Nitrous porting
Thread Starter
Drifting
Joined: Aug 2017
Posts: 1,914
Likes: 358
From: Dayton, OH
Nitrous porting
Looking for information and experience with nitrous porting.
If I understand the concept it would apply to a PDSC or CSC as well.
The concept is like this, on a NA head the intake port and valve are somewhat larger than the exhausts. The ratio might be 2.165 to 1.6 = 35%. This is apropriate as the cylinder may not fill to full atmospheric pressure and the exhaust moves a lot more gas faster because it is hot and expanded plus the piston is pushing it out. On an 11:1 engine 11 parts out of 12 are forced out by the piston.
The situation is different for PDSC and CSC engines. At 1 bar or so of boost the cylinder has 2 times the oxygen of a NA engine so a considerably larger amount of expanded, hot gas needs to get through the exhaust valve and port.
Nitrous porting enlarges the exhaust port to allow that to happen.
If I understand the concept it would apply to a PDSC or CSC as well.
The concept is like this, on a NA head the intake port and valve are somewhat larger than the exhausts. The ratio might be 2.165 to 1.6 = 35%. This is apropriate as the cylinder may not fill to full atmospheric pressure and the exhaust moves a lot more gas faster because it is hot and expanded plus the piston is pushing it out. On an 11:1 engine 11 parts out of 12 are forced out by the piston.
The situation is different for PDSC and CSC engines. At 1 bar or so of boost the cylinder has 2 times the oxygen of a NA engine so a considerably larger amount of expanded, hot gas needs to get through the exhaust valve and port.
Nitrous porting enlarges the exhaust port to allow that to happen.
