HOW to add and control EGR to a Chevy SB

[racprops]

OK I have read a much as I can on using EGR, I am very interested in running it.

My problem is I want to add extra EGR in a 93 Chevy 350/383.

These use vacuum EGR Valves. The intake I have has two ports so I figure I can run two control valves and double the amount of EGR at max flow.

I also figure on two ideas on controlling these valves either an electric valve to change the amount of vacuum OR a pulsed valve that depending on a duty cycle can control how much EGR is fed to the engine.

ANY idea and advice is welcome.

Rich

[serialk11r]

EGR should be off at no load, high at medium load, and off at max load. You can get that with two valves, one that opens at max load and closes at 0, and vice versa in series. I'm not sure how actual vacuum EGR valves work, but that's the idea.

You would need to add spark advance if you increase EGR, or you may lose fuel economy.

[Piotrsko]

As they say on Hackaday: you can do the pulsed valve with a 555 timer but vacuum from somewhere on the intake might be easier.

[racprops]

As the EGR valves on these engines are vacuum controlled I am looking for ways to control them myself.

So I can chose when and how much EGR is added.

Rich