Got this off of fordf150.net site, interesting explaination.
For 1997 engines and newer: In all ambient temperatures, the goal should be the utilization a motor oil of the thinnest SAE grade viscosity rating which provides undegradable film strength at pressures down to 10 psig. The goal being the "thickest" viscosity @ normal operating temp, plus a 10% overshoot. The achieve this, the optimum centistoke viscosity @ 212 F, must be between 8.2, and 11.3 (the closer to 11.3, the better). Using an oil exhibiting cSt above 12, actually begins to generate some friction within itself. You won't lose film strength, but will begin losing efficiency (horsepower). In our lab, we measure this as volumetric and mechanical efficiency.
It is important to note, that our testing is only quanitfying the lubricative and efficency characteristics of these oils, and not the "total package" which includes contaminate retension, resistence to sludge, cold weather performance, etc.
We have only researched a few oil brands, but this is what our testing indicate to date relative to cSt @ 212 F:
Synthetics / semi synthetics:
Mobil 1 SuperSyn 5w30 - 9.7
10W-30 - 9.8
Mobil Dr Cl Blnd 5w30 - 10.5
10W-30 - 10.5
Pennzoil Syn Blnd 5w30 - 10.5
10W-30 - 10.5
Quaker State Synthetic Blend
5W-20 - 8.1
5w30 - 11.0
10W-30 -10.5
Motorcraft Syn Blnd 5W-20 - 9.0
Solvent refined base (conventional):
Mobil 5w30 - 10.5
10W-30 - 10.5
Quaker State 5W-20 - 8.1
5w30 - 10.7
10W-30 - 10.5
Hydrocracked refined base:
Conoco 5w30 - 11.0
10W-30 - 10.7
Motorcraft 5w30 - 11.2
10W-30 - 11.0
In summary, it may seem we are "splitting hairs" here, but it all comes down to the application, as the data would indicate all the above oils (except both Quaker State 5W-20s) accomodate the
aforementioned criteria.
In our applications we only recommend synthetics where high performance equipment experiences consistent operating temperatures above 264 F. This is usually an application where the manufacturer has deemed it cost prohibive to install an oil cooler. Today, many truck V-8s come equiped from the factory with oil coolers. I know for a fact most Ford 4.6 & 5.4Ls do.
It is our opinion, the oils constructed of hydrocracked bases represent the best combination of performance and cost.
For 1997 engines and newer: In all ambient temperatures, the goal should be the utilization a motor oil of the thinnest SAE grade viscosity rating which provides undegradable film strength at pressures down to 10 psig. The goal being the "thickest" viscosity @ normal operating temp, plus a 10% overshoot. The achieve this, the optimum centistoke viscosity @ 212 F, must be between 8.2, and 11.3 (the closer to 11.3, the better). Using an oil exhibiting cSt above 12, actually begins to generate some friction within itself. You won't lose film strength, but will begin losing efficiency (horsepower). In our lab, we measure this as volumetric and mechanical efficiency.
It is important to note, that our testing is only quanitfying the lubricative and efficency characteristics of these oils, and not the "total package" which includes contaminate retension, resistence to sludge, cold weather performance, etc.
We have only researched a few oil brands, but this is what our testing indicate to date relative to cSt @ 212 F:
Synthetics / semi synthetics:
Mobil 1 SuperSyn 5w30 - 9.7
10W-30 - 9.8
Mobil Dr Cl Blnd 5w30 - 10.5
10W-30 - 10.5
Pennzoil Syn Blnd 5w30 - 10.5
10W-30 - 10.5
Quaker State Synthetic Blend
5W-20 - 8.1
5w30 - 11.0
10W-30 -10.5
Motorcraft Syn Blnd 5W-20 - 9.0
Solvent refined base (conventional):
Mobil 5w30 - 10.5
10W-30 - 10.5
Quaker State 5W-20 - 8.1
5w30 - 10.7
10W-30 - 10.5
Hydrocracked refined base:
Conoco 5w30 - 11.0
10W-30 - 10.7
Motorcraft 5w30 - 11.2
10W-30 - 11.0
In summary, it may seem we are "splitting hairs" here, but it all comes down to the application, as the data would indicate all the above oils (except both Quaker State 5W-20s) accomodate the
aforementioned criteria.
In our applications we only recommend synthetics where high performance equipment experiences consistent operating temperatures above 264 F. This is usually an application where the manufacturer has deemed it cost prohibive to install an oil cooler. Today, many truck V-8s come equiped from the factory with oil coolers. I know for a fact most Ford 4.6 & 5.4Ls do.
It is our opinion, the oils constructed of hydrocracked bases represent the best combination of performance and cost.
