Today i change my oil and oil filter only 41/2 quarts came out of the engine....the oil was full before the change!!! I thought the S2000 take 5.1 Quarts????

 

Some was left in the filter, some clinging to parts, and you may have been a hair low or not perfectly level when checking. Keep in mind that the dip stick is a very crude measuring device. Many of us have found that with a filter change it takes about 5.5 quarts to get back to full on the stick.

 

yep, same finding for me too, about 5.5 to get it at a nice full level on the stick. A lot of factors are involved including whether or not you drain it hot or cold, and then when you check the oil. Like cdelena said, it takes quite a bit (1/2 quart) to fill the filter up so you probably had about 5quarts in the motor which is fine..... unless you are saying it had 4 1/2 quarts when you dumped the filter oil into there too, which would mean you either burnt a little oil between the changes, or you didnt top it off enough the last time you changed the oil after the oil filled the filter completely.