AlfaRonny Posted August 13, 2009 Share Posted August 13, 2009 Om man jämför en 5W-50 (Helsyntet) med en 20W-50 (mineral) så skall dom väl vara lika tjocka vid full arbets temp? //R Quote Link to comment Share on other sites More sharing options...
kimmen Posted August 13, 2009 Share Posted August 13, 2009 (edited) Om man jämför en 5W-50 (Helsyntet) med en 20W-50 (mineral) så skall dom väl vara lika tjocka vid full arbets temp? //R Ja, vid 100 grader. Edited August 13, 2009 by kimmen Quote Link to comment Share on other sites More sharing options...
kimmen Posted August 13, 2009 Share Posted August 13, 2009 Lite att tänka på... At which temperature does an oil flow better? There is no temperature where oil suddenly starts to flow better. A 10W/40 for example will flow between -25C and 100C or more, but there is some difference in the rate of flow! (True viscosity at -25C is about 7000 Centistoke(cSt) units, dropping to 14 at 100C. "Viscosity" is really just another name for "rate of flow".) The correct question is at what (sump) temperature is an oil at a viscosity that suits a modern high-RPM engine? Present day designs are happy on an oil viscosity of 10 to 15 cSt. (But many are OK on less than 10.) 30cSt is too high at high RPM. It can lead to foaming, air entrainment and cavitation. Temp. for 30cSt (DegC)..........Temp. for 15cSt ............Temp. for 10cSt 5W/40.........71.............................90.................................117 10W/40.......70.............................99.................................118 10W/50.......80............................109................................130 10W/60.......89............................119................................142 As you will see from the above table a 5W/40 or a 10W/40 is perfectly adequate for all engines except those that run unusually high temperatures (120degC plus) Cheers The Opie Oils Team Quote Link to comment Share on other sites More sharing options...
Gerhard Posted August 14, 2009 Share Posted August 14, 2009 Efter det där så är inte 40 oljorna lika tjocka vid 100°? Quote Link to comment Share on other sites More sharing options...
kimmen Posted August 16, 2009 Share Posted August 16, 2009 Efter det där så är inte 40 oljorna lika tjocka vid 100°? Ser mer ut som om 120 grader skulle vara mer rätt..? Ja, man lär sig olika på olika ställen. Quote Link to comment Share on other sites More sharing options...
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