its pretty close to the same base just with a bigger additive package in it. they did it imo to keep up with amsoil, royal purple and redline. because they were cutting into thier oil profits with extended drain.

 

I don't believe that castrol syntech is 100% synthetic.

 

I never knew that.

 

They have both a partial and full synthetic. You have to be careful which you buy.

 

no syntec is not fully synthetic it contains some group 3 base stock (organic oil) it was given the right to call itself syn. when synthetics were getting started.

 

I pesonally use synthetic in all my cars. I dont really know how much of a difference it makes but i just try to do what ever i can to keep them running as good as possible for as long as possible. I personally use mobile 1, i would have to say that it is the best.

 

What would be the difference?

 

what about royal purple?

 

I have herad good things about Royal Purple.

 

Does anyone else see something wrong with someone that has used just one of anything saying they think it is the best with no comparisons involved? The above comments are generally informative and appreciated but what good is it to say I use Mobil 1 and think it is the best w/o something to base that on other than no obvious problems from the Mobil 1? I have no reason to think Mobil 1 is or is not the best. The Amsoil link was interesting until I saw the Jesus portion. If they are relying on devine intervention to prevent wear, I am in trouble.