Hey, so I hope this makes sense....

I have a 13b n/a from a 86 rx7 that I'm putting into my Volkswagen Ghia.. actually it's already in I'm just putting all the other stuff on. I was planning on having a custom exhaust built for it, but now I've been reading up about opening the 5th and 6th ports... so I'm looking for my best option here to get those to work.

I have read about the aquarium line method.. though I'm still a little bit in the dark about how this works... though it could be because I'm still learning about this motor. Is this the ideal solution?

I also see that the Racing Beat header would work, but I'm unsure if I can put this in my application.... I think that might go straight into one of the axles (as the engine is in the rear of the car)

I'd appreciate any help and information you might have.

 

wire them open? but that would not be functional.

 

^ and a massive loss in power is achieved by wiring them open.

 

that's a series 4 motor and operates the ports by exhaust backpressure, not by the air pump. what kind of exhaust setup are you trying to run? straight pipes, cats, mufflers, anything?

 

I'm not sure at all what exhaust set up I'm going to use... that's the advice I'm looking for... one that will still open the 5th and 6th ports. Here is a simple diagram some made of what the ywere planning to do plus two pics of another guy with the same car (though his 13b is supercharged).... As you will see there isn't a ton of room for the exhaust and I felt that if I went with that Racing Beat header to fix the 5th and 6th port problem it would end up in the axles which you can catch of glimpse of in the pics.... Also would a Super Trapp provide the needed bach pressure?

 

For this, you could really wire them open. The low end torque you'll end up with will still be above the original torque that the Ghia had with its original flat4. Just do the usual beef ups to that tranny.
As for the exhaust, any header meant for the original will need some custom tubing to spit it out(sides, rear). You could cut off the collector end, and weld it up the to the other side, and then patch up the other side. This way you still use the correct flanges to bolt up to the engine

Good luck on this project

 

Below is a pic of how I open my ports. It doesn't take much pressure to open the ports, 2.5-4 psi iirc. The copper line is 1/8" with a compression fitting going into the the tee. The line is about the right od. to fit inside the rubber line coming off the 6 port actuator line.

 

there was also a really cool setup i saw about a month ago where a guy got electri silenoids to open them and a rpm switch to activate them. i will see if i can find it, it would be perfect for what you need because then you can get whatever exhaust you need.

cool setup by the way

 

https://www.rx7club.com/showthread.p...solenoid+ports

there it is, i guess he is selling the setup to do it with all the parts needed.
hope this helps

 

Hmmm.. that copper tube setup seems like it may be the way to go... basically the same thing the Racing Beat header has on it. So basically with that set up there would always be enough back pressure coming off the exhaust to open them up...and maybe a value to adjust the pressure so it kicks in at the right RPM?

A few dumb questions on this as I'm new....

1. Will the Copper tubing stand up to the heat put out by the rotary exhaust?

2.Are the 5th and 6th ports activated by the same line? My understanding is that it's just the one tube I would need... but just want to make sure there aren't two.

 

ya its just one line, looking at that thread i posted got me interested in the electric solinoids

 

Yea... I read about the eletric solenoids, but I wondered if they might get damaged from the heat... I just want the simpliest solution possible and as I am going to have to weld exhaust pipes together anyway the tubing shouldn't be much more difficult... but I'd still like to hear any other opinions on this. I know I my VW I don't "need" the low end as much, but...hehe.. that doesn't mean I don't want it.... So I don't want to just wire them open...

 

in another thread he said he was using RB headers and they have held up to the heat fine after 6 months

 

in another thread he said he was using RB headers and they have held up to the heat fine after 6 months. Tell you what though, these things are hard to find on the internet. ive been searching since i posted that and havent found any yet
damn double post