vacuum brakes
 

has anyone tried to add a vacuum tank for EOC with power brakes?

I don't know about your cars, but I get a good three pumps on my brakes before I'm out of vacuum. This is enough vacuum 99% of the time. Plus, part of ecodriving is not using your brakes. ;)

i have one 5% grade for three miles speed limit 30mph and one 6+ % speed limit 55 hard with an auto

Is it possible to (safely) shift the auto into a lower range and have it stay there while you go down the hills? Then you might not need brakes.

no i have to neutral to turn off and stop the motor then urn back on for speed and odometer.

i could idle in a lower gear but its a 3.8 liter engine lots of gas just to do that

I take it your plan is add an additional volume to hold vacuum (sic) and plumb it in between the brake booster and the checkvalve in the brake booster line. For example if you had an big propane tank which you emptied, unscrewed the valve, cleaned out the oil that will be on the bottom, etc. you would use this as the tank. It sounds reasonable.

The down side of this is that it would take LONGER for the engine to establish a new vaccum if you used it all up while the engine was off. But if you plan ahead it could be OK. And it is better than no power brakes at all.

just to add, I think the vacuum is only used while you are changing the position of the brake pedal. If you keep the brakes pressed the same amount and don't move the pedal I don't think you lose the vacuum.

yeah i guess i'll see what i can find for a tank, go from there. thanks for you thoughts on this

For long grades like that you can always use the e-brake for small amounts of braking so you don't use up your vacuum.