Its all definetly dinosaur juice, synthetic only implies it's synthesis beyond natural purity levels

 

Thanks a lot guys. I will have to go with the Synthetic oil.

 

Will Synthetic oil make piston slap louder?

 

I use mobil1 also, 5w-30 in the winter and 10w-30 in the summer. I put just regular oil in her one time just to see if it really made a difference and I ended up changing my oil back to mobil1 in less than 1500 miles. Just use the good stuff and she be good to you.

 

I used mobil 1 but in my new engine I'm not using the synthetic. Not worth it. Regular oil protects just about the same from what I can tell.

 

Some more info on synthetic oil and why it is better than "dino oil."
http://www.hatcocorporation.com/page...t_syn_lub.html

 

my dad manages a oil changed and said that in all the oil mags he gets the the W stands for winter not weight. 0w-30 is actually a thicker oil and not good for the winter.

 

You're right and wrong there. If I'm not mistaken, the "W" refers to its winter weight (so you're right there) but the lower the number, the lighter the weight, hence, a 0W-30 IS a good winter oil. Something like a 20W-50 is NOT a good winter oil. The number beside the W is its cold temperature viscosity rating ... the 0W, 5W, 10W, etc. The second number is its hot viscosity rating (basically the rating of the oil at normal engine operating temperature). The higher the number, the higher the viscosity, and the thicker the oil. For winter time, you want a lower number, less viscous oil. That's why a lot of guys will run 5W-30 in the winter, and 10W-30 in the summer.

 

I have used synthetic oil in my '96 LT1 since it drove off the dealer lot.

Synthetic oil allows for new viscosity oils that aren't possible with conventional petroleum based oil. Mobil 1 had a 0W-50 oil that I used to run in a 235hp 2.8L V6 (yes, GM). The lighter the oil, the less resistance = better gas mileage and more power. That's pretty cool! All I know is, that engine never launched, so the oil has to work.

 

Copied from Popular Mechanics.com

Viscosity
Viscosity (a fluid's resistance to flow) is rated at 0° F (represented by the number preceding the "W" [for Winter]) and at 212° F (represented by the second number in the viscosity designation). So 10W-30 oil has less viscosity when cold and hot than does 20W-50. Motor oil thins as it heats and thickens as it cools. So, with the right additives to help it resist thinning too much, an oil can be rated for one viscosity when cold, another when hot. The more resistant it is to thinning, the higher the second number (10W-40 versus 10W-30, for example) and that's good. Within reason, thicker oil generally seals better and maintains a better film of lubrication between moving parts.

At the low-temperature end, oil has to be resistant to thickening so that it flows more easily to all the moving parts in your engine. Also, if the oil is too thick the engine requires more energy to turn the crankshaft, which is partly submerged in a bath of oil. Excessive thickness can make it harder to start the engine, which reduces fuel economy. A 5W oil is typically what's recommended for winter use. However, synthetic oils can be formulated to flow even more easily when cold, so they are able to pass tests that meet the 0W rating.

Once the engine is running, the oil heats up. The second number in the viscosity rating--the "40" in 10W-40, for example--tells you that the oil will stay thicker at high temperatures than one with a lower second number--the "30" in 10W-30, for example. What's really important is that you use the oil viscosity your car's owner's manual recommends.