Why half finned cylinders on 3.3 turbo motors?

[fastfredracing]

What do you suppose porsche was trying to accomplish with the half finned cylinders found on the 3.3 turbo motors? Were they trying to improve air flow around the jugs? .

[Strygaldwir]

My understanding was that it is to even the cooling around the entire cylinder. With flow directly on the top it was thought it would get disproportionally cooled on that side.

[proffighter]

My 2 cents:

There is much more heat at the exhaust side which leads to more extension there. So if you have fins there, cooling is improved and on the inlet side less, so you get a more even extension of the cylinder all around