Alright, what is the difference between a 4-port and a 6-port motor? Well, obviously the number of ports, but is there a big performance difference, and which ones came on which models? The reason I'm asking is the RB Exhaust Port templates are for "All 13B except 6-port". Anyways...yeah...

 

That question has been asked before.I think its in the engine building and porting forum.

 

4 port == turbo 13b

6 port == NA 13b



of course, this means in stock form, people have turbo'd 6 ports and NA'd 4 ports, but thats modded.



not sure on performance difference, as far as the end housings go, in stock form the 6 ports have more timing when aux ports are open, so i guess there is potential for more power there if you turbo it, especially with working aux ports it might help low end torque.



most people use 4 port motors in their buildups though.

 

the 4 port is easier to get power out of.

the 6 ports came in 84-85 gsl-se, and the 86-91na cars.

in japan they also had a 6 port 12a for the 81-82 rx7 and 929's.

4 ports came in everything else



mike

 

4 port 6 port, *** all that, just go bridge port :yum:

 

Bridgeports rule but 6 ports are cool.





Then there is the 6 port bridge.. The best of both worlds?



6 ports have more intake timing and some pretty decent ports. Bottom end suffers without the sleves, but in stock form a 6 port has more power than a 4 port (N/A Trim). More people modify 4 port engines, doing street ports, bridgeports, etc.