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-   2nd Generation Specific (1986-1992) (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/)
-   -   does my mechanic know wtf hes talking about (https://www.rx7club.com/2nd-generation-specific-1986-1992-17/does-my-mechanic-know-wtf-hes-talking-about-99863/)

wpgrexx 07-26-02 11:21 AM

does my mechanic know wtf hes talking about
 
lets see, i'm about to port the manifold and clean the ports. i hadf dual exhaust put in my car almost 2 summers ago. he removed the air pump. the ports were stuck so i freed them and wired them open. now that i am gonna take it apart i was looking at better ways of actuating the ports, noticing that there is a line coming of the exhaust going to underneath the ports i decided to go ask them what this was all about.

Now i have read that at 3800 they need something like 1.8 psi to start opening and at 5000 they need 2.1 to fully open. the mechanic said that the hose they put running from the exhaust goes straight to the ports and has enough pressure to open them. when i asked him about the numbers(2.1 psi) he said all you need is a little blow, he also said that the air pump had nothing to do with the ports and there is absolutely no reason in the world that i would want it if i don't have cats. he said if i clean the ports they should work perfectly.

sorry for the length but i need to know if this guy is feeding me a line or not. they are very reputable and did a beautiful job on the piping so maybe they aren't that dumb!

HAILERS 07-26-02 11:27 AM

Airpump has nothing to do with opening the auxillary ports on a 86 model. Backpressure from the exaust has everything to do with opening them. He's ok.

Bambam7 07-26-02 12:27 PM

Sounds right to me- if it's the 86 model in your profile you are talking about.

The Mazdatrix and RB exhausts come with the backpressure tube for the aux ports- exact same thing.

Bambam7 07-26-02 12:38 PM

Sounds right to me- if it's the 86 model in your profile you are talking about.

The Mazdatrix and RB exhausts come with the backpressure tube for the aux ports- exact same thing.

hypntyz7 07-26-02 12:38 PM

YEs he is exactly right on all counts.

GOt an air compressor and a gauge? Adjust flow to 2.1psi and then feel what is coming out...that is a very small amount of pressure, really.The engine is an air pump too, a compreswsor if you will, so the exahust can generate that too.

That said, I dont like the stock 86-88 exhaust-actuated system worth a shit. I posted instructions on how to build a fully electronic 6 port system on a thread about how to clean 6 ports or something not long ago...search for that and you might be interested. THe way I wrote it requires use of the air pump...you can also search the junkyards for a car that had electric smog pumps on it(cadillac comes to mind) and use it as part of the electronic 6pi system.

Supermac 7 07-26-02 12:59 PM

Everyone is right, listen to your mechanic :) seems like he knows what he's talkin about.

wpgrexx 07-26-02 02:14 PM

wicked. that is great news. i took off the wires today and drove it, but i don't think they are working because of dirt buildup. the car felt a little quicker above 4500 with them wired open. then again the fact that it is 32 degrees celsius plus a retarded humidity it is probably closer to 40 degrees.

Yesterday i got gaskets #
n32613112a
n32613111a

i hope these are the only ones i need to port the intake

today i got some "pretty" blue silicon high temp vacuum hoses and a bottle of watter wetter. next i am gonna call pineapple and order some sleeves for 5 & 6 ports. when i have everything all apart i am gonna do a crazy cleaning under the hood, i also am going to actually take the ps pump out and fix the lines instead of just no belt. possibly will redo my cold air box.

does anyone know of any certain brands of insulating heat tape to further cool intake charge?


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