vacuum pump help

[WP29440SE]

I am only pulling 5hg of vacuum in gear, and not even 10 at higher rpms. obviously its not enough to operate my PB booster to its full potential. any one have any experience with this vacuum pump? opinions?

http://www.ebay.com/itm/12-volt-ele...Parts_Accessories&hash=item4d1e2ae55e&vxp=mtr


I don't have 250 or 400 bucks to spend on some fancy race pump. I am looking for opinions on cheaper alternatives. this is just a cruising 74 charger with a 440, using a 284/480 cam and 750 edelbrock carb, no vacuum leaks. my timing and carb are dialed in , and the engine runs great. the brakes are all new and work the way they should outside of the low vacuum, but I don't like how hard I have to push the pedal.

thanks guys.

 

[Hemirunner]

If that combo won't make enough vacuum to run power brakes then somethings wrong.

 

[WP29440SE]

If that combo won't make enough vacuum to run power brakes then somethings wrong.

this is a fresh 440 inside and out, with around 500 miles on it. what could cause low vacuum besides the cam?

 

[Hemirunner]

A very rich mixture or low timing.

- - - Updated - - -

Is that the old MP cam or the new one?

 

[Cranky]

Did you degree in the cam? If everything else is right, the cam may be a bit retarded. It should pull more vac than that if it was timed right.

 

[WP29440SE]

it is actually a summit cam , of which I cant find on their website now. I just stuck it straight in. i do have somewhat of a rich condition. i guess i need to go out and play with the tuning and see if i can get the vacuum up. its just that it runs so good i hate to mess with it.

 

[Hemi Rebel]

Electric vacuum pumps are used on some cars from the factory. Chrysler uses them and when i worked for saab the v6 9-3 had them. 07 08 09 years. They can be mounted in out of the way places. Best bet would be to find one used. Even a quick ebay search for them resulted in outrageous prices

 

[Xp29h]

I ran into same problem! Low vacuum, with external pump still brakes not great. Removed pump brakes didn't change! Finally traced booster and mc from previous owner to wrong one for car. It was designed for a manual to power conversion. Geometry was wrong in the pedal, pushrod and bracket. Don't know if this is a possibility in your situation but something to think about! Good luck

 

[Propwash]

I run the CVR E.V.P., works great. Full power brakes all the time. I agree with these guys though, something in not quite right with your vacuum. I run a more aggressive cam than you, and run a tad more vacuum as well.

Anyways, if you're looking to go the boneyard route, a lot of mid 80's to early 90's GM cars had electric vacuum pumps (not all though), if you can find them. Also, like mentioned saab, volvo and a lot of volkswagens also use them.

 

[sleepar]

X? On the tune... find the sweet spot with the vacuum gauge on manifold vac port on the carb.. sometimes a leaking throttle plate will give you poor vacuum and an over ritch condition to compensate..... the vac advance pot could be leaking double and cripple check every thing maybe a tooth off on the timing gears will do the same thing....

 

[Green72Runner]

what is normal vacuum for these? This guy is in colorado and i now as altitude goes up engine vacuum goes down, here in Utah on other cars i am a full 5 inches lower than other guys at sea level