No Need For Vacuum Pump
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
No Need For Vacuum Pump
About a year ago I installed a Competition Cam's 236/236 degree Magnum cam in my 454" and right away I had no more than a single brake application at idling speeds in city traffic. As an experiment I drilled and tapped the front of my booster for 1/8" NPT threads, screwed a 1/8" X 90 degree brass elbow and 3/8" steel nipple into the booster, then connected it to my vacuum tank to increase the booster's volume by about 1000%. Once the vacuum tank gets filled it'll give me about 12-15 brake applications at idle speeds and it only takes a momentary speed of 20-25 mph to fully recharge the tank. So I found out there is another way of solving the problem other than using an expensive vacuum pump.
Safety Car
Joined: Oct 2007
Posts: 3,729
Likes: 267
From: Austin Texas
Corvette of the Year Winner 2017
2016 C3 of Year Finalist
except when you develop an unexpected vacuum leak, any where in the car
and your reservoir will no longer hold vacuum, your back to almost no brakes.
... and any component/hose connected to the reservoir tank that may fail/leak.
that's why the factory does not run the PB Booster off the vacuum reservoir tank.
GM did not want a convenience vacuum failure,= (wipers, headlights, A/C)
to reduce brake safety capability.
you cam specs are not that aggressive, you should be pulling good vacuum with that Cam.
what is your base vacuum at Idle ? ... with everything vacuum related removed.
you sure, .... you do Not have any vacuum leaks ?
and your reservoir will no longer hold vacuum, your back to almost no brakes.
... and any component/hose connected to the reservoir tank that may fail/leak.
that's why the factory does not run the PB Booster off the vacuum reservoir tank.
GM did not want a convenience vacuum failure,= (wipers, headlights, A/C)
to reduce brake safety capability.
you cam specs are not that aggressive, you should be pulling good vacuum with that Cam.
what is your base vacuum at Idle ? ... with everything vacuum related removed.
you sure, .... you do Not have any vacuum leaks ?
Thread Starter
Melting Slicks
Joined: Apr 2009
Posts: 2,632
Likes: 112
From: Great Plains Iowa
Yeah, its at .050" lift and it only pulls 5" Hg at idle in Drive. With it teed into my vacuum tank I have about 1000% more available vacuum volume to my booster at all times. Idling along in city traffic I never run out of power brakes because just a brief acceleration to 20-25 mph will fully recharge the vacuum tank.
And speaking about boosters I just replaced mine with an AC Delco "rebuild" that wasn't a rebuild at all but rather a new Chinese-made booster that came unpainted and the whole surface slimy with oil. It took me a full 7 hours of rework time just to make it usable so if you need a rebuilt booster stay away from AC Delco rebuilds. As it came from the Parts Boss in New York and I live in California and I needed my car I just did the necessary modifications. And besides that it only cost $87 with the $10 core charge included in the price.
