I have replaced my main cat with a test pipe, and now thinking of ways to deal with my 5th 6th ports, wondering if i can cut off the bolting point for the split air pipe and drill a hole in my test pipe, and weld the mounting point to the test pipe and the everything will fit up OEM just with a test pipe instead of the main cat.


Will this create enough back pressure to open my ports? Or will this idea just fail?
Thanks, i did search, but only thing i come up with is people blocking off the ports, or usuing eletric pumps and what not.

 

There's no guarantee it will work, but that's essentially how it's done on RB's presilencer. I've used a straight pipe with a pick up welded on for the split air pipe, but there was never enough back pressure to move the actuators. Using smaller diameter tubing would be a better means of building enough pressure, as well as getting the inlet of the tube directly in the path of the exhaust.

 

Hmm, so basically if i want this to work i would have to make a custom smaller size split air pipe, and even then there is guarentee that it will work?
I guess i will be better off following Rotary Resurrection's guide on how open your ports with the air pump with no Cat.
http://www.rotaryresurrection.com/2n...actuation.html
Thanks for reply

 

I prefer my way: https://www.rx7club.com/2nd-generation-specific-1986-1992-17/activating-aux-ports-vdi-rpm-switches-907824/

 

the RB presilencers air tube opening actually points IN towards the exhaust, almost directly centered in the silencer, this is how they are able to keep the aux ports functional and operate at the same rpm as stock

any other high-flow cat or test pipe that has this air tube is not going to function the aux ports until later in the rpm band where exhaust pressure is greatest, as the tube is not in the direct flow of exhaust gases

 

That is a nice write up.
So either route i go i will have to partially block the ACV relief valve to prevent a large pressure drop, thus closing the ports.
Good to know.