I had been in a discussion with American Jebus about this a while back and I about got my head ripped off by some other people on the subject.
Here is what you should be looking at for reference on a car with NO modifications made that increase oil capacity:
Also understand that the DRY FILL and REFILL numbers are NOT the same!
Dry fill refers to filling a truely dry engine (newly assembled or reassembled engine with NO previous oil run through it after assembed)
Refill refers to a true refill (an engine that has had oil run through it after assembly or reassembly)
Oil does stay in the engine attached to parts of the motor, the walls of the pan and passages in the block, the rods,inside bearing grooves, inside the cam housing of the head, etc. and (weather you believe it or not) it does accumulate to the difference in dry fill and refill capacity amount numbers.
Do not use any amount of oil over the factory recommendation on a refill unless you have somehow modified the oil capacity of the engine and CAN AND DO DRAIN THE ADDED EXTRA AMOUNT OF OIL OUT at the time of a change. This means that if you are running a larger capacity oil pan or a custom oil cooler of some sort, you MUST drain the oil from the cooler lines, the cooler and of course the pan if you plan on refilling the engine with the additional custom oil amount.
You do not have to drain the added amount of oil out of a cooler or the lines at a change, but know that the added oil capacity that remains in the cooler and lines once the rest of the oil has been drained is not to be added back in upon refill.
This actually doesn't affect your oil fill level on the dipstick because ANY additional oil in a custom capacity situation (coolers, accumulator or custom pan) should never fill the oil past the full level marked on the dip stick.
If you overfill an oil pan, you risk having the oil make additional unwanted contact with the crank shaft (known as windage) on acceleration, cornering and braking when the oil moves within the pan. This causes the crankshaft to whip air into the oil contacting the crankshaft and foaming occurs. The problem does NOT occur at idle when the oil is level. It happens when the vehicle is in motion and windage actually occurs even a small amount with the factory recommended refill amount/level.
In all honesty, the lower your fill level is, the lesser chances you have of creating windage in your crank case. The only way you can decrease oil level and keep or increase capacity is to run a custom oil pan and or some other form of oil accumulator tank or cooler. Running a deeper pan is usually not a good idea on a street car because of ground clearance issues, but there are other ways around it.
What ever you do, do NOT over fill your pan for any capacative reasons. The additional oil capacity is NOT worth the raised amount of level and windage. Although oil does get consumed between changes (even in perfect conditions) you should only add additional oil WHEN IT'S NEEDED and not retro-actively before the consumption has occured. It will only aid in oil consumption by overfilling the level.
I do agree that more capacity is better, especially on a turbocharged engine, but you do NOT simply add more oil to prevent a potential starvation problem. Modify your oil capacity the right way or leave as close to the recommended factory full level. If you need more capacity for your turbo's needs, you should modify your oiling system and capacity accordingly and correctly.
When it comes to an unmodified system on a vehicle, I will not argue the recommendations made by the engineers that designed the system.
These are my reasons for being with American Jebus 100% on the subject.
