patricklav

iTrader: (7)

Hello,
I am running a big cam in my sbc350 and have about 10" vacuum at idle. When I slam the brakes I get sloppy results as the booster is hard to push. I currently have the vacuum port on back of the carb (holley 750) connected to a vacuum can and then to the brake booster. I'm thinking of adding an electrical vacuum pump to add vacuum and assist in my braking.

Rather than spending $300 for an aftermarket vacuum pump is there any stock equipment that I can use?

I've checked on Ebay and seen vacuum pumps from a Chevy Cruze for short money ($80). Looks like it runs off a relayed 12 volts and should provide plenty of vacuum. Anybody have any ideas on whether this would work?

thanks for the help

sofakingdom

iTrader: (1)

Lots of the old car and light-truck diesels used to use those too.

Another option would be a hydroboost; gets its power from the power steering pump. Chevy trucks have ALL been using that since the early 00s, and lots of other vehicles before that.

Lurbie

iTrader: (3)

Many GM cars have an electric Auxiliary Vacuum Pump. Certain HHRs, Solstice/Sky, 5th Gen Camaros, etc. They'll also have the one-way check valve in the hoses already, so be sure to grab that also. They're all relay controlled 12v motors, but in the OE operation the cars usually have a vacuum pressure sensor and only run when needed. You could still rig something up to make it work only when necessary. That's what I plan to do when I get my motor together, but that's a year or so down the road for me.

patricklav

iTrader: (7)

Thanks for the replies guys. Sounds like the Cruze pump will work. I was thinking of wiring the relay to my brake light so when I hit the brakes the pump activates. Obviously there will be a slight delay before I get full boost but this will definitely help if I'm in traffic or parking. I'm open to any other ideas as well.

I'm going to check into the hydroboost option as well to see if it's a Berger option.
Thanks again.

Base91

iTrader: (1)

There are a bunch of threads on the hydroboost using the parts from certain year Astro vans and someone makes a complete bolt in set up but it's something like $600 or more. I've been thinking about an electrical vacuum pump and reservoir too. I like the idea of moving PCV vacuum to the reservoir system as well and using manifold vacuum only for engine control. Just seems like it would be better that way.

Lurbie

iTrader: (3)

I would strongly encourage a relay and a vacuum switch to control the pump. There seems to be several options, but here's a couple I found doing a quick search on Google.

http://www.evsource.com/tls_braking_system.php
(Scroll down to the vacuum switch)
http://www.evwest.com/catalog/produc...roducts_id=290
(maybe I'm wrong, but seems this switch has a pretty high vacuum setting)

Lurbie

iTrader: (3)

Here's another one from Summit, cheaper than the other 2 links I posted earlier today.

http://www.summitracing.com/parts/ssb-28146sw

Just be sure to use a relay, let the switch control the relay. The relay will control your pump. I also read a Hot Rod article that talked about adding an oil pressure switch (kind of like what's done on our fuel pumps) that would prevent the pump from running with Ignition on and engine off. Not sure I'd waste the time and money on that, but if you don't want the pump running until your engine is running, that's a good way around that too.

patricklav

iTrader: (7)

thanks for the replies Guys. Think im going to go with the SBBC and the valve.

//<86TA>\\

iTrader: (15)

I bought a vacuum pump off ebay from an industrial application, think off a earth mover or some th ing. Then got an adjustable n/o vacuum control switch to wire in the circuit so it o ly runs when thr key is on and shuts off at whatever setting I have it at, which I think is 25 inches.

Pump was 125 and switch was 25