Supra Forums banner
1 - 20 of 168 Posts

·
Carma Performance
Joined
·
764 Posts
Discussion Starter · #1 · (Edited)
It has been a very common rumor on here for a long time that the 1JZ head flows better than the 2JZ. This has lead to alot of people doing the 1.5JZ swap or atleast wanting to. Over the last few weeks I have been building a 1JZ, including porting the head, for a customer. I flowed the head on our SF-600 flow bench before and after I ported the head.

A stock 2JZ flows about 238in and 154ex at .400 lift. A stock 1JZ head flows 215in and 133ex at .400 lift. After I did a good street port job including reworking the chamber the 1JZ head flowed 230in and 152ex at .400. This should put to rest the idea that the 1JZ head is better than the 2JZ, because the fact of the matter is that it is not better.

Erin
 

·
Republican
Joined
·
8,421 Posts
wow... finaly... the truth comes out!
 

·
Sir Digby Chicken Ceasar
Joined
·
522 Posts
When they say flows better are they saying flows more or as a ratio. Or does that even matter
 

·
Registered
Joined
·
939 Posts
Good info. Too bad I sold the 2J head that came with my 2J block! Oops! Oh well the VCs and the intake were already polished and everything so a little head work will get me back on track!
Cary
 

·
Registered
Joined
·
46 Posts
i heard that it was because the 2J had the runners on cylinder 1, 2, 5, & 6 leading to the valves slanted and the 1j had them all lined up straight letting the air come in quicker. naoto from blast racing told me this. dono how right he is
 

·
Check Your Face!!!
Joined
·
1,417 Posts
so maybe the 1jz just has better port velocity rather then better flow then, hmmm i wonder if there are any more tests that can be done for more information between the two heads.
 

·
Carma Performance
Joined
·
764 Posts
Discussion Starter · #17 · (Edited)
Saleen00_227 said:
i heard that it was because the 2J had the runners on cylinder 1, 2, 5, & 6 leading to the valves slanted and the 1j had them all lined up straight letting the air come in quicker. naoto from blast racing told me this. dono how right he is
This is not true. The port configuration is the same on a 1J as a 2J.


As far as velocity is concerned, it is true that port velocity is important but it takes a more expensive flow bench than I have access to to calculate. Velocity is dictated by the port size and there is very little difference in port size between the two heads. The difference being a slight difference in shape of the ports even though they are configure the same.

Dont get me wrong and think that Im bashing the 1j head, because Im not. It is just not as good as a 2J head by around 20cfm. Niether head is really that great of a head to begin with. It is way better than a 7M though :bigthumb:

Ill try to post some pics of the head I just finshed next to a ported 2J in the next few days.

Erin
 

·
1JZ BLING
Joined
·
2,604 Posts
can you put a 7m head on your flow bench and see what you get?
 
1 - 20 of 168 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.
Top