Traditional oil vs. synthetic.. any opinions?

<div class='quotetop'>QUOTE(dylandog @ Jan 28 2007, 11:36 AM) [snapback]381979[/snapback]</div>

For years I've been looking for a comprehensive analysis indicating , or at least empirical evidence stating, that synthetic oil is better than regular oil for gas mileage or engine longevity. I don't see any other potential benefit. I have yet to see any evidence. For something that is so wonderful and obvious to so many people, you'd think there would be a large number of studies to prove this. My observation is that this is less an engineering study than a religious one. Maybe people unconsciously like the smell of the additives in synthetic better?

Oil is a collection of hydrocarbon chains. The shorter the chains, the lighter the oil. How a synthetic HC=CH bond could be "better" than a naturally occurring one is beyond me. A bond is a bond. Bonds break under high temperatures and pressures regardless of how the bond is created.

There are some vehicle specs that require synthetic in some applications, and the only reason I could think why is because the range of HC chain lengths, and therefore viscosities in the mix, could be more tightly controlled with synthetic. Perhaps there are conditions where a very tightly controlled viscosity range helps, but still, no information.

If you find evidence, please let me know.

Until then, synthetic in general has to go into the drawer with nitrogen in tires, and stiffening plates.

 

<div class='quotetop'>QUOTE(Display Name @ Jan 28 2007, 11:00 AM) [snapback]381993[/snapback]</div>

I don't think that you have done a very good job looking at the evidence...

Synthetic oils are indeed superior to regular oils in at least one area - they don't break down as easily under heat and pressure. They also are superior in friction reduction. They are a lot more expensive to manufacture and consequently are not used as often. There are a number of high end vehicles which do specify synthetic oil - Porsche for example. Some motorcycles also use them on newer bikes (I use it in my BMW motorcycle).

In general aviation, use of semi-synthetic oils (blend of regular oil and synthetic) is normal. In general aviation, mineral oil is used initially for engine break-in as it allows the rings to seat properly against the cylinder walls. After the initial break-in period, the oil is replaced with semi-synthetic. (People who own these airplanes have a tendency to very carefully maintain the engines as it typically costs $ 15,000 - $40,000 to rebuild an aircraft engine after 1,800 - 2,000 hours. I know this as a fact - as a pilot and aircraft owner for many years who has had to burden the cost of maintaining an aircraft (including rebuilding an engine).

When it comes to automobiles, most people only keep an automobile for less than 5 years. Consequently it does not make sense to use synthetic oil which will extend the life of the engine. Detroit is in the business of of selling new cars to people on a regular basis. Why would they want to encourage people to take good care of their automobiles and keep them longer???

If you plan to keep an automobile for a long time, using synthetic or semi-synthetic oil is a reasonable insurance policy.....

Regards,

Keith

 

<div class='quotetop'>QUOTE(Display Name @ Jan 28 2007, 11:00 AM) [snapback]381993[/snapback]</div>

What the Tech Guy said is right on. It's not hokey like the nitrogen thing.

Mobil has a web site that explains the difference and the benefits. www.mobiloil.com

It even describes a taxicab test in Las Vegas, where they had 5 Prius' as part of the test.

In summary, they emphasize better engine protection and longer intervals between changes. They hint at better fuel efficiency - but do not claim it as a primary benefit.

 

My take: Synthetic will extend the life of the engine, but the cost for the synthetic oil won't be recovered in lowered maintenance.

If your goal is to enable the engine to outlast the rest of the car, synthetic is a good choice. If you are the kind of person who is excessively inconvenienced by engine failures, then maybe synthetic oil is good insurance for you.

As for me, I'm trying to live on a low budget right now, and synthetic simply costs too much for what I get. I used to use synthetic exclusively when I had more money to spend. Partly because my obsessive side likes treating my car as well as I can. And partly because it does increase reliability by some small amount.

 

<div class='quotetop'>QUOTE(Tech_Guy @ Jan 28 2007, 01:01 PM) [snapback]382007[/snapback]</div>

This is the problem, everyone invariably responds with "well then you haven't paid attention to the evidence", then they rattle off the same benefits, with no evidence.

I've searched the web, posted on numerous gear-head and propeller-head web boards, no such evidence is ever forthcoming.

Mind you, all I want to see is a side-by-side comparison of two identical cars, one using regular oil, one using synthetic over the lifetime of the cars. Synthetic should have better gas mileage and fewer mechanical problems with the engine right?

For as wonderful as synthetic is purported to be, you'd think there'd be all sorts of comparative data.

I have an open mind to this, if there truly is evidence it's better, then I'm obligated to agree.

 

<div class='quotetop'>QUOTE(John in LB @ Jan 28 2007, 01:43 PM) [snapback]382012[/snapback]</div>

Been there also, revisted recently in case they started posting data.

You're right, they emphasize how much better the engine protection is, but without any measurements to back it up. Longer intervals determined how?

What I see are photos of parts that are said to be such and such with no measurements.
Lot of impressive rhetoric such as:

<div align="center">
"In general, fully synthetic motor oils contain non-conventional, high-performance fluids. Synthetic Blends usually use some non-conventional, high-performance fluids in combination with conventional oil. To meet the demanding requirements of today's specifications (and our customers' expectations), Mobil 1 with SuperSyn Technology and Mobil 1 Extended Performance with its Advanced SuperSyn System, use high-performance, engineered fluids, such as polyalphaolefins (PAOs), along with a proprietary system of additives."
</div>

Sure sounds good.

I can't see video on a dialup, but I see no performance comparisons. If I'm clicking past the data in error, please post direct url.

A really simple test would be measuring viscosity of regular and synthetic oils over the course of one oil change period. A relatively simple one would be using two brand new engines, take photo-micrographs of wear surfaces on both, run both for equivalent of X miles, then measure the wear. To have both done by an independent lab (important) would be the holy grail, and then I'd start buying synthetic and pushing it on everyone.

What I see here is what I see everywhere "we tested it extensively, and it was wonderful!"

In the end, I'd be happy to have a polymer chemist (as opposed to a salesman) explain how a regular hydrocarbon chain is any different than a synthetic hydrocarbon chain.

Here's why I think it's more religion than engineering. My expecting scientific proof offends people who love synthetic because it's an affront to what they believe in. It's like telling a Catholic that God doesn't exist, it tends to be offensive. On the other hand, it's reasonable to expect that something claimed to be so good, should have proof.

People have gotten 250-500k miles out of engines long before synthetic came on the scene. (Not that many cars can actually do that anymore...)

 

<div class='quotetop'>QUOTE(dylandog @ Jan 28 2007, 10:36 AM) [snapback]381979[/snapback]</div>

I use synthetic, but it's really up to you. Probably not really necessary if you change at 5K miles. The dealers sell synthetic oil, which will work in a Prius. I generally bring in my own oil and that's deducted from the bill.

 

The first hit on Google for "Synthetic oil" brings up a study for gearheads.

If you dig deeper, there's one for normal people, too.

Conclusion: Synthetic is better. Unless you're flying a jet.

 

<div class='quotetop'>QUOTE(Display Name @ Jan 28 2007, 07:33 PM) [snapback]382140[/snapback]</div>

I am sorry, but I am not going to do the research to provide you absolute proof. I have satisfied myself to a reasonable degree that it is a legitimate product and not just snake oil. There are enough legitimate companies and engineering awards given to this product to indicate that it is superior to normal oil.

To what degree it is a better product and does it pay out... I can't tell you. For me, I put a lot of miles per month on the car and I use Mobil 1 to extend my change interval from 5000 miles to 10000 miles so that I don't have to do the service except every 5 months or so (instead of every couple of months). I do the oil change myself, so the end result is that it costs me about the same as a regular oil change of every 5000 miles.

I can say that I have noted a slight improvement in my gas mileage (~ 1 MPG), but that's anectodal and I figure it is gravy if I am actually getting that benefit.

One thing that we do not discuss on this forum as a benefit: It is a significant environmental plus in that I only consume half the oil that others use - that means less recycling and waste.

 

Synthetic oils have been around for decades and their record speaks for themselves as proof they do work as advertised. But if you are still under warranty then you still want to change the oil per the owners manual to keep it valid. After that you could safely go 10,000 miles between oil changes. If you worry about dirt then change out the oil filter sooner. But the oil can handle the mileage safely.

 

<div class='quotetop'>QUOTE(dylandog @ Jan 28 2007, 01:36 PM) [snapback]381979[/snapback]</div>

Usually they are. The oil is easy to change in a Prius, so why not do it yourself?

Yes. A big benefit that hasn't been mentioned is that full synthetic will never sludge up inside a motor. Conventional oil will, especially if oil change intervals are extended by a large amount. Dealers all have horror stories of people who pay $$$ for a new vehicle, then never change the oil. Massive amounts of sludge form, block passages and causing motor failures.

Of course they are. Synthetic oils are good in any modern vehicle

Synthetics resist breakdown better and resist sludging much better than conventional oil. Synthetics protect better, and also give a slight edge in fuel economy. Synthetics cost more.

Harry

 

I'm also coming up on my first oil change and will use synthetic. I started using Mobil 1 when it came out about 30 years ago and have used it exclusively. About 12 yrs ago we had a horrendous cold spell, and our 2 Sentras were the only cars able to start in my apartment complex, without any problems.

 

I know this isn't a scientific test but I once put synthetic in a honda 750 motorcycle that used a wet clutch. After doing this my clutch slipped all the time.

In my mind this ment that the synthetic caused less friction in the clutch plates. Which to me means less friction between moving parts of the engine.

 

I think what the OP is asking for is basically this:

Dino oil = blend of alkanes/cycloalkanes (aka "paraffins") of various configurations of approximately the same molecular weight that comes out of the fractionating tower, blended with polymers, viscosity modifiers and other additives. Many of the "synthetic" brands on the market are actually just better refined alkane-based oil that has gone through additional hydrocracking and other processes such that at the end, you get a higher fraction of identical molecules that are all of the same size and shape (vs. the random blend of stuff that is around the same weight in "regular" oil). This stuff is also referred to as "isomerized" oil- ie made all the same and based on API "group III" base stock.

"true" synthetics = blends of compounds that are not found in any significant proportion in dino oil and of significantly different chemistry (ie, not alkanes/cycloalkanes). The two primary types of synthetic compounds used for lubricating purposes are PAO (polyalphaolefin) (API "group IV") and synthetic ester (group V) compounds..

Because "synthetic oils" are based on completely different compounds (PAO and esters vs. alkanes/cycloalkanes), they will have different behaviours inside your engine.. Again, regular oils are paraffins, in other words, they are just lighter, more liquid grades of "candle wax".. What happens to candle wax when it gets hot? Well, it gets thinner, starts to smoke and then burns very readily. Paraffins are also easily attacked by many solvents (such as in gasoline) and become thinned and more volatile.. Lets compare to a synthetic: PAOs in particular tend to be very low friction compounds (polyethylene is an example of a common PAO; it's not a liquid at room temperature, but it does exhibit many of the same properties: PE is very slick and low friction and requires special primers and handling procedures to bond, it is immune to most forms of chemical attack and is used to store many laboratory solvents, ie, on it's own, it's already a very good material, and in fact, by adding fluorine, you make PTFE, which is more commonly known as Teflon, which is one of the slickest, and lowest friction materials known to man). PAOs in general are also more resistant to heat and solvent attack and when used in an engine, provide improved lubrication properties as well as longer life.

Here's the real crux of the matter: regular dino oils are perfectly sufficient for *all* the needs of a vehicle engine (ie, although synthetics are better lubricants, the engine simply doesn't need anything better- the additional lubricity *may* translate into some additional fuel mileage, but that's more dependent on the driver than anything else) *AS LONG AS YOU CHANGE THE OIL BEFORE IT DEGRADES*: before too much of it burns off or is thinned by contact with heat and fuel, and before it collects too much contamination.. So while you may get some additional benefits due to the improved lubricant properties, really, the major benefit of synthetic oils is in extending the interval between required changes due to their improved resistance to breakdown- this extended interval is well documented in all the various oil analysis reports that thousands upon thousands of vehicle owners have had done and made available (including some here on PriusChat)..

 

<div class='quotetop'>QUOTE(c4 @ Jan 29 2007, 08:53 AM) [snapback]382297[/snapback]</div>

AMEN! (Thank G-d for Hydrocrackers and FCC units!!! Oh, yeah, and the old dewax plant too...

 

<div class='quotetop'>QUOTE(c4 @ Jan 29 2007, 11:53 AM) [snapback]382297[/snapback]</div>

Indeed. From what I've read it seems the benefit for most cars that have their oil changed regularly at relatively short intervals is pretty minimal. That said, I don't think it's bad practice to use synthetics in place of regular oil for those oil changes. I just question the logic by some people who while saying that synthetics are better (and they are), just turn around and extend their oil change interval to twice as long, since that basically just means the bulk of the benefit from synthetics is lost. I do suppose there could be some cost saving there though. Personally, if I were using synthetics, I'd consider extending the interval between oil changes, but not by twice as much. Mind you, that's just me though.

P.S. Sort of off topic but hey...

Many years ago, a friend of mine asked me how much she should sell her 10 year-old VW Rabbit for. I asked her a bunch of questions, including how religiously she maintained her car, like with oil changes, etc. She looked at me blankly and told me that in all the time she owned the car (5 years?) she had NEVER changed the oil.

Ouch. BTW, not surprisingly, she failed her emissions testing badly.

 

<div class='quotetop'>QUOTE(Eug @ Jan 29 2007, 02:07 PM) [snapback]382373[/snapback]</div>

Makes you want to rush out and buy a used car, doesn't it?

If you took the valve cover off her VW, it would look like a jello mold, just full of sludge. Her rings, valve guides, etc. are all shot.

When you refine crude oil down far enough, you wind up with asphalt cement. Keep your conventional oil in long enough, and you'll wind up with a motor full of something similar to asphalt: not good.

I had an old car that needed a new oil pan. Having run Mobil 1 in that car for years, I took a peek at the old oil pan: squeaky-clean, not a spot of sludge. That agrees very well with Mobil 1's old advertising point, the "oil pan test."

Harry

 

<div class='quotetop'>QUOTE(Earthling @ Jan 29 2007, 02:55 PM) [snapback]382383[/snapback]</div>

That reminds me of something that I saw happen. Several years ago, a friend of mine drove to a New Year's party I had. It happened to be the coldest night ever in several years. He couldn't start his car. Turns out in the six years he owned it, he NEVER changed his oil. Not once.

The oddest part about this whole story: He owned a small bus line with his own buses (I asked, and apparently he did change the oil in them regularly).