Fuel dilution - how harmful, how much wear?

[KrisZ]

PFI has pretty much resolved fuel dilution issues from the carbureted days, we are now back full circle. Maybe not as bad as flooding the engine during a cold start, but still, some engines are bad.

This thread has mainly focused on film thickness and wear associated when that thickness fails due to fuel.

However, since fuel is a good detergent, I do wonder its effect on the anti wear sacrificial layer from oil additives. Does fuel strip that layer down? Makes it harder to form?

So perhaps an argument can be made that if the MOFT has not been affected, we shouldn’t worry about fuel dilution, but if the antiwear additive layer is affected by fuel contamination, then the boundary wear protection could be compromised.

And we all know new engines operate in boundary conditions a lot more than the older engines, even when MOFT is still good.

 

[OVERKILL]

I agree, but its not a definitive statement driven by test data. Its like me or you saying it. Its in their pre-amble.

How bad? Does it shorten engine life? By how much? How much dilution is too much, etc. We still don't know. This study does not change that. I would actually like to know.

Again, I am not disagreeing with your position on dilution, but said Russian article was presented here as a scientific comprehensive study on the topic, but I don't believe it is. It appears to be a study on measuring dilution, not its affects. Again, based on what I can discern from it.

I have an open request with @High Performance Lubricants to run an AW bench screen on an OTS oil with varying levels of fuel dilution. Dave has been busy, so I'm not going to pester him about it, but when he does have time to have this performed, we'll at least have some additional data.

 

[ZeeOSix]

I agree, but its not a definitive statement driven by test data. Its like me or you saying it. Its in their pre-amble.

How bad? Does it shorten engine life? By how much? How much dilution is too much, etc. We still don't know. This study does not change that. I would actually like to know.

Again, I am not disagreeing with your position on dilution, but said Russian article was presented here as a scientific comprehensive study on the topic, but I don't believe it is. It appears to be a study on measuring dilution, not its affects. Again, based on what I can discern from it.

Agree, and I was just pointing out that the Russian study doesn't address directly the wear with tests and numbers, but they know that too much fuel dilution (like many other studies do), that fuel dilution can be detrimental. They wouldn't make that statement in the Abstract otherwise.

The limit based on some info and links posted in this thread said anywhere between around 2.5 to 5% dilution is the limit before considered excessive and possible increased engine wear/damage. What's Blackstone and other UOA test labs consider the safe fuel dilution limit?

Will have to keep digging for a study that correlates wear rate to fuel dilution percentage with measurements. Could be a pretty involed and expensive experiment using real engines. Maybe the SWRI has done some type of component lab testing in this realm.

 

[BMWTurboDzl]

There is no API, or "Sequence", or any other official oil licensing testing of any kind that addressed fuel dilution that I know of. If someone knows of any, please post up the link(s) to the information. Maybe there should be. Throw that in on top of soot particulate contamination and see what happens.

Perhaps that's because the members of the API don't view fuel dilution as "a problem" that needs to be addressed?

 

[demarpaint]

Perhaps that's because the members of the API don't view fuel dilution as "a problem" that needs to be addressed?

Possibly, maybe because it is more of a long term problem.

 

[ZeeOSix]

Perhaps that's because the members of the API don't view fuel dilution as "a problem" that needs to be addressed?

Most likely they only care about the performance of the oil. They can't determine or control how every engine on the planet is designed and operated. Fuel dilution isn't something that any oil is specifically formulated for. Most engines have acceptable levels of fuel dilution, and for the ones that aren't normal, other measures need to be done to mitigate the negative affects, as shown earlier in this thread.

 

[ZeeOSix]

This paper has a lot of good insight to fuel dilution, and summarizes and references a lot of studies throughout the paper. One thing pointed out in the paper is that gasoline dilution burns off at a much lower temperature (diesel not so much), so engines that routinely get the oil up to full operating temperature and driven for relatively long distances should keep fuel dilution in check, unless there is some major mechanical issue causing the dilution (ie, messed up fueling system, etc). Most here know that, but the paper gets into that somewhat.

This study can be downloaded in PDF for free (download button near the top in the link).

Fuel-Lubricant Interactions: Critical Review of Recent Work

A critical review of recent work on fuel lubricant interactions is undertaken. The work focusses on liquid fuels used in diesel and gasoline vehicles. The amount of fuel that contaminates the lubricant depends on driving conditions, engine design, fuel type, and lubricant type. When fuel...

www.mdpi.com

 

[kschachn]

Most likely they only care about the performance of the oil. They can't determine or control how every engine on the planet is designed and operated. Fuel dilution isn't something that any oil is specifically formulated for. Most engines have acceptable levels of fuel dilution, and for the ones that aren't normal, other measures need to be done to mitigate the negative affects, as shown earlier in this thread.

Correct, fuel dilution is not directly an oil problem, unlike things such as wear, sludge formation, coking resistance, seal compatibility, and even LSPI.

 

[VTECOverRated]

Perhaps that's because the members of the API don't view fuel dilution as "a problem" that needs to be addressed?

Maybe its all a consipracy to better market EV's because "they don't need oil changes" and "maintenance" (lol)

 

[kschachn]

Maybe its all a consipracy to better market EV's because "they don't need oil changes" and "maintenance" (lol)

Probably it’s a misunderstanding of what the API does.

 

[SubieRubyRoo]

I want to get in APIs face before they create the GF-7 tests.

Let's go to a "port fogger" style injector, like the old-school single wet nitrous nozzles were; right behind the throttle body. Dump in all 650HP worth of fuel into the main airflow, and let the port design determine where it goes. Some lean, some fat, but none with dilution. Win some, lose some lol!

 

[SubieRubyRoo]

I have an open request with @High Performance Lubricants to run an AW bench screen on an OTS oil with varying levels of fuel dilution. Dave has been busy, so I'm not going to pester him about it, but when he does have time to have this performed, we'll at least have some additional data.

But which fuel are you using? Top-tier Shell Nitro 93? or bottom of the barrel no-name 87?

 

[dlundblad]

I feel like I can smell gasoline on any gasser’s dipstick so I feel smell is a bad way to measure.

DI engines IMO should get 4k (or so) oil change intervals by default. Heck, change the oil every 4k and the filter every 12k.. something like that.

If you’re worried, you should do a UOA.

 

[Shel_B]

I have an open request with @High Performance Lubricants to run an AW bench screen on an OTS oil with varying levels of fuel dilution. Dave has been busy, so I'm not going to pester him about it, but when he does have time to have this performed, we'll at least have some additional data.

Bless you!

 

[DirectRejection]

Aunt Minnie, you devil, you.

 

[ZeeOSix]

Aunt Minnie, you devil, you.

Don't drive like "Aunt Minnie".

"Bergstra et al. [11] also performed low mileage accumulation tests via frequent cold short trips, which they identified as a particularly severe type of driving pattern, and they referred to these tests as the “Aunt Minnie” driving cycle. After 7000 miles of such driving, fuel dilution levels of 3–5% were found in the summer months and 8–11% in the winter months."

 

[DirectRejection]

But which fuel are you using? Top-tier Shell Nitro 93? or bottom of the barrel no-name 87?

I wonder which high quality fuel is the best option.

Would it be Top Tier Premium or E0 ?

Was high ethanol Chinese fuel a big factor at the beginning ?

 

[ZeeOSix]

I wonder which high quality fuel is the best option.

Would it be Top Tier Premium or E0 ?

From one of the references in the fuel dilution study paper I linked. Fuel dilution with Ethanol fuel has an impact on the AF/AW tribofilm. This paper is also a free PDF download.

Google Scholar

scholar.google.com

 

[VTECOverRated]

I wonder which high quality fuel is the best option.

Would it be Top Tier Premium or E0 ?

Was high ethanol Chinese fuel a big factor at the beginning ?

I run Shell 93 V power in my turbo cars. The reason being, mostly, is it I get the lowest amount of ignition pull and timing pull back with their gas (as per data logs). I am running a stage 3 tune from Pherable though on the Accord and their 1.5 GOD tune on the Civic.

On the camry I use whatever 87 octane there is, usually sams club because its a solid 10-15 cents cheaper than everyone else. It has ran flawlessly for 250k+ miles. Every 15-20k miles I would run a fuel injector cleaner. I tried running 93 V power on a long trim to Florida and I gained precisely...0.1 MPG average with an overall average of 42.3 MPG. (this is running v power on the way back, and ****ty 87 on the way there). On naturally aspirated motors....there is quite literally, zero difference in my experience. If you are worried about deposits and stuff, just use a fuel additive like lucas which has been tested to work just fine.

 

[kschachn]

I run Shell 93 V power in my turbo cars. The reason being, mostly, is it I get the lowest amount of ignition pull and timing pull back with their gas (as per data logs). I am running a stage 3 tune from Pherable though on the Accord and their 1.5 GOD tune on the Civic.

On the camry I use whatever 87 octane there is, usually sams club because its a solid 10-15 cents cheaper than everyone else. It has ran flawlessly for 250k+ miles. Every 15-20k miles I would run a fuel injector cleaner. I tried running 93 V power on a long trim to Florida and I gained precisely...0.1 MPG average with an overall average of 42.3 MPG. (this is running v power on the way back, and ****ty 87 on the way there). On naturally aspirated motors....there is quite literally, zero difference in my experience. If you are worried about deposits and stuff, just use a fuel additive like lucas which has been tested to work just fine.

Precisely 0.1 MPG? And you were able to conclusively attribute that to the octane rating of the fuel?

Amazing.