Vacuum Question(s)

[G-boz]

Im running a Victor Jr intake with a Comp 292H cam and Im having trouble with my Power brakes. The Vic Jr doesnt have a vac port so Im pulling it off the carb, but still have weak brakes.
Just wondering if anyone else is running a similar setup and what can be done. Do I need to install a Vacuum pump/cansiter?

 

[LS6 Tommy]

If you're pulling less than 14" Hg at idle you're going to have problems. Most manufacturers say power brakes won't work right with less than 16". Try a vacuum reservoir with a check valve in the line from the carb, just like on the booster.

Tommy

 

[G-boz]

So the reservoire will store enough vaccum from the carb for the brakes?

 

[LS6 Tommy]

I can't gaurantee it, but it's a cheap thing to try.

Tommy

 

[malibu795]

244/244@ .050 and a 110LSA you idle vacum is prett low..

im runing a 234/244 @ .050 112LSA and hit 13-14" when warm at 850-900rpm

 

[G-boz]

Are you using any kind of vacuum pump for your brakes? I havent driven the car on the street yet, just been pulling it in and out of the shop.
How are you pulling vacuum for the power brakes? (intake, carb..)

 

[malibu795]

i use a 3/8" barb fiting off the back side of my edelbrock carb and run it straight to the MC booster

 

[G-boz]

So how is it driving on the street? Will the vacuum "pressure" rise after a higher RPM?

 

[Doober]

The port on the carb should be fine. I'm with Tommy & trying a vacuum reservoir if you don't want to change the engine combo. Far as vacuum rising/falling, there isn't any vacuum on acceleration, only time you would have vacuum is at cruise for the most part. You will also get a little extra on deceleration because the engine is under less of a load, and may actually be 'pushed' by the weight of the car if equipped with a manual, or the inertia of the torque converter if an auto is used.