2018 WRX Pennzoil ultra platinum 5W30 - 3050 miles

The amount of sheer misinformation and Internet lore that revolves around what an octane rating means and what it does not mean is incredible. In and of itself the octane rating does not affect flammability, speed of burn, nor temperature of burn. It does not affect how the fuel "burns off", nor does it affect the BTU content of the gasoline by itself.

Just to start.
 
When I think of flammability I think of it quite literally, as the propensity to ignite when exposed to an open flame. This is why I take issue with its use with respect to comparing octane ratings since, for all intents and purposes, regardless of the fuel's resistance to auto ignition (what the octane number represents) they are all equally inclined to ignite when their vapours are in the presence of an open flame.

flam·ma·ble
[ˈflaməb(ə)l]

  • easily set on fire

As you see the definition of Flammable doesn't limit to just an Open Flame as you say.
 
The fuel octane rating affects the ability to resist pressure ignition which is different than flammability.

You're saying that 93 octane's ability to resist pressure ignition can't be stated by simple terms of "less flammable". aka "It doesn't pass the smell test". 😅

If that's the case how do you two easily convey this important work to the regular joe/jane in regular understandable lingo?
 
I'm not sure why you need to do so. Regular Joe and Jane should be observing the minimum octane rating listed on the fuel door or in the owner's manual, otherwise suffer the consequences. If the engine still knocks then a mechanical issue might be suspected.
 
flam·ma·ble
[ˈflaməb(ə)l]

  • easily set on fire

As you see the definition of Flammable doesn't limit to just an Open Flame as you say.
I think we all know how to use a dictionary.

Did you look at the etymology section?
- Latin flammare to flame, set on fire, from flamma

If we look at the WIki entry:
A flammable material is something that can burn (i.e., sustain a flame) in air under certain conditions. A flammable material is flammable if it ignites easily at ambient temperatures. In other words, a combustible material ignites with some effort and a flammable material catches fire immediately on exposure to flame.

So while being flammable does not preclude something from being set alight by means other than open flame, the genesis of the word is based on that concept.
 
Got it... Never use the word "Flammable" or "Non Flammable" when discussing octane or you two will have a word with me. :p

I'm off to go set at the kiddie table now...
 
Just got my first UOA results back for this car. I’ve been changing the oil every 3000 miles to be safe until I was able to do a UOA. At this point with the fuel dilution I’m thinking I shouldn’t go past 3,000 miles.

2018 WRX 2.0 FADIT - Direct injection
CVT

I am not super familiar with all the other numbers. I was mostly concerned with the fuel dilution. If some doesn’t mind letting me know how every thing else looks I’d appreciate it!

This car is my work commuter. It has never seen a short trip since I’ve had it. It does not idle more 5 minutes a day. I park it in my heated garage, and only let it idle leaving work until it comes off high idle. I set my cruise control at 70-73. Does not see any type of excess acceleration or anything like that. My work commute is 35 miles each way. So 70 miles per day with less than 5 miles of that being non highway.

The interesting thing I’ve noticed is the oil temp very rarely gets over 200 degrees. I’m wondering if the temp not getting over 200 is not allowing the fuel to burn off/evaporate. Not sure what to think about the oil temp.

Thanks in advance guys
Different strokes. The report is fine, except for the fuel. The oil, your drive, and your driving style is fine. I think you're right to change the oil at 3 to 4 thousand miles. The temp is what it is, just put it in D and enjoy your day. 02.
 
Thanks for all the info on octane. I try to use top tier 93. If I have to settle for non top tier I will add a bottle of octane booster. I always keep one bottle in the car just in case.

Should I consider using a different viscosity oil? Maybe a 5W40?

I really had my heart set on running HPL, and going 6,000 miles to try and recoup some of the cost. But at this rate of fuel dilution I can’t go more 3-4,000 miles and the cost of HPL would be excessive.

Thanks everyone!
 
Thanks for all the info on octane. I try to use top tier 93. If I have to settle for non top tier I will add a bottle of octane booster. I always keep one bottle in the car just in case.

Should I consider using a different viscosity oil? Maybe a 5W40?

I really had my heart set on running HPL, and going 6,000 miles to try and recoup some of the cost. But at this rate of fuel dilution I can’t go more 3-4,000 miles and the cost of HPL would be excessive.

Thanks everyone!
Hey bud. Had a 16 wrx 6 speed. I'm up in New Hampshire. I always used a 40 grade oil and my Temps were around 210* regardless of temperature outside during normal driving. Granted they hit 230+*, however I was doing Kancamagus runs. I used to run 5k changes no problem, but you have to get on it to heat that oil up.

Idk if you monitor your dam or knock retard, however when she pulls timing, it's going to keep it pulled until you get on it a few times and it raises your dam to 1.000. Running with retarded timing will lead to more fuel getting into that pan.

And for the love of God, do not use anything but 93 in that car. You don't want to give those weak ass rods any reason to exit stage left and pull a no call no show.
 
Thanks for all the info on octane. I try to use top tier 93. If I have to settle for non top tier I will add a bottle of octane booster. I always keep one bottle in the car just in case.

Should I consider using a different viscosity oil? Maybe a 5W40?

I really had my heart set on running HPL, and going 6,000 miles to try and recoup some of the cost. But at this rate of fuel dilution I can’t go more 3-4,000 miles and the cost of HPL would be excessive.

Thanks everyone!
5w-40 seems too thick. The exit viscosity on the 5-30 was 8.7 which is thick, enough, to keep the parts separated and better on cold starts. .02.
 
I have the same fuel dilution issue with my '22 Crosstrek with the non turbo 2.0 GDI engine. Fuel dilution definitely increased almost 2% in the colder winter months here in the PNW. I change my oil every 3,000mi because of the dilution and I'm going to try Mobil 1 ESP 0W-30 next oil change. Last UOA showed my highest GC fuel dilution yet at 3.1% in 2774mi. Yours is quite a bit higher and you definitely do more highway driving than we do. 🤷‍♂️ Interesting....
 
Should I consider using a different viscosity oil? Maybe a 5W40?

I really had my heart set on running HPL, and going 6,000 miles to try and recoup some of the cost. But at this rate of fuel dilution I can’t go more 3-4,000 miles and the cost of HPL would be excessive.
Do some research on Pennzoil Platinum Euro L 5W30. It is very thick for a 30 grade (11.9 cSt), holds its viscosity well, excellent cold weather properties, lots of stringent Euro certifications and $26.50 for 5 qts at Walmart.

VOA:
https://bobistheoilguy.com/forums/threads/pp-euro-l-5w30-voa.361111/

A couple of UOAs:


Other oils that have been recommended for high fuel dilution are

M1 ESP 0W30: https://bobistheoilguy.com/forums/threads/voa-mobil-1-esp-0w-30.365257/post-6385231

and 5W30: https://bobistheoilguy.com/forums/threads/mobil-1-esp-5w30-voa.361030/

The two M1s are also Euro oils and can be bought from AutoZone in 5qt jugs for around $37.

The idea being these three oils start off thick and have more ability to retain viscosity and protection when dilution is a factor.
 
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@OVERKILL
@fantastic
@kschachn

I’m not trying to get another quick smack on this horse (well… maybe I am) but why stress so much over SIX (6) octane points out of almost 100? I find it silly.

If we were comparing diesel fuel (40’s) vs race fuel (115’s) I can understand as there’s a WIDE SPREAD of 75 between the two and arguments can be made which is more resistant to detonation (flammable? 😏🤭😜) easily but we are talking about 6 octane points between “regular” and PREMIUM 😂🤣😆🤪
 
@OVERKILL
@fantastic
@kschachn

I’m not trying to get another quick smack on this horse (well… maybe I am) but why stress so much over SIX (6) octane points out of almost 100? I find it silly.

If we were comparing diesel fuel (40’s) vs race fuel (115’s) I can understand as there’s a WIDE SPREAD of 75 between the two and arguments can be made which is more resistant to detonation (flammable? 😏🤭😜) easily but we are talking about 6 octane points between “regular” and PREMIUM 😂🤣😆🤪
 
@OVERKILL
@fantastic
@kschachn

I’m not trying to get another quick smack on this horse (well… maybe I am) but why stress so much over SIX (6) octane points out of almost 100? I find it silly.

If we were comparing diesel fuel (40’s) vs race fuel (115’s) I can understand as there’s a WIDE SPREAD of 75 between the two and arguments can be made which is more resistant to detonation (flammable? 😏🤭😜) easily but we are talking about 6 octane points between “regular” and PREMIUM 😂🤣😆🤪
HA! I was actually going to return to this thread & ask if it was ok to say those 2 dirty words when comparing Diesel vs Gasoline. You read my mind. 🤣
 
One thing we are discounting here is the driving patterns/habits of both of these gentlemen. They drive.....ummm....very safely, let's say that.

Nothing wrong with that. However, couple that with the ecu logic, you have the recipe for fuel in the oil pan.

Listen, many of times when you start these cars on stock tunes, the DAM almost always starts at .667. That means your timing is retarded as hell. That DAM will only go up if it sees higher loads with no adverse timing events.

Let the oil get up to 160+, then don't be afraid to get on it a bit from 3500rpm and up. I'm not talking about fully booting it or driving like a complete hotboi, just give it a little some some.

The more I drove my a little harder, the less fuel I had in my oil.

I have driven my from stock to near 400whp using these habits. I've had less fuel in my oil under both circumstances.
 
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These engines just put some fuel in the oil and it is what it is. I'd wager that if you went to 5K you'd see similar fuel% numbers. Highway driving is about as good as you get for this issue vs. short trips around town. The viscosity doesn't look like it dropped that badly to me vs. what it likely started at. What does Subaru recommend in terms of OCI? 3K is just so short if you are a highway commuter but clearly you have some basis for keeping the short OCI. Some may recommend going with a 40W and stretching out the OCI a bit more as the ending viscosity will be higher than what you started with here including the drop due to the fuel.

The 87 vs. 93 w/r to how this impacts dilution and burn off is beyond words.
 
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