What is a BONDI engine?

What is an ester based engine oil, and is it good for the S38 engine from the BMW E34 M5 ?

• For example i'm interested in the MOTUL 10W40 300V Chrono and/or 15W50 300V Competition , both fully-synthetic racing engine oils. http://www.motul.com.sg/product_line_up/4stroke/4stroke03.html I mean , i know that they are good but i want to know why , because i can't find more details. Then i ask in using them in the BMW E34 M5 (~1988-1995) , the S38b38 old school racing engine (~1993-1995) (more details about it , here http://answers.yahoo.com/question/index?qid=20101028055449AAOHqgW ) From what i understand, the recommended factory oil at that time was a semi synthetic oil , 15W40/50 from Wintershal.But some say , being an M engine , it should use the Castrol's trademark oil the 10W60 TWS oil (used in today's M engines ). But some say that this oil has done premature cam lobes wear on the s38 engine (something about being to thick for the full load engine oil temperature, only in track condition the 60 weight is said to be the best, for this engine). So i don't want to take that risk. I mean i think i'm 'safe' if i stay in factory recommended weight but also i want to take the advantages offered by today's full synthetic oils. So that's how i came up with those oils from Motul.Also the car beeing special to me , i want to take good care of it , especially the engine. I don't want to track the car, only long highway road trips, moderate climate conditions, to present running conditions. So, a rebuilt engine (with stock specs & tolerances) , will either of those 2 options from Motul will ensure the engine correct requirements ? Any imput is of great help. Thank you.

• Answer:

  This will help you understand why that thick oil is not necessary for a street driven car. Also why that first number is possibly the most important thing preventing start up engine wear. The second point the article makes is to use the thinnest oil which will maintain your oil pressure at operating temperature, it may take 50 or 60 weight oil but maybe 30 or 40 weight will do.