Gary, if it never gets below 50 degrees, why not run SAE 30 all year?
is there anyone out there using single weight oil?
- Thread starter BarkerMan
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Us old timers agree with you. If you are up to changing the viscosity with the weather I think that single weight oil does a good job.
Originally Posted By: bruce381
Originally Posted By: G-MAN
If VI improvers are designed to approximate the HTHS of a Newtonian oil under the conditions of the HTHS test, I am of the opinion that if you push a VI laden oil more severely than what the HTHS test simulates, it will have a lower HTHS than an oil with no VI improvers.
No not any lower than the base oil vis that you start with unless the base stock is sheared, all you can lose is the VII vis kick and normally you may lose about 50-70% of that.
That's my point. Say you test a 5w30 and a straight 30, both having a HTHS of 2.9. But you push both oils way beyond the shearing they experience in the HTHS test. Under those conditions the SAE 30 will have a higher HTHS because at some point the VI improvers in the 5w30 will crash leaving nothing but the 5 cSt base oil. With the SAE 30, you've always got a 10 cSt (approx) base oil to "fall back on."
Originally Posted By: G-MAN
If VI improvers are designed to approximate the HTHS of a Newtonian oil under the conditions of the HTHS test, I am of the opinion that if you push a VI laden oil more severely than what the HTHS test simulates, it will have a lower HTHS than an oil with no VI improvers.
No not any lower than the base oil vis that you start with unless the base stock is sheared, all you can lose is the VII vis kick and normally you may lose about 50-70% of that.
That's my point. Say you test a 5w30 and a straight 30, both having a HTHS of 2.9. But you push both oils way beyond the shearing they experience in the HTHS test. Under those conditions the SAE 30 will have a higher HTHS because at some point the VI improvers in the 5w30 will crash leaving nothing but the 5 cSt base oil. With the SAE 30, you've always got a 10 cSt (approx) base oil to "fall back on."
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