I've had the stock six port system with bolt ons. Then I added the pineapple sleeve inserts and it stopped working. I also switched from an RB cat replacement pipe to an RB header. Then I wired them open and it felt like it had decent high end power. Then I removed them entirely and ground out the LIM, removing the actuator rods. That's where I'm at now with it and it feels all around like garbage. My conclusion is that the stock working six port system is hard to beat on a stock port NA. I miss the torque down low but I can't tell if that was from the switch to the RB header or from taking out the six port sleeves. For anyone that's changed their six port system and added a header, let me know how you feel about the power differences and how it feels at low rpm vs. high, etc. Thanks.

 

A header should increase torque and power all across the power band. Especially on stock ports, I would rather have a working six port system. On a street ported engine, I would still choose a working six port system. On my own street ported engine, I have a working six port system and when those ports open up, it is very noticeable, even on stock exhaust.



So it sounds like you tried an experiment with intake design and are wondering if it was worth it. I wouldn't know, because I have never tried removing the actuators completely. One thing to remember about widening intake runners is that making them bigger will make the air moving through them go slower if the ports that they lead to are still kind of small. The runners were sized by Mazda engineers to get a somewhat best compromise situation of decent midrange torque and decent top end flow. Widening the runner by removing a restriction (six port actuator rod) could have an adverse effect by changing the speed of the air coming to the aux port at any given RPM, and throwing off the dynamics of the intake system.



But props for experimenting. I would like to make a custom intake manifold with six separate runners, one for each port. I just don't know when I am going to get around to it.

 

Its one of those things that I can't leave it alone. I opened a can of worms and in the end, I realize that stock is probably best. Maybe if I would tune the a/f ratio on a dyno somehow, I could get it to feel better but I'm not going through with that. Now I'm in need of some port sleeves and a stock lim is on the way.

 

our race car is no sleeves/rods too and it sucks ***! it feels like a turbo car with really bad lag, in fact it never comes on! a bone stock steel hood gxl is faster, my gsl-se is faster! keep the 6 ports working you loose so much down low i dont think it makes up for the 2-3hp up top

 

goin back! I need sleeves now.