EJ20K ports VS. EJ25D, EJ251 and EJ22T ports
Posted: Thu Aug 20, 2009 12:03 am
I figured I'd take a few snaps of the various ports I have here in the garage. I was a bit suprised to see the difference in the EJ25D and the EJ20K. There are alot of posts stating they came from the same casting. They d not, but it is close.
Also keep in mind that the difference between the "D" and the "K"looks worse than it is. This is because most of the extra size on the EJ20K is at the port floor where air is moving the slowest.
It looks like I forgot to snap a pic, but the EJ20k gasket matches the ej20k port EXACTLY. The gasket is the exact size of the port. Keep that in mind when comparing the pics.
EJ20K gasket on EJ25D head. In this case a '98 Impreza 2.5RS. The top of the port is very close to the same contour as the "K". the bottom however, is not nearly as wide.
Factory "port match" on a EJ251. In this case a 2001 Impreza 2.5RS. Keep this pic in mind when looking at the following ones.
Factory EJ251 gasket (which is slightly bigger than the port) on the EJ20K heads. Notice that the gasket is virtually the sam size as the "K" port, making the EJ20K ports slightly bigger than the EJ251.
EJ20K gasket over an EJ22T gasket. Very large difference here, as expected.
Keep in mind these port sizes are not absolute. They do not denote flow, only suggest which ones may be more suited to a given flow rate goal. The port shapes and the camshafts also play a role in total flow capacity.
If there are any other combos youi would like to see, ask. I'll try to take pics and post them up. I will do a few of EJ20G heads in the next day or so after I get them back from the machine shop.
Also keep in mind that the difference between the "D" and the "K"looks worse than it is. This is because most of the extra size on the EJ20K is at the port floor where air is moving the slowest.
It looks like I forgot to snap a pic, but the EJ20k gasket matches the ej20k port EXACTLY. The gasket is the exact size of the port. Keep that in mind when comparing the pics.
EJ20K gasket on EJ25D head. In this case a '98 Impreza 2.5RS. The top of the port is very close to the same contour as the "K". the bottom however, is not nearly as wide.
Factory "port match" on a EJ251. In this case a 2001 Impreza 2.5RS. Keep this pic in mind when looking at the following ones.
Factory EJ251 gasket (which is slightly bigger than the port) on the EJ20K heads. Notice that the gasket is virtually the sam size as the "K" port, making the EJ20K ports slightly bigger than the EJ251.
EJ20K gasket over an EJ22T gasket. Very large difference here, as expected.
Keep in mind these port sizes are not absolute. They do not denote flow, only suggest which ones may be more suited to a given flow rate goal. The port shapes and the camshafts also play a role in total flow capacity.
If there are any other combos youi would like to see, ask. I'll try to take pics and post them up. I will do a few of EJ20G heads in the next day or so after I get them back from the machine shop.