Straight newbie question. Why do some manifolds curve up then down? Better air flow or something? IDUNNO

 

It's to keep the length of each primary runner the same length. There is only so low you can go with turbo location. This is because the turbo depends on gravity to drain the oil out. Therefore the turbo must remain higher than the oil level inside the oil pan.

 

i thought it was so that all the exhaust gases reach the turbo at the same time, so that it flows better or something, just a guess. i didn't know it had anything to do with oil drain on the turbo.

 

Well you are right. My point was that you could make an equal length manifold that didnt rise above the exhuast ports at all, but then you would have problems draining the oil. The designs that bend up and above the exhaust ports do so, in part because the drain on the turbo needs to be located above the oil level.

 

the less bends..... the better