15W-50 in all his exotics in Utah year round. I'm going in for my 5K soon and am going to put some degree of Mobil 1 Tri-Syn. What should I do? ahhhhhhhhhhhhhhhhhh.

Oh, btw, have we ever worked out details on the convoy to H20?

 

Jim. You don't list Castrol Syntech. Dealer uses this. Should I start bringing my own Mobil0W-30?

 

..and I bet that is what Jason is using. My answer is 5w-30, for the reasons stated in the above post. Did you know that F1 teams are now using a straight zero weight Mobil 1oil for qualifying, Nascar as well? What you want is a viscosity the will provide adequate shear protection at the lightest weight possible. Just like Jason and Me, you need to decide what is best based on what you know. There a lot of people who know a lot about engines that don't agree on many engine building or set up methods. JIM

 

Great info, thanks Jim!

 

.... using a hydroisomerized process to chemically change wax-creating molecules. This is great except for the fact that they call the resulting oil product 'synthetic' when if fact it is not! At least it's not in the sense of the word we all understand. This perhaps explains why Castrol Syntec shows no increase in horsepower over mineral-based oil. There is a very good write up on this subject in Patrick Bedard's column in the November issue of 'Car and Driver'. It's a RIP OFF, take Mobil 1 with you.

 

putting Castrol in MY car.

 

Lighter oils maintain a lower oil pressure and are easier to pump but they also deliver a greater volume of oil throughout the engine. Higher weight oils are exactly the opposite. So you get the following benefits from lighter weight oil: more power, better cooling, better gas mileage and better lubrication. The numbers 10, 20, 30 etc. relate to viscosity and are a measure of shear strength and resistance to flow, not adhesion. It is NOT the pressure from the oil pump that keeps the crank separated from the crank bearing. Rather it is the hydro dynamic bearing action of the oil FILM that resists the high pressures exerted on these moving parts. If the oil is too thick this film may not form or the oil may not even get into the bearing space. Too thin of an oil will not have the shear strength to prevent contact under high pressure. Trust me when I say Mobil 1 is not selling oils that have these issues to any great extent. So consider 0W 30 for example, the W means winter, not weight and it is an indication of the oils suitability for winter use and in this case it doesn't get any better than 0. The 30 number means this oil will not thin any more than straight 30-weight oil at 100 degrees centigrade. But there is far more to rating oil than these is simple numbers. I guarantee that to different brands of 5W-30 will have different viscosity when tested in a lab. Mobil 1 0W-30 has a flash point of 460 degrees F and you will never get close to that oil sump temp even if you pull a trailer through the Mojave desert. Mobil 1 15W 50 as a comparison has a flash point of 475 degrees F. Interestingly Mobil 1 0w-30 has a higher viscosity index than Mobil 1 15W-50 however this make sense because 15W 50 has a higher viscosity range of 35 (this does not mean 0W-30 is thicker than Mobil 1 15W-50). The implication that an '0W- whatever' oil is not good for summer driving is not correct. The problem with cold start up is getting oil to the bearing and here lighter weight oil will flow there faster. Oil does drain away from engine parts when a motor is at rest but this applies to ALL oils, 50 weight will drain away more slowly but it still drains away and adhesion properties of oils very independently of weights between manufacturers. As to John S's post about Mobil 1 OW-40 it looks great however we can't buy it in the US. Oil is very complicated and it can't be covered in anything short of a book. All we need to do is follow Audi's oil recommendations and USE SYNTHETIC oil. If you want to use 10w 40 go ahead, I personally would not for many reasons but do think it is more important to stick with good synthetics which include Mobil 1, Torco, Redline, Amsoil and Royal Purple than it is to pick the perfect multi grade rating.. Unfortunately many oils marketed as synthetics are NOT so they should be avoided. JIM

 

Thanks, Jim. I'm sticking with my current Mobil1 5W 30 for now.

 

Local Audi/Porsche dealer swears by it, and so do I now!!

 

Mobil 1 only became a 100% synthetic with this newest formula, the Tri-Synth. People just don't read labels very well. Castrol Syntec is about 5% synthetic as Mobil 1 used to be.