AAA Conventional vs Synthetic Oil Study

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363
Location
Boise, Idaho
We keep hearing how good so many conventional are these days. I have been changing oil in my cars for 40 odd years. Oils have gotten better and better. I hear about cars that even if you use synthetics the manufacturer still wants the oil changed sooner than many synthetics claim you can run it. I think I have such a car. Nissan wants me to change the oil at 3750 miles and does not specify conventional or synthetic. The spec is use API SN oil. Just change it at 3750 miles if driven in the conditions that we do drive it in. Lots of stop and go in the city. Well I don't put any expensive synthetics in it. I have, but realized I can get the same bang for my buck using high quality conventional or blends. Right now it has Chevron supreme 5w30.
 
Originally Posted By: Dyusik
Originally Posted By: TexasVaquero
Buy Synthetic if you want to keep your car for more than 3-4 years. I bet those guys at Blackstone just get new cars because they got the means. For us normal folk that want to keep our cars for longer periods, Synthetic.
My old Beretta didn't see synthetic oil f2f or over 25 years. I see a lot of heaps and classics driven by people that don't use syn oil. That blanket statement was as confused as it is untrue.
+1 , Older low tech engines get by just fine on Dino oils provided they have a good concentration of ZDDP and such. A modern Ecoboost engine though? then yes, by all means use a full synthetic oil.
 
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1,365
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Europe
It might be worth mentioning that the original, frankly not-very-good, Group I-based so-called Dino oils, became extinct in the US around 20 years ago. What Americans call Dino oils today are either all Group II or Group II with a trim of Group II+ or Group III. Unlike their Group I counterparts, these base oils have been hydrocracked, catalytically dewaxed and very likely hydro-finished. This means that in terms of their resistance to oxidation, sludge formation, etc, the oils are far closer to being synthetics than they are to the Group I based oils from which the 'Dino' moniker derives. You can probably add to that that overall additive contents (ZDDP reductions notwithstanding) are roughly double what they were two decades ago. If it wasn't for the fact that 'the system' forces US oils to far more volatile than they need to be (something that affects both conventional and synthetic alike), I'd be shouting their merits from the rooftops.
 
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1,462
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CA
I found this part as interesting as the study itself: Secondary Research Oil companies have evaluated the performance of conventional and synthetic engine oils by sampling used engine oils from real-world vehicles. AAA reviewed published research in this area to understand real-world performance. In one study, a matrix of almost 500 used oil samples were obtained from vehicles operating in and around Houston, Texas. One hundred and twenty of the nearly 500 samples were formulated using full synthetic base stocks. Within the samples, numerous brands and additive chemistries were represented. A rapid decrease in oxidation resistance occurred in mineral-based engine oils after 3,000 to 4,000 miles of use. In some cases, very low oxidation resistance was found after 2,000 miles of use. Significantly better results were observed for synthetic based lubricants. The authors did not attempt to attribute this to the better stability of the synthetic base stock or the specific additive package. It was also found that synthetic-based engine oils retain the ability to neutralize acids appreciably longer than mineral-based engine oils. It was concluded that many of the better performing engine oils subjected to real-world use were formulated using synthetic base stocks
 
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3,292
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BC, Canada
"The system forces US oils to be far more volatile than they need to be". Sonofjoe, is that a result of 0W & 5W winter grades attached to OEM approved engine oil for ambient -40C to 50C? If so, chasing VI and one grade for all climate conditions is incorrect.
 
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1,365
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Europe
Originally Posted By: CharlieBauer
I found this as interesting as the study itself: Secondary Research Oil companies have evaluated the performance of conventional and synthetic engine oils by sampling used engine oils from real-world vehicles. AAA reviewed published research in this area to understand real-world performance. In one study, a matrix of almost 500 used oil samples were obtained from vehicles operating in and around Houston, Texas. One hundred and twenty of the nearly 500 samples were formulated using full synthetic base stocks. Within the samples, numerous brands and additive chemistries were represented. A rapid decrease in oxidation resistance occurred in mineral-based engine oils after 3,000 to 4,000 miles of use. In some cases, very low oxidation resistance was found after 2,000 miles of use. Significantly better results were observed for synthetic based lubricants. The authors did not attempt to attribute this to the better stability of the synthetic base stock or the specific additive package. It was also found that synthetic-based engine oils retain the ability to neutralize acids appreciably longer than mineral-based engine oils. It was concluded that many of the better performing engine oils subjected to real-world use were formulated using synthetic base stocks
One needs to exercise a bit of caution in interpreting this kind of thing as often as not, the collectors of the original data aren't impartial bystanders and have their own agenda to push (like encouraging you to buy more profitable synthetic over less profitable conventional). Yes, it's highly likely that after 4k, a conventional oil will 'have less resistance to oxidation than a synthetic' but that's not the same as saying it has NO remaining resistance to oxidation. The same goes for TBN. Oxidation per se isn't actually a problem until things reach a tipping point, at which manifestly bad things occur. This usually happens all at once when the oil's viscosity goes through the roof, highly condensed/polymerised gunk drops out of solution as sludge and so much acidic stuff is floating around oil that bearing metal starts disappearing at a rapid rate of knots. At a very rough guess, I'd say most conventional US oils wouldn't reach this truly bad situation until you go beyond 12k miles. And yes, synthetics will very likely not reach this point until much later (I took one of my own synthetics out until 15.5k and it was fine) but the reality is that almost no-one in the US extends their OCI this far. So where is the true benefit?? If I put it another way, at 61 years old, I have 'less resistance to death' than I once did. However that doesn't mean I'm in imminent danger of falling off my perch tomorrow and another 10 - 20 years might be quite doable!
 
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Originally Posted By: userfriendly
"The system forces US oils to be far more volatile than they need to be". Sonofjoe, is that a result of 0W & 5W winter grades attached to OEM approved engine oil for ambient -40C to 50C? If so, chasing VI and one grade for all climate conditions is incorrect.
The main reason for this is the crazy way ILSAC has organised it's fuel economy tests. If memory serves, a US 5W30 has to have demonstrably better fuel economy than a 5W30 reference oil. Yes, you read it right. It says something must be better than itself!! No doubt this particular piece of madness was done in the name of 'simulating innovation'. The reality is that most US 5W30s have simply been formulated such that they are halfway to being 0W30s (by dropping the CCS, you drop the KV between 0 and 100°C which translates to a fuel economy credit). For any base oil group, to drop the CCS, you need to lighten the base oil mix making the oil more volatile. If you lighten the base oil mix, you need to add more VII polymer, If you add more VII, you need to lighten the base oil mix a bit more. As often as not, if you add more VII, you need to add a bit more Ashless Dispersant to maintain piston cleanliness. Ashless kills your CCS so you need to lighten up the base oil mix again and the cycle keeps going round and round until you reach equilibrium, but what you always end up with is a oil that is far more volatile than it needs to be. It's probably also worth mentioning that once you take that first misguided step to say a 5W30 must be better than a 5W30, the impact cascades to all of the other grades, both heavier and lighter.
 
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3,292
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BC, Canada
I've noticed a trend with HDEOs, that if it wasn't for CCS, it would pass the next W grade lower especially with synthetic blends. For example, a 10W30 passes 5W and almost passes the 0W pumping and flow requirement, but the CCS is 10W.
 
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1,777
Location
Pennsylvania
Originally Posted By: Panzerman
I use synthetics simply because I get good deals on synthetic oils on clearance, rebates etc.. If I was to have to buy all my oil for retail price and the prices they state are what auto stores sell thier oil for, I d probably go with Conventional oil. What I don't get is all the oils meet SN API standards so really how much better is synthetic than Conventional if they both meet the same API. Changing your oil at reasonable intervals is more important than oil type. 6 months or 6000 miles Max and use whatever is cheaper. I never understood the crowd that pays three times as much for Amsoil to run it three times as long. Makes no sense to me but then I change my own oil and usually 4000 to 5000 miles too. Anymore and I have anxiety.
Same here, I'm stocked with both Pennzoil Platinum and Valvoline Synpower that cost less than $10 per jug.
 
One needs to exercise a bit of caution in interpreting this kind of thing as often as not, the collectors of the original data aren't impartial bystanders and have their own agenda to push (like encouraging you to buy more profitable synthetic over less profitable conventional). Couldn't agree more. After I read the report the first thing that came to mind is why go to the expense? Do they have a dog in the fight; what's their agenda? Well, after 15 seconds of research I discovered Triple "A" has their own "Car Care Centre's" that provide oil change service. Hardly unbiased. In the TEOST-MHT deposit test two of the conventionals are absolute dogs that skew the results. The other three are actually better than the synthetics. Given the number of PCMO's sold in the U.S. I would guess it wasn't too hard to find a couple of suspect oils sold nationally. I highly doubt any of the majors would fail so miserably on this test. 0w20 not 5w20 is now the more recommended synthetic oil with new N.A. vehicles (most certainly with Japanese). 5w20 dino might be recommended as their oil of last resort. Therefore, that comparison would be more apropos. There's two possible reasons why this wasn't done: 1) 0w20 oils are exempt from the TEOST-33C test - concession to the Japanese love affair with molybdenum - because of its failure rate; 2) 0w20 oils NOACK average is JUST below 13 to meet dexos 1 certification as shown on PQIA's web site. I change my oil every 5000 to 7000 KM's depending on the weather. I highly doubt any synthetic in the XW-20 flavour would beat my El-Cheapo 10W-30 dino for my vehicle.
 
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Messages
3,236
Location
Phoenix, Arizona - USA
Originally Posted By: TexasVaquero
Buy Synthetic if you want to keep your car for more than 3-4 years. I bet those guys at Blackstone just get new cars because they got the means. For us normal folk that want to keep our cars for longer periods, Synthetic.
Ugh.. really? What a misguided thing to say. The Fusion in my sig - my daily driver - sees over 500 miles per week, in Phoenix, and rarely gets an OCI shorter than 7,500 miles. I've run anything from straight dino to full PUP synth, and everything in between, depending on what I have on hand, what season it is, etc... Right now, it's got a mix of Valvoline NextGen conventional 5w20 and MaxLife 5w30 in it, but I've done multiple 7,500 miles OCIs running pure dino. ... I guess the 232,000 miles I have on it is just a fluke? I plan to keep the car up to at least 350,000 miles, and have a goal of just under 484,000 miles.. and I don't plan on doing anything different as far as oils/OCI goes. It will still see plenty of 7,500 mile OCIs on straight Dino.
 
Originally Posted By: TexasVaquero
Buy Synthetic if you want to keep your car for more than 3-4 years. I bet those guys at Blackstone just get new cars because they got the means. For us normal folk that want to keep our cars for longer periods, Synthetic.
Then explain this: I had a brand new '93 Honda Civic which I kept for ~6 years then gave to my sister. She kept it for a few more so I wouldn't be surprised if there was close to 250,000 KM on the ODO. All this was done with 5w/10-30 dino juice (me anyway). If all PCMO's are so much superior now as opposed to then, then how was that possible? "All that glitters is not gold"
 
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385
Location
Fly-over country
Originally Posted By: ndfergy
One needs to exercise a bit of caution in interpreting this kind of thing as often as not, the collectors of the original data aren't impartial bystanders and have their own agenda to push (like encouraging you to buy more profitable synthetic over less profitable conventional). Couldn't agree more. After I read the report the first thing that came to mind is why go to the expense? Do they have a dog in the fight; what's their agenda? Well, after 15 seconds of research I discovered Triple "A" has their own "Car Care Centre's" that provide oil change service. Hardly unbiased. In the TEOST-MHT deposit test two of the conventionals are absolute dogs that skew the results. The other three are actually better than the synthetics. Given the number of PCMO's sold in the U.S. I would guess it wasn't too hard to find a couple of suspect oils sold nationally. I highly doubt any of the majors would fail so miserably on this test. 0w20 not 5w20 is now the more recommended synthetic oil with new N.A. vehicles (most certainly with Japanese). 5w20 dino might be recommended as their oil of last resort. Therefore, that comparison would be more apropos. There's two possible reasons why this wasn't done: 1) 0w20 oils are exempt from the TEOST-33C test - concession to the Japanese love affair with molybdenum - because of its failure rate; 2) 0w20 oils NOACK average is JUST below 13 to meet dexos 1 certification as shown on PQIA's web site. I change my oil every 5000 to 7000 KM's depending on the weather. I highly doubt any synthetic in the XW-20 flavour would beat my El-Cheapo 10W-30 dino for my vehicle.
+1. Well said. It's easy to overlook that if one had selected one of the better performing conventional oils that it could very well outperform a significantly more expensive synthetic oil.
 
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1,365
Location
Europe
Just a random thought but if you do like synthetic, it might be wise to stock upon it while there's plenty on the shelves. Why? Well that insignificant dot on the map called Qatar has managed to seriously upset it's neighbours and it seems they're closing transport links to & from Qatar. Now Qatar just happens to be where Shell's HUGE GTL plant it located. If for whatever reason (a seaward blockade maybe?), the plant had to be turned off for any length of time, then the effect on global Group III base stock supply would be felt very quickly indeed. There's not a lot of spare Group III capacity that could be brought online to back fill the shortage so I'm guessing prices might rise. Just idle speculation on my part but it might be worth bearing in mind...
 
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Messages
245
Location
Georgia, USA
Originally Posted By: Shannow
Originally Posted By: Artem
The only proof I've ever needed on the synthetic vs Dino oil was the frozen pour test done many many years ago (you can find a bunch on YouTube) where Synthetic CLEARLY pours quicker and better then conventional. <-- that's all I need to know. popcorn
In florida ????
Yeah, it gets cold in florida . . . 50 degrees (F) is cold (to them)
 
Messages
806
Location
Denver
Synthetic VS Conventional debate. I know little about the formulation of motor oil. I do know that I feel much better with full synthetic in my cars when: 1-I'm sitting in rush hour traffic on I-70 and my dash board is telling me its 110 degrees in August sitting on the asphalt. 2-It is 20 below zero when I start my car in January.
 
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17,301
Location
OH
Would it be fair to say that you mean that we should just say no to ILSAC oils? You make a compelling case for avoiding them and it can certainly be done.
 
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