Originally posted by afm
Little bit confusing your question. Let's see 5 port engines have 2 side transfers and one boost transfer at the opposite end of exhaust port. The side transfers are divided in two by a bridge, so that makes 4 side transfers, plus the boost makes 5.
3 port engines have no dividing bridge on the sleeve side transfers, so that makes 2 side transfers plus boost transfer.
Now STS 3 port D3R engines have an aluminum bridge on the crankcase paths to both side transfers and boost transfer...and somehow aids mixtture flow simulating more ports. I haven't seen physically a 5 port crankcase to see if thy have them too.
I hope I'm clear on my explanation.
AFM
Sorry if I m confusing, let me explain again. Me and my friend have D5R, which is a 5 ports engine, which looks the exactly the same from the outside. However, upon inspecting the sleeves,they are both different. As I said earlier my sleeve looks like normal typical 5 port with both side 2 transfer port and 1 booster port, my friend's is like a Nova sleeve with both side 2 transfer ports (one vertical and one is normal horizontal) and the booster port has a divider or wall in the middle, which if you count will make 6 ports instead.