1st Generation Specific (1979-1985) 1979-1985 Discussion including performance modifications and technical support sections

GSL-SE exhaust header question

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Old 03-30-03, 10:10 PM
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Chad Carson

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GSL-SE exhaust header question

My header has a provision for the 02 and the vac for the 6th port. My question is one the OEM exhaust the tube that came out of the main cat and ran back up to the motor split off into two close to the motor.

Now I know the small tube is for the 6 port but what is the larger tube?
I do have a pic if needed. For some reason I can not post pics on here.


So right now the SE is 3ft off the ground. I just put a Roadroad race header, dual presilencers, and a dual muffler. I have the 6port vac hooked up and the 02 sensor but tring to figure out the other tube.
She is also getting Tokico Blues, Eibach springs, racing beat front and rear sway bars, and a tri strut bar.
Old 03-30-03, 10:22 PM
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Chad Carson

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Help

Any Rotorheads able to help?
Old 03-30-03, 10:47 PM
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Yeah dude,

a little advice. (and i know this from experience).

The exhaust backpressure thing isnt going to actuate your 6th ports.

BUT, to answer your question, the other tube goes off to the ACV outlet, which, on a stock setup, would pump air into your cats. Dont ask me how this works, because i thought that the exhaust backpressure was supposed to go through this tube. *shrugs*.

Take them both off, they are useless. (providing you take off your air pump, and air control valve, this requires an ACV blockoff plate RTV'ed to the block).

For now, also take off your 6th port actuators and wire the 6th ports into the open (down) position. I am currently developing a way to actuate them mechanically off of the throttle or perhaps dizzy.

I hope this helps. If you have any more questions feel free to PM me.
Old 03-30-03, 10:59 PM
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Chad Carson

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Thanks

Originally posted by ioTus
Yeah dude,
a little advice. (and i know this from experience).
The exhaust backpressure thing isnt going to actuate your 6th ports.
BUT, to answer your question, the other tube goes off to the ACV outlet, which, on a stock setup, would pump air into your cats. Dont ask me how this works, because i thought that the exhaust backpressure was supposed to go through this tube. *shrugs*.
Take them both off, they are useless. (providing you take off your air pump, and air control valve, this requires an ACV blockoff plate RTV'ed to the block).
For now, also take off your 6th port actuators and wire the 6th ports into the open (down) position. I am currently developing a way to actuate them mechanically off of the throttle or perhaps dizzy.
I hope this helps. If you have any more questions feel free to PM me.
Thanks. I figured it had something to do with that but thought the exhaust pressure came up throught it.
O'well. And yes, I just put my ACV plate on (Had to wait for the paint to dry) As far as removing my 6th port Actuators I am not sure on this.
Since my header has the provision for the 6th ports I might leave it hooked up until I can do more research on it. When you finish the development post it on here.
Thanks
Old 03-30-03, 11:30 PM
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Well you can leave them hooked up, but you wont have any power above 4k. Even if you do, you would have twice as much w/ them wired open.

I have the 6th port provisions on mine as well. They dont work, trust me man. All the 2nd gen guru's hate them, as well as rotary tune shops. We all concur that exhaust backpressure is too inconsistant to open, in effect, the secondaires on your car.

The exhaust backpressure is different in every gear, and is greater under load. This means that the 6th ports are going to open varying ammounts, or maybe not at all!!!

With my design, one will simply press teh gas, and at 3.5k rpm the 2ndary ports will begin to open, and open more depending on how far the gas is pressed! This will make for quicker starts (the 6th ports will already be open when you drop the clutch, as oppposed to START opening when you drop it), better wide band power (the benefits of low end torque, plus WOT repsonse!), and make those 6th ports actually work!

In the mean time i suggest wiring them open, and just drive it around a bit to see what you think. Note, you will lose mass low end, but the high end should more than make up for it, trust me ;-)

~Geoff
Old 03-31-03, 01:11 AM
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Yeah, i just wired my sleeves open... too lazy to rip apart the intake to remove them, but what a difference this made, this was actually enough horsepower to noticeably tell i was amazed that a dollar mod (zip ties) could make this much power, i'd guess i got 15-30 horsepower out of a header and opening these sleeves... and most all of this power was because of opening those sleeves, a header without doing this and i noticed no difference at all.
Old 03-31-03, 07:23 AM
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my 6 ports were opening with the R/B dual system so I left them in
Old 03-31-03, 07:35 AM
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Originally posted by 2GSLSE
my 6 ports were opening with the R/B dual system so I left them in
ditto... wiring open your 6th ports loses some torque down low, and up high it just functions the exact same way as if they'd open normally.. They designed them to work that way, I figure they probably did it for a reason...
Old 03-31-03, 12:19 PM
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And i'm tellin you this for a reason too ;-)

Do what you want, but i'm just trying to help.

~Geoff
Old 03-31-03, 01:25 PM
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How often are you running at less than 4000 rpm?

Do you need power then?

Wire them open
Old 03-31-03, 03:04 PM
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Check them to make sure they even are opening, it's common for them to get stuck closed... mine did and i had to hammer them open.
Old 03-31-03, 04:55 PM
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Originally posted by hamster
How often are you running at less than 4000 rpm?

Do you need power then?

anytime I go from a start?
Old 03-31-03, 05:51 PM
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it seems to me that in any situation that one would need power, one would launch at around 4000 rpm. this is right around where the tires would break loose. After the launch you would want to stay in the power band, 3000-4000 rpm and up.

just an idea
Old 03-31-03, 07:31 PM
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does someone want to post pics on how to wire the sixth ports open and the real truth on if its better or not i acctually have a road race header coming from r/b and im gonna have a peice of pipe go from the header all the way back to the muffler is this an advantage???i know it will be loud, but some one please post the facts or pm me..thanx alot
Jon
Old 03-31-03, 09:29 PM
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That wont have enough backpressure to actuate the 6th ports.

Yes it actually does work (did you read my responses above? if not you really should), and to wire them open, you take off the actuators and... well... wire them open. with wire. in the open position....

Old 03-31-03, 10:35 PM
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Chad Carson

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Test

Does anyone have the steps for testing them?

Also can you tell more detail on wiring them open?

Could you just remove them all together?

Also ioTus can you post a pic of yours?
Old 04-01-03, 12:16 AM
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TESTING:
step 1)

Take some twisty ties, and twist them tightly around the actuator shafts, snug up against the bttom of the shaft. Press the shaft in to make sure they will go up, and then let it pull back out. It should take the twisty tie all the way to the top. Check to make sure the back is tight enough as well.

step 2) Go for a "spirited" drive, (rev it to 7500 rpm a few times)

step 3) check to see if the twisty ties have gone to the top of the actuator shaft. If it is at the top, they work acceptably. If they are part way, or at the bottom, they arent opening at all.

REMOVAL:
step 1)

Unbolt the 6th port actuators (highlighted in blue), using a 10mm socket or wrench

step 2)

take some zip ties, and zip tie the little swivel thing to the bottom, using the inner set of bolts as the place to zip tie it to.


This mod made so much difference, that after wiring them (and remvoing my 100lb subwoofers), made my car so fast that the faceplate of my cd player FLEW into my lap from acceleration. It has never done this before.

My mom has the digi camera, i'll take pics soon.

Last edited by ioTus; 04-01-03 at 12:20 AM.
Old 04-01-03, 01:05 AM
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Clean out the actuators,
Make sure they rotate fully and smoothly.
Use the GSL-SE Racing Beat exhaust with the 6 port tube.

Enjoy low end torque and high rpm power.

Wiring them open is only a band-aid for a problem somewhere in the system.
Old 04-01-03, 02:13 AM
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Dude, i've already said this.

i HAVE the rb system, w/ the 6th port tube.

IT DONT WORK RIGHT!!!!!
Old 04-01-03, 05:27 AM
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I have the RB header from Mazdatrix, and have both tubes hooked up, and it works perfectly, opening up the secondaries exactly when it should. I have to pass emissions so I need the air to the cat.

The small tube is to create back pressure to open the secondaries. The large tube is to pump air into the cat to help burn unburnt fuel under certain conditions. There are complete tests for the Air Control Valve(ACV) in the factory service manual.
Old 04-01-03, 07:37 AM
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If you want it to really scream:

https://www.rx7club.com/forum/showth...hreadid=169237
Old 04-01-03, 08:59 AM
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Pass emissions

Kevin,

This may be a dumb question, but with all of those mods you describe, will the car pass emissions if it still has a cat and a tube to the cat?
Old 04-01-03, 03:39 PM
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ok ill try that also guys does anyone have the first housing injector fuel line? mine is leaking BAD!!!! to the first injector.....any info?
Old 04-01-03, 06:20 PM
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I think some of you guys are suggesting that wiring the six ports open is always a good thing to do. My six ports open fully at around 3500rpms, so it would only hurt my low end to wire them, and not improve my high end.

I just think it's worth a try to get them to work as designed before you go wiring them up and losing your low end, which I use all the time (I don't start out dropping the clutch at 4000rpms all the time).
Old 04-01-03, 06:39 PM
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so what have we learned here in this thread?

if it ain't broke, don't fix it.

if is is broke, fix it cheap.




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