Originally posted by POWERBRAKEBOB
HI! GUYS! Well the hydroboost controversy continues. If a vacuum power brake unit would provide 1200psi when the manifold is in boost conditon instead of vacuum, Buick would have installed the same Delco boosters on all Regals, including turbocharged ones. Vacuum boosters need vacuum to work, no secret. They are rated to operate at 20" of vacuum. When vacuum drops to 15", the booster loses 40% of it's power. At 10" of vacuum, there is no boost over a manual brake system, due to the pedal ratio difference. We actually love those Delco boosters for BB Chevelle and 55 Chevy applications. They clear valve covers and are only 8 3/4" dia. They work well "with vacuum" on those cars. We are seeing guys stepping up the horsepower with 572 motors, Hemi's, giant camshafts, big blowers, overdrive transmissions, etc. The Hydroboost runs off of the power steering pump. Therefore, NO VACUUM IS INVOLVED! In the case of the Buick turbo cars, the pump is spinning faster as the RPM and the boost builds. The hydroboost can build up to 2000psi and lock the brakes even tighter with higher RPM. The car explodes off of the line at 10lbs of boost! It just works. Hydroboosts have been around 30 years and can stop 14,000 lb vehicles. The powermasters worked when they were new, but they use phenolic vanes in their pump, and they pump brake fluid, which has no lubricity. The vanes wear out, and then cannot generate the 2400 psi to the accumulotor. The pump runs continuouly, trying to reach the shut off point of the switch. It just wears itself out even faster. The basic powermaster is rebuildable, but the pump and switch assy are not rebuildable. We are installing Hydroboosts on all vehicles that have a pump, and even adding a pump to the motor to power others. The Hydroboost is compact, and is guaranteed to work. We were appointed as the only outside distributor (other than the automakers) by Bosch to retro fit hydroboosts to other v ehicles. They are viewable on our website at POWERBRAKESERVICES.COM Click on "company info" for photos.