Originally Posted by Crimson600+HP (Post 69926)

I didn't know that the Boss and track pack cars ran 5w-50 for protection reasons. Given the nature of how I treat my car, I think this is probably the right move to do.

Originally Posted by re-rx7 (Post 69912)

You guys are all very off on your understanding of motor oils.

Originally Posted by re-rx7 (Post 70132)

Study hard.

http://www.bobistheoilguy.com/motor-oil-101/

Originally Posted by Disturbed (Post 69895)

However, UOA's have already shown that 10w30 Amsoil, and even Royal Purple are superior, at least on the analysis sheet. Ford's engineers are not stupid, but what their not telling you, is about the quality of their oil. Under street racing conditions or light tracking, the 5w50 Motorcraft is shearing to a light 5w40 at running tempurature. Under extreme conditions, its even shearing down to a heavy 5w30.

By this, I would rather run a quality oil thats ALWAYS a 30w oil with minimal shearing. Amsoil 10w30 is my choice. And the 10w is soley because we live in Texas.

With a quality 30w, your going to have the same if not better protection, and slightly improved fuel mileage. If your worried about warranty, you can use the cheaper Motorcraft. The same engine runs 5w20 in non track pack AND non boss cars. They assume its your daily driver (the base model), not a race car.

Pick the oil for your intended use, and pick a quality one.

Originally Posted by re-rx7 (Post 70146)

Let me ask you this. WHat kinf od wear does that 50 put on an engine at startup?

Originally Posted by BV600 (Post 70176)

Great thread I read awhile back on SVTP suggest you 5w-50 users/believers to read.
http://www.svtperformance.com/forums...ight=viscosity

Originally Posted by Disturbed (Post 70172)

At startup? The 50 isnt as relevant for startup protection as the the first Winter grade number is, and what your particular climate is. Startup engine protection relies heavily on the cold viscosity of your winter grade. Not sure if your attempting to troll or what, because you have yet to actually tell me where the flaw is in said knowledge. If the next response is anything but, I will probably move on to other, more important threads.

Not trying to be offensive at all. But when someone shares knowledge of something they have looked deeply into to help those with questions, theres usually better and / or more detailed responses then "You guys are all very off on your understanding of motor oils." How about you share your knowledge, instead of making a generalized browbeat of others, and leave some details as to how you came to that conclusion.

Originally Posted by re-rx7 (Post 70181)

My point is simple. YOu dont always have to have a thicker oil if your going to be racing. Conditions are the biggest consideration and a thicker oil can do more harm then good in some situations. In my mind there is no need for a 50 in the stang. Wouldnt you agree?

I use a Penn ultra and it is better then entry level AMsoil in alot of test at a far cheaper price.

Originally Posted by Disturbed (Post 70183)

Yes I understand your point. This is exactly why I chose a non-shearing 30w for my own car. What you dont realize is why ford suggests the 50 weight. Its because that garbage shears down to a 30 if your actually going hard on the track in the summer time.

They dont expect it to be a 50 at running temp at the track. 50 would be overkill IF it stayed at 50. But it doesnt.

And, thicker oil like 50w doesnt mean shit for startup. 0w50 in harsh winter cold start = fine.
If you run 15w20 in the winter, its just as bad as 15w50. First number is the key for startup. Again, its the winter grade number that determines its cold start viscosity. If Ford's oil didnt shear 1/3 of its viscosity under tracking then they would be suggesting lighter oil. Period.

Originally Posted by re-rx7 (Post 70189)

Obviously. I do believe amsoil to be overpriced.