Synthetic vs Dino revisited

[VeeDubb]

Hi All,

I know this question has been beaten to death, but I am wondering if there is empirically any evidence to show that synthetics are superior to dinos for the common driver. I have noticed that many of the dino oils such as GTX, Chevron Iso-syn, and Motorcraft, and maybe others yield some incredibly good wear rates, and in some cases, better than synthetics. For example, I noticed that not many oils (synthetic or otherwise) yield lower wear rates than an oil like GTX for sub-5000 mile intervals.

I know that *theoretically* synthetics are superior, but it doesn't seem to show on most reports. Now granted, most people probably don't push their cars hard enough to see the benefits of synthetic, which I understand is theoretically better under "extreme conditions." So my question is, for somebody like me who changes their oil every 5-6000 miles and only redline their car maybe once a week and do 50-50 hwy driving, is it really worth it to run synthetic?

[ January 17, 2003, 08:28 AM: Message edited by: VeeDubb ]

 

[Patman]

I think this is a debate that will ring on forever, without any true answer. My theory is this, on paper the synthetics are better, with better low temp performance, better high temp performance, better HTHS numbers, and better long drain capabilities. Nobody will dispute that.

Whether or not this correlates into real world engine longevity is a matter of debate. We've seen many great oil analysis reports on here using conventional oil, showing very low wear numbers. And there are enough true stories of people putting 300k+ on their engines while using just conventional oil. In reality, most people don't keep their cars long enough to even wear out an engine! So it's very hard to say one way or another which is best.

To me, the biggest benefits of synthetic are the fact that in extreme cold you can get better starts, and they have the ability to go for longer intervals, since I hate changing the oil every 3000 miles.

 

[JonS]

I think the only benifit to synthetic is longer drain intervals, and if your outside temps get colded than -40f synthetics would be better. Otherwise, i feel that dino oils have the same wear and almost the same lubricity as synthetic.

 

[westex39]

Everytime I've switched from a dino oil to a synthetic the one thing I noticed most was how much quieter the engine was. This is not just me either, my wife even noticed it without knowing I had made the switch.
the point is, since the engine runs quieter, I would have to assume that it is the reduction of friction that quiets the engine.
Less friction = less wear.

Regards.

 

[Al]

I think Patman covered it. I would only add that there is extra security in case your engine overheats. It could make the difference whether you wind up sitting along the road or drive a few extra miles to get help. Also its probably likely that engine damage may not occur during a high tmperature episode.

 

[Patman]

Al, I think some of that high temperature protection will exist with some of the new SL dinos though. Looking at some of the flash points on some of these oils, they are not that far off the synthetics. I've noticed a trend where the synthetics flash points are coming down, while the dinos are going up. So the gap has narrowed. I remember when I first got interested in oil and synthetics, the big name synthetics had flash points of 500F, or close to it, but now they are closer to 450F. A few dino oils out there are right at this mark too.

 

[jason07-1zzfe]

Yeah and M1 now says it protects to 400F. It used to say 475F. Someone actually asked about that on the "Ask Mobil1" section of their website, but they avoided that part of the question.

 

[darrenc]

Don't forget about deposit control advantages with PAO/Ester based syns. This is an advantage that many overlook. Some engines sludge up pretty heavily even when the oil is changed at a high frequency.

[ January 17, 2003, 10:44 AM: Message edited by: darrenc ]

 

[TooSlick]

VeeDub,

The PAO/Ester synlubes thermally decompose much cleaner than do petroleum oils. This is not something that you can see at all through oil analysis however. As a result of this, you will see a significant reduction in turbocharger, piston/ ring and exhaust valve deposits on engines that run PAO/Ester synthetic oils. Petroleum lubes will coke and form these types of deposits even if they are changed frequently ....

High temp deposit formation is of the main reasons why VW recommends only synthetic lubes for the TDI diesel engines ....

 

[HOndaGuy]

i think with synthetics, your engine will be much much cleaner and more operative than a regular dino car driven the same 150,000 miles thats sludged up. Basically, with synthetics, you don't have to worry about 3000 changes, better cold starts, better high temp protection, and engine cleanliness. If you think about it, synthetic oil and filter cost about(im talking mostly mobil 1) around 30 bucks with a decent filter like the bosch premium. Youd be paying maybe 2 bucks less at jiffy lube for a crappy oil change with dino oil and most of the time they don't even change the filter(fram go figure).

 

[TooSlick]

VeeDub,

To more directly answer your question, I think you can get good long term results with the newer Group II petroleum oils with 5000 mile change intervals, provided the driving conditions aren't very severe - In that case I think that 3000 mile changes are still a good idea. Of course I also think you can run Mobil 1 for 6000-7500 miles even under severe operating conditions, so that would be my choice.

Petroleum oils are better than they were five years ago, but synthetics have gotten better as well. Until recently most of the improvements in petroleum lubes came from better chemical additives and these same additives also work with synthetic basestocks. The synthetic basestocks have inherently better physical/chemical properties and respond very well to properly formulated additives. So the idea that petroleum oils will ever "catch up" with the best synthetic oils is wishful thinking.

TooSlick

 

[edwardh1]

help
where are the Groups (I II III ) explained for a new person and what oil is in what group

 

[Ray H]

quote:

---

Originally posted by edwardh1:
help
where are the Groups (I II III ) explained for a new person and what oil is in what group

---

Quick (sort of...) and dirty (definitely!):

Group I: I believe is a solvent refined oil that's undegone moderate "hydroprocessing" - exposed to hydrogen gas in the presence of heat, pressure and a catalyst. The chemical reactions form a recoverable sludge of waxes, undesirable cyclic aromatics (great solvents, terrible lubricants and they oxidize readily), and sulfurics (that in the presence of moisture form acidic corrosives - not a good thing in your engine) that can be processed for commercial use. Less nasty stuff than straight solvent refined base stocks, but with only a mildly higher viscosity index.

Group II: More of the same with less recoverable sludge because some of it is converted (isomerized) into desirable parrafin oil. Higher viscosity index. A somewhat higher degree of hydro-processing/finishing results in a subcategory, Group II+ - close to Group III but not quite a high enough viscosity index to be considered a Group III.

Group III: More of the same, higher pressure, higher heat. Little recoverable sludge for the same reason above. Even higher viscosity index (not too awfully far from PAOs). This is the great controversy - is a Group III a synthetic or not? It's not a PAO, but it IS a -very- low wax, low sulfer, and low aromatic parrafin oil with many of the desirable properties of PAOs. Most over-the-counter synthetic oils (including Castrol Syntec and Pennzoil Full Synthetic) are actually Group III base stocks blended with an additive package now. Mobil 1 is about the only OTC PAO based synthetic these days - and, it, too, has its own additive package, as well as Group V base stocks. Exxon-Mobil, ironically, is one of the largest American producers of Group III base stocks. Chevron-Texaco is too. Castrol took some heat when it reformulated Syntec with Group III base stocks. Exxon-Mobil cried foul (Exxon-Mobil does, after all, have a lot invested in the infrastructure to produce commercial quantities of PAOs.). The National Advertising Division of the Better Business Bureau heard the case and determined that isomerization (Group III) was just as valid a process on the road to the definition of "synthetic" as polymerization (Group IV (PAOs) and Group V - everything else not covered by Groups I - IV). Both parties conditionally agreed that the NAD's finding would be accepted in liue of a court trial. Alleged performance issues aside, much of the controversy also involves the fact that Group III base stocks cost the refiners about half as much to produce as PAOs, but the "full synthetics" using Group IIIs as their base stocks cost consumers nearly as much to buy as Mobil I. Group III base stocks do not have as high a viscosity index as Group IV and V base stocks, but generally the difference can be made up in the additive package.

If you understood ANY of this, you're now a certified lubrication engineer...

[ January 20, 2003, 01:24 AM: Message edited by: Ray H ]

 

[Flimflam]

Patman, you are super, brilliant. You are a genius. It's true, what you say. The better SL classification mineral oils are not that far off from synthetic oils in some important performance parameters.

You are right when you say both minerals and syn's have flash point of 450 deg F these days.

The slick ads have actors saying, "oh, thank goodness we have El Snake-O synthetic in our car here in the Gobi desert." But what they don't say is, many minerals can give the same extreme temperature protection.

My friends tell me to use synthetic in the hot summer months. They tell me I won't lose oil due to volatilzation. Well, I use monograde mineral oil with flash point of 445-450 deg F, and it is so resistant to volatility boil-off even in downtown Houston traffic jams in July & August, I've given up looking at my dipstick. I just know my 5.5 quarts is all there.