I need to buy some ford oil for my mondeo (mk3 1.8 duratec he). Having used shell oil before I know the motor runs smoothly on it, so I looked at the options available:
there is
1. Shell Helix Ultra professional AF 5w-30
2. Shell Helix HX7 professional AF 5w-30
I understand the Lower the MRV value the better the oil is pumped at cold temperatures, and I also know that a higher Viscosity Index is better for protection and often associated with a better oil.
Can anyone hazard a guess at why the (fully synthetic) Helix Ultra AF has a higher MRV (worse) and a Lower Viscosity Index (worse) than the cheaper (semi-synthetic) HX7 AF ??
Has there been a mistake on the TDS PDF data sheets? ... it seems very strange that the cheaper semi-synthetic is outperforming the Helix Ultra synthetic on two key measures :s? Is it a better blend of oil?
Re:
HX7 AF
http://www.epc.shell.com/docs/GPCDOC_Local_TDS_United_Kingdom_Shell_Helix_HX7_Professional_AF_5W-30_(A1_B1_M2C-913A_B)_(en-GB)_TDS.pdf
Ultra AF
http://www.epc.shell.com/docs/GPCDOC_Local_TDS_United_Kingdom_Shell_Helix_Ultra_Professional_AF_5W-30_(A5_B5_M2C-913D)_(en-GB)_TDS.pdf
NB: Also using a viscosity index claculator the HX7 VI value (170) is accurate using the kinematic viscosity @ 40deg and @100deg, whereas the Ultra value (stated as 160) is calculated at 149 using it's kinematic values at 40 and 100!?
VI Tool used: http://www.widman.biz/English/Calculators/VI.html
>> I've checked Liqui Moly, Mobil, and OTHER SHELL oils with this tool and it always delivers the correct VI value based upon the kinematic viscosities at 40 and 100 deg.
Could there be an error in their TDS pdf?
It seems strange that a premium fully synthetyic (albeit probably HC) oil would have a lower VI value and higher MRV value than a semi synthetic for the same application from the same manufacturer!
Advise/Opinions appreciated . . . ?
there is
1. Shell Helix Ultra professional AF 5w-30
2. Shell Helix HX7 professional AF 5w-30
I understand the Lower the MRV value the better the oil is pumped at cold temperatures, and I also know that a higher Viscosity Index is better for protection and often associated with a better oil.
Can anyone hazard a guess at why the (fully synthetic) Helix Ultra AF has a higher MRV (worse) and a Lower Viscosity Index (worse) than the cheaper (semi-synthetic) HX7 AF ??
Has there been a mistake on the TDS PDF data sheets? ... it seems very strange that the cheaper semi-synthetic is outperforming the Helix Ultra synthetic on two key measures :s? Is it a better blend of oil?
Re:
HX7 AF
http://www.epc.shell.com/docs/GPCDOC_Local_TDS_United_Kingdom_Shell_Helix_HX7_Professional_AF_5W-30_(A1_B1_M2C-913A_B)_(en-GB)_TDS.pdf
Ultra AF
http://www.epc.shell.com/docs/GPCDOC_Local_TDS_United_Kingdom_Shell_Helix_Ultra_Professional_AF_5W-30_(A5_B5_M2C-913D)_(en-GB)_TDS.pdf
NB: Also using a viscosity index claculator the HX7 VI value (170) is accurate using the kinematic viscosity @ 40deg and @100deg, whereas the Ultra value (stated as 160) is calculated at 149 using it's kinematic values at 40 and 100!?
VI Tool used: http://www.widman.biz/English/Calculators/VI.html
>> I've checked Liqui Moly, Mobil, and OTHER SHELL oils with this tool and it always delivers the correct VI value based upon the kinematic viscosities at 40 and 100 deg.
Could there be an error in their TDS pdf?
It seems strange that a premium fully synthetyic (albeit probably HC) oil would have a lower VI value and higher MRV value than a semi synthetic for the same application from the same manufacturer!
Advise/Opinions appreciated . . . ?