A good point you make, I shoulda stated I look for the 2-4 percent power increase in syn's. Not their overall anti wear properties only.

I got on the synthetic band wagon when I built my current engine for my truck. I fugured every little bit helps, within reason. I"m running Amsoil 10-30 and have passed 10,300 on it.
I'll be sending in a sample soon for testing. Hopefully I'll run it for a full year, 15,000 to 20,000 miles. I also run a Frantz sub-micronic bypass filter along with my Delco spin on. I've changed the spin-on filter 2 times and the TP in my Frantz 3 times. Each time, I cut the spin-on open and it was clean! Nothing inside but oil. When my Amsoil is gone, i'm going back to petro oil but keeping the same schedule. With proper filtration, I can get the same milage out of petro oil as with any synthetic, but at a much lower cost. Yesterday I picked up a case of Chevron for 49 cents a quart and Checker.
I have the Frantz on all 3 vehicles so that I can extend my oil changes because I"m tired of all the 5 gallon cans of used oil that stack up in my garage.

In a perfect world, most oils will last tens of thousands of miles without needing changing. The days of 3000 mile oil changes are fading fast. When asking people why they change it so often, most say, "cause my daddy did it that way and his daddy too!". Well, 50 years ago, you needed to change it that often. Engines ran dirty, air filters were crappy and gas sucked and most people drove on dirt roads. All that has changed with fuel injection and engines that run very clean.

Europe has had 7500 and 10,000 mile oil change intervals on their new cars for a few years now. Oil companies are seeing the shift in thinking and slowly making the advertising changes to reflect the reality of todays superior oils and effecient engines.

The whole thing boils down to personal preferance on vehicle maintance. If you want to do some really good reading on all kinds of oils and all brands of filters, Here is a good place.

I had no idea that they are using that oil but I will tell you from experience that I already knew that as i've blown a few engines up from oil related issues. This is my other id> http://www.hotrodders.com/showpost....844&postcount=5
I know in my heart Amsoil is the best but not cost effective.

I run a 20+k engine for drag racing
then change my oil almost montly when racing (when my car run ie summer time)

Using Valvoline 20-50, today i have pick up MoBil1 15-50,
over twice the price of standard oil btw..

But i guess i will stick on mobil1, now the breakin is well done
i will try to run only syn. on this engine.. But i'm a serious oil changer,
dont know how long i will keep it on the engine
May be when i will flush it i will keep it for my daily car i think

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You may not need to change the oil as often.
What you should do is on your next change have an oil analyst done for the $15 it will cost you it would be worth it for a couple of reasons.

Too see if your oil is still good (that will depend on clearances in engine such as bypass etc.)

Most important to see if your running the proper grade (also depends on how engine was built)

You may find your getting oil shearing with 15w50. (slight chance)
You made a good move on the change of brands and the biggest benefit will be the synthetic creates a positive charge and will stick and keep the parts protected for the once a week start up.
People get scared with oil weight and think thick but there were three cars that i know of last week at Pocono that ran the race with 5W30 Mobil 1.

i know the oil was probably still very good when i change it, but i'm still think when you hit hard on an engine the oil may loose lot of its original quality pretty quick, so my engine are too costly to take any chance whit that, i like fresh oil

btw since i run on the road then goes to the track (2hours road, & it still a street car), the 15-50 or 20-50 are heated when i race, and they are became thin when heated & my car are stored the winter, the 5-30 is like water even at cold temp, i dont like this very mutch even if i have 70psi oil press. i have never used thin oil in my life until now, i'm refraint a bit.. Unless someone can have serious valid reason to do so, i can't find reason to use light oil, more is the viscosity better is oil in my opignion.

I understand what your saying and that is why you should spend the money for an oil analysts so you know for sure.
Example:
The class action suit against Mercedes for not posting clear enough the oil had to be 0W30 or 0W40 Mobil-1 and these folks were putting in Castol 20-50 and engines were going south at 50,000 miles.
look at the Viper requirements, 4.6 fords and the Vettes were in the 5w-20 to 30 range.
The F250 diesel is sheering all 15w40 and even Mobil-1 15w50, this is being kept hush/hush but there are a lot of people working on the problem as this is a serious wear issue for the engine. Of all oils tested the Mobil-1 is holding up the best but after 2,000 miles the 15w50 is sheering to a 15w30 bad news. (this is only in the new f250 engine diesels)
IT ALL DEPENDS ON HOW ENGINE IS BUILT!

You have a lot of money in your engine so you should make sure you have the right grade. By the way 0W20 and 15W50 both have a Viscosity Index of about 8.

I really should not have posted this as don't want to piss anyone off, now the person that printed the previous letter (Amway or Amosoil) should be pissed on and I did, so I'm leaving this thing alone. good luck.

Doesn't it depend on driving conditions above all else?
Who do you work for?

Yes, BUT of most importance how the engine was built!
This was unimportant 15 years ago, today its of 1st importance
2nd is driving habits and temperature.

I no longer work for an oil company, formulated and worked in testing for around three years. Hated the geeks I worked with and had to go!