I’ve decided to remove as much emissions equipment as possible on my NA S5 while doing a rebuild. It’s my understanding that it’s safe to remove the EGR valve, catalytic converter, split air pipe, and solenoid rack with some modification to some vacuum lines.

I’ve read that the S5s have their 5th/6th port actuators ran from air pump pressure, so the air pump has to remain in tact. However, I’m somewhat foggy on what I’m able to do with the ACV and how it works. Since it sends air to the cat, if I remove the cat do I need to install a block off plate somewhere? Do I even need the ACV at all? And, just to make sure, am I safe to remove the entire solenoid rack and still have my 5th/6th ports work? Thanks for any help, sorry for the long post. Somewhat new to this, so trying to gather as much information as possible.

 

ACV isn't necessary to actuate the 5th and 6th ports, there is a vacuum solenoid on the rack for that. You will however need to reroute the air supply lines for the ports if the ACV is gone.

 

there is no EGR on an S5...

the 6 ports and VDI use pressure from the air pump air to open, and they are switched with solenoids, so if you remove the solenoids for the VDI and the 6 Ports, then they will not work.

i know it seems cool to remove all that stuff, but in reality its easier just to leave the whole rack alone and just put it back on. it takes more effort to figure out what to keep and then it isn't as tidy as just using the stock vacuum rack

 

Thanks for the replies. Didn’t realize the S5s didn’t come with an EGR, as I read a write up that covers all 2nd gen models. If there’s no way to run the 5th/6th ports properly without the solenoid rack then I’ll hold onto it, was looking forward to the added cleanliness/simplicity. Thanks for the info.

 

Is there any possible way to remove the solenoid rack and still have the air pump/port actuators work? I’m in this project for the long haul, and would really like to clean these things up while I have the engine removed for rebuilding.

 

sure, the system is really simple, Mazda takes the high pressure air from the air pump (its physically in the ACV) runs it to the solenoid and then back to the actuators, you could totally duplicate that without the rack

in fact that is how all of that stuff on the rack works, except everything else is using vacuum and not pressure