Comparing syn. and conv. viscosities

[afoulk]

Please bear with me guys, as I'm still pretty new to this "oil" thing. I was looking at the datasheets of the 2 different oils I was previously considering for my jeep. First one was QS Horsepower (synthetic) and second was Pennzoil conventional (conventional). When looking at the viscosities for the YB, its 63.9 @ 40*C and 10.5 @ 100*C for the 5w30. The QS is ofcourse slightly lower, especially at 40*C. My question is, the QS in a 10w30 is 63.9 and 10.8. Does this mean its basically the same viscosity as a conventional 5w30? Would this offer anymore protection? and I know this probably seems simple, but would it still flow any better than the conv. 5w30 or would it be about the same?

 

[scoobie]

the Quaker State Synthetic 5w30 offers more protection that the synthetic 10w30.
you need to look at the viscosity at -30 or -35. a conventional oil at that temperature is kind of like honey. Dr. Haas explains it really well in the "Interesting Articles" forum.
you can also read the thread i started about 5w25 good or bad?
http://www.bobistheoilguy.com/forums/ubb...933#Post1261933
currently i run synthetic mix of 5w30 and 5w20 in my Subaru, and in my Mitsubishi colt.

 

[FrankN4]

Kinda, sorta, little bit confusing.

The number before the W such as 5W or 10W refers to the pumping and cranking viscosity measured in cp and measured at a given temperature. If both a synthetic and a conventional oil are labeled 5W or 10W, they must both meet the same pumping and cranking requirements.

The 40c and 100C measurements are the viscosity in cSt of the oil at 104F and 212F. The spread between the two determines the viscosity index. The higher the viscosity index, the better, BUT, you have to compare the viscosity index within grades. You cannot compare the viscosity index(VI) of a 5w30 and a 10w30.

A 30 grade oil will have a 100C cSt of 9.3 to 12.49. The 100C number tells you the grade of the oil. Mobil 1 has a 5w30 with a 40C of 64.8 and a 100C of 11.3. Their 10w30 has a 40C of 62 and a 100C of 10. In this example, the 5w30 is more viscous/thicker, than the 10w30, BUT, they are both 30 grade oils with different cold cranking/pumping specifications. The 5W will likely require more viscosity index improvers.

In the real world, the 10w30 synthetic is going to pump/crank as well as or even better than the 5w30 conventional.(look at some product data sheets) It is going to require less viscosity index improvers thus change viscosity less with temperature changes.

I know you are not looking for advise, but I can't help myself. If your Jeep is under warranty, use a full synthetic version of what they spec, and since you are looking within SOPUS products, and since you are inquiring about 30 grade oils, Pennzoil Platinum or Quaker State 5w30 or 10w30 would be good.

 

[kaboom10]

Thanx?????

 

[BuickGN]

Originally Posted By: scoobie
the Quaker State Synthetic 5w30 offers more protection that the synthetic 10w30.
you need to look at the viscosity at -30 or -35. a conventional oil at that temperature is kind of like honey. Dr. Haas explains it really well in the "Interesting Articles" forum.
you can also read the thread i started about 5w25 good or bad?
http://www.bobistheoilguy.com/forums/ubb...933#Post1261933
currently i run synthetic mix of 5w30 and 5w20 in my Subaru, and in my Mitsubishi colt.


Another blanket statement.

The synthetic 5w30 may offer more protection than a 10w30 synthetic if you're starting your car in extremely cold temps and that's it. Otherwise the 10w30 is going to be more shear stable and have a higher HTHS and all around better during normal use.

How often is the car started in -30 or -35 temps?

 

[afoulk]

well, my thinking was run the torque power in a 5w30 in the winter because, again, I see the 40*C viscosity is lower than even the 5w30 conventional, but then in the warmer months, run the 10w30 since it would be very close in viscosity to a the conv. 5w30 when colder, but hopefully offer more protection once the engine is hot. I just wasn't sure if I was reading into the specs right.

But, this was something I was playing around with in my head a little while ago. I'm currently thinking about running YB or Chevron 5w30 to cut back on costs. Still not sure what I wanna do.

 

[chevrofreak]

Originally Posted By: BuickGN
Another blanket statement.


He likes to make those.