By oil change, i mean the 5.1 quarts of oil only.

 

Yea about $50 after buying all the oil, filter, and paying the Auto-hobby shop on base for Lift time.

 

There are other bene's as far as using Amsoil w/extended drain intervals.
1. The oil has a low pour point of ≤ -45 F, normal petro is likely -20 F (or so), much better lube when cold(like now! - easier on battery and electricals when starting etc.)
2. Higher flash point than petro.(less evaporation when hot).
3. Less metal wear on almost all industry tests (4-ball etc) than even all synthetics.
4. Very high detergency (cleans engine and deposits it in filter better).
5. A few other features (higher acid neutralization, etc)

On the $ side: Do the math -Amsoil about 15K per year at $50 vs dyno at 5 changes (
@3k) per year. This does not take into account your time spent to do these.

Amsoil is almost a no brainer if you compare. Look at some to the oil comparisons on the web site (not sure where to find them) but it is educational.

One thing is the oil has to be used in already sound engines. It doesn't fix things.

However it is true that change at manuf's intervals would do almost the same for engine wear so it is really the users preference about which way to go. And when racing the machine most bets are off because a different oil is needed.

 

While your motor oil may still be retaining plenty of lubricating properties at 35,000 miles there is still the issue of contaminants, you still have to replace the oil filter every 5,000 - 7,500 miles and oil filters don't get rid of the acids that will be building up in your very old oil.


A good filter and a decent base III synthetic (mobil one, castrol syntec) changed every 4 - 5K miles will protect your engine better long term than going that long on a true synthetic oil.

 

The filter I use is the Amsoil EaO labeled filter. Amsoil indicates for normal use in cars the EaO should be good for 1year and 30K miles. A little hard to believe, especially with the absurdly small oil filters that manuf's now put in engines.

However most of Amsoil's claims seem to be very well documented and historically seem to hold up. I am making the assumption that they did their usually excellent homework on the EaO filters as well.

So far I have never had a reason to doubt them. And they do publish lists of cars that the extended intervals are not recommended for so they are looking at that issue as well.

Amsoil has aalso gotten users feedback of over-the-road truckers with 300+K on their oil without changing (the filters did get changed).

FYI: I owned an 83? diesel Rabbit which I did the Amsoil extended drain intervals on for 3 years and 60k, then sold it to a gent who, at last contact, had 275K on the clock and still purring. My history of this oil has been excellent.

As I say if you are uncomfortable with this whole idea then its best not to do it.

 

[QUOTE=JLUDE,Feb 11 2011, 08:43 AM]

 

I'm very curious about this. This is the first time I've heard about any real engine performance differences associated with running a synthetic oil.

Can anyone else chime in on these claims? Is there something to this?

 

That is quite an impressive analysis, good batch of tests.

I did mine with Analysts in Chicago and they do a reasonable job as well. It would have been extra nice to see a column of desirable maximum/minimum levels of additives, wear metals and properties in that table though. I always like to make those comparisions for my own warm fuzzy feeling.

For Deepblue, I have seen thermal readings in Amsoil literature concerning Engine, Transmission and differential temperatures that have been lowered when using Amsoil but not sure its findable. The lube flows better and does transfer temperature better I suspect.
Mileage will increase due to cold starting since Amsoil flows easier when cold, and perhaps some a more slippery oil film. The long term trucker results always showed improved mileage by several tenths of a mpg. Say at 3 mpg and lots of fuel it saved them quite a bit of money.
I am not sure I have ever seen dyno-tests with and without Amsoil but those would have been interesting. An HP boost would certainly get some folks interested.

 

Interesting. I have mostly ignored synthetic oils in the past, since I don't turbocharge or track my cars, but if those claims are true I might have to give it a hard look.

 

I get he Amsoil with the 17k-25k life and the filter the reccomend to go with it for the same interval. I change at the 17k interval (servere use) because I do a lot of autox which is probably being more cautious than I need, of course the years that the 1 year mark hits before this mileage I change it at the 1 year mark. (just more detail on my data point and yea my autox s2k is my DD and i used to have to drive a lot more than I do now lol)

as fo changing every 4-5k, that is entirely unnecissary with any full synthetic, that is more what you should do with modern dino oils. the old mechanic rule of 3k for reg and 5k for syn is outdated in modern engines wiht modern oil. There is a big reason the honda interval is longer. Most modern Dino oild are good for 5k or so and most modern synthetics (i.e mobil 1) are good for like 7.5k