Quote Originally Posted by pepi View Post
"I have a couple projects that i need to replace those electric vacuum pump systems i have tinked and dinked on those things from the day i installed them. They are poorly engineered, overrated, noisy, cumbersome - you name it. A poor solution to a problem and the sooner i get them into the trash the safer the car will be.
I'll continue looking into the operating range change of the booster and will let you guys know what i find.
Thanks for all the replies, it looks like the hydrosystem is the way to go."


I disagree, I have run one for 12 years without so much as a hick cup and the car is on the road every weekend, is not a garage queen. You do get what you pay for I will say that. For my application a hydrosystem with all the hoses, the size of the power steering pump would look out of place and junky. The electric pump in out of the way and hidden, my motor is exposed to the world not buried under a hood and fenders. I will bet my next paycheck you will not find a way to adjust the operating range of the booster . Will not be holding my breath waiting for that answer.
You're right, i have spoken with a couple booster rebuilding shops and you can't change the vacuum requirements, it is a 'per square inch' kind of thing.
As far as the electric vacuum pump, similiar to what stainless steel brakes sells, i have installed several. To date three have failed for different reasons and i now keep spare parts in stock - esp the vacuum switch. I believe the oldest unit is 4years old? maybe. I am trying to find a better system. As far as i am concerned with properly designed 4wheel disc brakes you don't need power assist, it is a drivers preferance kind of thing unless you have a physical problem with your hips for example.
It would be nice if we had a ton of space and could have about a 8:1 pedal ratio and do away with all the 'add-on' stuff to reduce pedal effort. I have even made toggle cams Between the pedal and the booster) to change the ratio in cases where i could get only 5ish:1 pedal ratio.
Here is the level of effort difference (in case you are wondering), for an aggressive stop - not panic - it takes about 75lbs of leg effort for mechanical and 50lbs for power assist. They both equal the same amount of force at the caliper/drum. The caliper/drum works at about 1200psi because of the hydraulic seals, so that power assist can't stop quicker it is just easier to get there.
I didn't mean to get into engineering gobbeldygook but maybe somebody will find it interesting.