil irreversible.

I believe that the choice of oil will help in the above, but have no experience or idea where to start...other than to use the google search of BIOTG, using the terms "dillution audi terry", as the Audis were the early adopter of destroying oils back in the day.

I found some good posts on here and Audiworld by doing a google search on "fuel dilution audi rs4 Terry". I also found the paper by RLI and Chevron that was presented at STLE Cleveland in 2008.

There was a lot of great information regarding fuel dilution, although I still couldn't find Terry's specific comments on it. They might be buried in one of RIRS4's uber threads here.

Fuel dilution is becoming a concern for owner's of new Subaru Direct Injection Turbo engines because uoa's are showing that the oil is pretty polluted with fuel at relatively short intervals. One way WRX owners are dealing with it, while still sticking to the recommended
"5W-30" is to run an ACEA A3/B3 or C3 oil so the oil stays in grade. Premium is required for the WRX and Forester turbo, so I don't believe that makes a difference here.

Blackstone doesn't think it's a problem even if the viscosity is a low 20 grade, flashpoint is shot and fuel is elevated as long as the uoa wear numbers are normal. Even based on one uoa.

There have been a few Blackstone vs. OAI comparisons on nasioc.com due to the different fuel dilution testing methods (no surprises on the results).

The unfortunate issue with following some of the recommendations mentioned here and elsewhere (like using thicker oil or using non certified oil) is that people are afraid to experiment for fear of warranty issues. Of course, some of these same people will do a reflash and remove the flash before they go to the dealer if they have an engine issue.

 

[Clevy]

Originally Posted By: bluesubie
Originally Posted By: Shannow
Terry alluded to it yonks ago, that fuel dilution wasn't simply a thinning out like the kero in the WW2 aero engine sumps, but was an actual reaction phenomena that took place, and was sometimes, depending on oil irreversible.

I believe that the choice of oil will help in the above, but have no experience or idea where to start...other than to use the google search of BIOTG, using the terms "dillution audi terry", as the Audis were the early adopter of destroying oils back in the day.

I found some good posts on here and Audiworld by doing a google search on "fuel dilution audi rs4 Terry". I also found the paper by RLI and Chevron that was presented at STLE Cleveland in 2008.

There was a lot of great information regarding fuel dilution, although I still couldn't find Terry's specific comments on it. They might be buried in one of RIRS4's uber threads here.

Fuel dilution is becoming a concern for owner's of new Subaru Direct Injection Turbo engines because uoa's are showing that the oil is pretty polluted with fuel at relatively short intervals. One way WRX owners are dealing with it, while still sticking to the recommended
"5W-30" is to run an ACEA A3/B3 or C3 oil so the oil stays in grade. Premium is required for the WRX and Forester turbo, so I don't believe that makes a difference here.

Blackstone doesn't think it's a problem even if the viscosity is a low 20 grade, flashpoint is shot and fuel is elevated as long as the uoa wear numbers are normal. Even based on one uoa.

There have been a few Blackstone vs. OAI comparisons on nasioc.com due to the different fuel dilution testing methods (no surprises on the results).

The unfortunate issue with following some of the recommendations mentioned here and elsewhere (like using thicker oil or using non certified oil) is that people are afraid to experiment for fear of warranty issues. Of course, some of these same people will do a reflash and remove the flash before they go to the dealer if they have an engine issue.




That re flash to stock doesn't fool them anymore. They see the dead spot where there's no accumulated data

 

[Shannow]

From Honda, "Study on estimation Method of Anti-Oxidation Performance for Engine Oil Deterioration Monitoring System

Quote:
Oxygen in the air is the first factor that can be indicated as a cause of OIT deterioration. Engine Oil is constantly exposed to oxygen, and the base oil and additive react directly with oxygen, causing a deterioration of the OIT. NOx is a second factor in deterioration. NOx is highly reactive and may rapidly cause an oxidation reaction when it comes into contact with engine oil. Unvurnt fuel can be indicated as a third factor. Unburnt fuel, present for example in blowby gasses, is reactive, and may cause an instantaneous reaction when it comes into contact with engine oil, again causing deterioration of OIT


(OIT - Oxidation Induction Time)

That second point (NOx), is my theory on where varnish is produced, in the crankcase, where very hot oil is sprayed from the big-ends into a climate of NOx, CO, and other reactive species.