I' ve got a '72 GS455 that has had some creative vacuum house rerouting over the past 32 years. The smog system was taken off the car, and it looks like some of the hoses left at the same time. The car was built for California, so it had the AIR Injection system which is now off the car. I have a GM service manual, but the underhood set up is very confusing. My air cleaner isn't hooked up to the vacuum system in areas either, so the ram air aspects probably aren't working. Does anyone have some advise for putting things back to stock, or at least for maximizing performance? A diagram of how things should look would be appreciated. It's complicated under there!! Thanks for your help.
What would be the most helpful in this situation is a Buick Assembly Manual. Should be a real good diagram of the hose routing in there. This book will set you back about $20-25 bucks, but is well worth the price. Hope this helps. Jim
MG, Those vacuum hoses have nothing to do with the funtioning of the ram air. One of them operates the air blending doors in the dual snorkels. All this does is preheat the air going to the carb for winter operation. It doesn't help performance to heat the air. If you want those doors to work, just connect one end of the temp sensor(inside air cleaner) to full manifold vacuum. The other end of the sensor goes to the vacuum motors in the snorkels(use a tee). Then just run a single hose to your distributor vacuum advance. Use either ported or manifold vacuum for this. The other stuff is pollution device hoses. You don't need any of this unless you are going concourse resto here.
I'm looking at doing away with the thermal vacuum switch, where would the hoses connect, that currently connect to the three ports go?
Agreed: that's actually part of my question....much of the emission controls on my car is gone...the EGR valve wasn't connected to anything, for example...
Scott, That was all part of the transmission controlled spark advance(pollution device). Eliminate all of it. Then run a single hose from your choice of vacuum (manifold or ported) to the distributor advance cannister.
