Why Powermaster?

[PSU 98]

Still looking for a GN, and every car I've looked at to this point has brake issues indicative of a failing Powermaster unit. So, why did GM use this system over traditional vacuum brakes anyway? I thought maybe the motor didn't produce sufficient vacuum, but plenty of people have retro-converted with no issues.

 

[turboc87gn]

Vacaum isnt the problem its when you are brake boosting the car the brake pedal will come back up at you and youll push thru the brakes...You also gotta remember how old these cars are..Gm prolly wasnt planning for things to work 20 years later and prolly didnt they would have the following they do

 

["Turbo-T"]

From what I've gathered, GM figured a turbo car might not always have the vacuum required to support the vacuum booster, so they went to a hydraulically power assist set up (aka hydroboost) from 1984 to 1985. Which was good HOWEVER the million dollar question is...why did they go from using power steering fluid under pressure...to brake fluid under pressure (aka powermaster)....to stop the car...?

I don't know either, but I'm sure they saw how it was a big failure, and after 2 years of use in the cars, it was all done for. Yet in an ironic twist, they decided to use the very same engine used on the powermaster equipped cars...to power the 20th anniversary Trans AM pace car, which was stopped by.....vacuum.

Chalk it up, GM has always done weird things that made no sense...such as putting a "fragile as glass" rear axle under an F body equipped with a 300 + hp LS series engine.

 

[SS/GN]

I don't know either, but I'm sure they saw how it was a big failure, and after 2 years of use in the cars, it was all done for. Yet in an ironic twist, they decided to use the very same engine used on the powermaster equipped cars...to power the 20th anniversary Trans AM pace car, which was stopped by.....vacuum.

Chalk it up, GM has always done weird things that made no sense...such as putting a "fragile as glass" rear axle under an F body equipped with a 300 + hp LS series engine.
__________________
Very well said

Kevin

 

[Nick Micale]

Since I have been dealing with Buicks longer than most, I received my information from the engineers at the GM proving ground in Mesa, AZ.

In the late 80's, they had a few GN's and a couple other turbo cars that were never produced, and they had many "mods" on these test mules.

I did some business with the facility and got to know engineers and tecnicians well.

When I asked why the "weird" brake assist unit on GN's, the PM, I was told it was a fore runner of the upcoming ABS units they were developing for various production cars.

Field testing was needed, and someone decided to put them limited production vehicles like the 86-7 GN's and mid-80's Regal station wagons.

This proved true, to me anyway, when the 1989 Cadillac came equipped with an ABS unit that is almost identical to our PM.

This is my story, and I am sticking with it unless someone can prove me wrong!

 

[turb0buick57]

Thats pretty sweet. Strange though that they would do field testing on production vehicles in the 80s. The powermaster has to be the most maintenance intensive braking system.