im not sure but shouldnt my NA have two catalytic converters? one right off the exhaust manifold then the one near the middle of the car with a pipe that leads back to the 5th and 6th ports? well mine only has the one in the middle. reason im asking is id like to make damn sure my 5th/6th ports are opening fully at wide open throttle. on ebay i found a magnaflow bolt on from the manifold to the center with a cat for around 100 bucks free shipping.

Ive heard people can just stick the 5th/6ths open which sounds like the easier and cheaper route but what could i expect as far as bottom end power and fuel economy? leaving the ports open all the time id loose intake velocity and fuel economy am i right? i dont like loosing fuel economy. also im premixing my fuel with twostroke right now and dont plan to stop, its just really good insurance to do so, which in turn can destroy catalysts right? any other thoughts? my mission here is not clean exhaust emissions but only to get my 5th and 6ths working properly.

 

There's a writeup in the archive about how to use the air pump to actuate the 5/6th ports without catalytic converters.

Don't wire them open. The car won't accelerate worth a ****.

And it should have 3 cats actually.

 

the 6 ports only take about 2-2.5psi to open, which means that they should be opening with a stock main cat....

you can always put a pressure/boost gauge in the 6 port hose and check

 

ok question, do these cars have 3 cats to keep the exhaust from smelling? cause my cars smells like raw fuel all the time. wow smog pump will do that? haha! sweet let me go check it out!

 

just read the article and thats the way im gonna do it, thanks so much!

 

3 cats because 1980s technology for catalytic converters wasn't the greatest. One was a pre-cat, one was a main cat, and..

I really don't know what they all were to tell you the truth. All I know is that a single catalytic converter by today's standards can rock the world of all 3 OEM FC cats.

 

I ran a S4 with a full exhaust (MT header, Bonez cat, RB mufflers) and it actuated just fine. As long as your actuators are in good shape and you have a remotely reasonable exhaust they'll work fine.
My current S4 has the actuators wired open, because the stock actuators don't open the ports all the way and I was chasing a slight HP advantage around redline. Power suffers a bit below 3000RPM and cruise mileage is down to 20MPG, but it has a strong surge from 5000RPM to 7500RPM.

 

Just do the airpump activation.

I literally wrote this post just a few minutes ago: https://www.rx7club.com/2nd-generati.../#post11305596

 

Fuel economy will be horrible. I believe mine went from ~23mpg to about 12mpg. Acceleration at low rpm is nil. Noticeable power gains at the higher end rpm's, tho.....a blast to drive on the highway versus non-working ports.

 

 

great info thanks, ill keep the exhaust with the catalytic converter then use the grease trick and check if the actuators are working on there own. the rear one moves easily if pressed down on but the front didnt. upon inspection i found one of the screws is missing so it was binding. looking forward to getting this thing put back together and feeling the difference.