how hard is it to drill into a cast iron block anyways?

 

this site has become so backasswards...



you can drain anywhere in the pan. there is no significant drain from the turbo that will cause cavitation or any of this bullshit.

you think oil is going to become anti-gravity and suddenly go up your drain and back into the turbo? yes, there may be a slight amount in the turbo drain, but it will not go any higher than what the oil level will be inside the oil pan.

 

Not true.

Though it doesn't "flow" up your tube, there is volumetric constriction.

Have you ever filled an auto tranny? If so, you would know that the ATF will easily back up the dipstick fill tube, and all over your motor, because there is simply too much of a volume of liquid flowing into that tube, to effectively drain with the same speed to which it was filled.

When the car isn't running, your statement reigns true. But what happens once your car starts pumping oil into the turbo?

Even with 1/8th inch lines, there is a LOT of pressure going to the turbocharger. Without a proper, free flowing draiback, your turbo would fill with oil, pressurize, and blow oil out the seals. Not because it had weak seals, but because they merely aren't made to hold much pressure. If you ever take a turbo apart, you will notice there are oil reliefs and extra drainback slots cast into the center housing. If any one of those reliefs get cooked with oil (a symptom of premature shutdown) it will begin to pressuize the turbo, causing seal blow out.

If you notice, most factory turbo cars (and ALL the turbo cars I have seen) have a drainback in the block, ABOVE the oilpan and nearly parallel to the crank centerline. Why?

Because then there will never be oil sitting in the drainback, that has to free flow out the end of the tube, which could be as low as the bottom of the pan.