I just put on bonez superflow catalitic converters, and racing beat cat back. I got used to running straight off the exhaust manifold for about two weeks, and was dissapointed when i discovered that it felt like the exhaust was choking the engine at high rpm's. I don't know if this is just how it has to be or if i'm just not getting enough backpressure to open up my 5th&6th ports. Does anyone have any pictures that can help me find the rods that i'm supposed to put grease on to test the 5&6?
By the way, it's a 90' vert.
Thanks for any help you can give.

 

your airpump runs the 6 ports. no back pressure needed.

is your air pump still on?

 

I just installed a RB header and Mazdatrix high flow cat on my 90 vert and am very happy with the performance gains sorry to hear your gains are not as expected.

Your 5th & 6th ports are opened by the air pump not by back pressure if your car is a S5 1990.
The actuators that operated the 5th & 6th ports are located directly above the exhaust manifold. I worked mine with PB Blaster when I was installing my header they were a bit tight at first but loosened up over night.
You should take a look at the shop manual someone was nice enough to scan the entire thing and post it to the web so put it to good use it’s free.

 

The aux port sleeves themselves could be all grimmy. When I had my motor apart, I used Castrol Super clean (in the purple bottle) and it got them looking brand new and rotating smooth as ice.

 

thanks, i'll check out the manual and see what i come up with