Huh!? Took my GSL-SE to an ex-employee of MazCare and he told me that you cannot port a 6 port 13b?? Please advise.

Thanks,
BBZ

 

What he meant to say is that there are no porting templates. Do a search on aaron cake, and check out project TINA. there's some good discusion on it in the canadian section.

 

Thanks dude! Err...or dudette....ummm....thanks Fellow Forum Member!

 

Dude. Trust me. Dude.

 

There *are* porting templates, I think.

Main problem is, beyond the fact that there's already practically too much port timing on the tertiary ports, the castings are rather thin. All you can really do without going extreme is smooth out how the window meets the housing surface, which doesn't add much timing. Again, not that it *needs* any more (closing) timing.

They apparently work rather well bridge ported.

 

mazdatrix has an FAQ on it. It can be done though, he may just not want to do it. The primaries can be opened up and the exhaust ports can be made larger. But you can't port as much as you can with 12a side plates.

 

Yeah, there are some 6 port templates out there. Lots of people port GSL-SE and NA 2nd gen engines.

Peejay, I believe air flows through four ports all the time, thus making the 5th and 6th ports secondaries. Then again, it could be argued that they really are tertiary ports if the TB has one butterfly that opens right from idle, while one or two others are still closed untill the throttle is depressed some 10% or so. Remember that the GSL-SE only had two large injectors, thus requiring 'some' air to flow through the side plates, even at idle. At least the large injectors are low impedance (as if that has anything to do with it).

Too bad I don't think I've ever seen an EGI dynamic chamber without its intake elbow installed, so I can't be totally sure whether GSL-SEs have secondaries only, or infact tertiaries.

 

The SE and 2nd gen N/A motors all have 3 throttle plates up top.The single primary feeds both primary ports in the center housing.
The 2 secondary throttles start to open at about 1/3 throttle.They feed the 4 secondary ports in the end housings.Before the lower intake, there are only 4 intake passages,like every other rotary.Right before the intake meets the block,the passages split in 2.At moderate speeds only the 3-4 secondary ports get air.Under adequate exhaust pressure,the 5-6 port acutuators open the rotary valves in the block and direct air through the 5-6 ports as well.Thus,all 4 secondary ports are flowing and the overall port timing is increased since the 5-6 ports are placed furthur into the intake cycle than the other ports.
So,basically at idle and cruise only the primaries flow(which is why the injectors are in the primary ports.
Above about 1/3 throttle,the 3-4 secondaries are mechanically open and the engine is behaving basically like a 4 port motor,excpet there is dynamic supercharging going on between the front and rear rotor due to the tuning of the intake manifold.
At higher revs/loads,the 5-6 ports open and you have all 6 ports flowing,much like a bridgeport going full bore.

With all that port volume,theres not much need to port it out,just clean up the passages and transitions as stated before.The best way to increase power is controlling when and how much the 5-6 ports open.

 

Not to split hairs or anything but it's really nothing like a bridge-port. 6 ports are like an extended port in that they increase port closing whereas bridge-ports increase port opening.

 

Hmmm...the previous owner put a pretty free flowing exhaust on the car. header, no cat, staight pipe to muffler. Guess I'll have to change it around to get some backpressure.

Time for exhaust shopping.

 

Backpressure is the devil. You're screwed! Kidding. Backpressure still sucks though.

 

Well the actuators for the 5th and 6th ports have been removed. :headscratch: So are they always open? Any forseable problems?

 

With actuators removed, they are always CLOSED. The diaphragms have springs in them that automatically close the '6'-ports when exhaust backpressure is below 2psi. For this reason, many here who don't want to run the Mazda system 'wire' them open or remove the actuators and turn the rods to the OPEN position.

If you're interested in an effective presilencer system that accommodates the Mazda design, Mazdatrix.com offers a backpressure feedback tube on their -SE specific presilencers. I use that system and it works great. HTH,

 

I didn't compose that last post well. The springs and all are gone. It seems they're always open. I'll try and grab pics later today. But my question is, will this hurt or help performance for reliablilty.

 

It is completely false that a 6-port motor is either difficult or not worth the trouble to port. 6-port motors *love* porting...it's just a little bit more tricky. Certainly you don't have any control over Intake Closing (IC) port timing on the secondary side, but it's already insanely late to begin with. IO (Intake Opening) and IC timing on the primary side is totally free, and IO is free on the secondary side. There is also plenty of material to work with where the real magic happens: in the port bowl. Not as much material as a 4-port, but enought to make *major* improvements. The only real "issue" is the tradeoff between leaving the auxiliary ports open full time or retaining the sleeves. But, compromise is what porting is all about...even on a 4-port motor.

A few years ago, I built a GSL-SE motor with essentially a "rally port" (max timing without a bridge), using Teflon inserts to form a radiused bowl for the auxiliary ports, sans sleeve. That motor was a monster! Never dyno'd it, but it did do a 14.7 in the quarter mile with the stock intake and stock exhaust (only a cat eplacement pipe between the stock exhaust manifold and stock cat-back) even while falling on it's face midtrack due to the stock fuel pump not able to keep up. What suprised me most about that motor is that it was not short on torque at the low end. My racing partner subsequently snapped the tranny output shaft by bogging a launch...on DOT tires.

Most of my porting experience has been with 6-port motors and I've never found the exercise unsatisfactory in terms of cost/benefit. Perhaps this is because I was under the guidance of Rob Golden at Pineapple Racing, who taught me many of his secrets (like how to encourage laminar flow on the inside radius of the port). I place the "couldn't/wouldn't/shouldn't port a 6-port" debate right up there with "synthetic oil isn't 'designed' to burn" and "peripheral port engines are unstreetable" arguments. All bullshit in my personal experience.

Anyway, here are some pics of the GSL-SE engine porting job:

Primary Side:



Secondary Side:

 

"Not to split hairs or anything but it's really nothing like a bridge-port. 6 ports are like an extended port in that they increase port closing whereas bridge-ports increase port opening"

You got me.I was generalizing, that at high speeds,all 4 secondary ports are flowing.

 

You can streetport a 6 port 13b. Been there, drove one last month. Pulled hard too!

 

They also make a SS header with a 6port provision tube. Much closer to the motor than all the way back to where the preslincers are.

 

The motor's porting is similar to Blake's photos.