OEM Electric Vacuum pumps (for power brakes)

[JeffMcKC]

Re: OEM Electric Vacuum pumps (for power brakes)

Bill I called Doc his pump will be just what you need I am sure.

[BangShiftChad]

Re: OEM Electric Vacuum pumps (for power brakes)

I would totally go for an electric unit and make it work, BUT the hydroboost is a killer setup. In most applications, they actually take up less space than a conventional booster and master, by a lot. They work really good, and the parts are all from trucks that last.

[seered]

Re: OEM Electric Vacuum pumps (for power brakes)

Fed Ex will have the pump on your doorstep saturday morning
You will be stopping on a dime!

[CDMBill]

Re: OEM Electric Vacuum pumps (for power brakes)

Thanks Doc! If I can't go fast at least I should be able to stop well given the enormous brakes I have on the car. Chad, the hydroboost was the ideal option but with the engine set back and the tall heads, the valve cover just misses the tiny little Ranger aluminum master cylinder I run. The 71 has a very wide flat booster which sits behind, not next to the cylinder head on a big block car and the hydroboost unit is fat in the wrong places to clear. I mocked one up and even assuming I could reclock it 180 degrees to move the accumulator cylinder, the casting still intrudes into the valve cover rail of the head. I've seen some angled aluminum blocks used on similar installs in small block cars but they have substantially more room than I do.

The unit I'm getting from Doc is very reputable and should be the perfect solution. I'll post pictures when its in and report back on the results.

[CDMBill]

Re: OEM Electric Vacuum pumps (for power brakes)

I posted this question in the EFI section but I thought I'd repeat the question here for a broader audience.

As you can read in the regular tech section I now have, thanks to James (SeeRed), a Master Power electric vacuum pump designed for power brake systems paired with engines that produce low vacuum at idle. Mine was around 9 inches at an idle speed of 1000-1100 and I anticpate it will be even lower when I start up the new combination in a week or so as the new cam has a narrower LSA, 109 vs. 112, so I'm expecting 7-8 inches of vacuum.

It appears that the Master Power unit is intended to be tee'd into the vacuum booster line between the manifold and the power brake booster, It is setup with a switch that turns the unit on when the vacuum signal falls below 12 inches, meaning it will run always at idle and at large throttle openings.

Currently I pull signal for the MAP sensor off a junction block that gets vacuum from the manifold via .375" vacuum hose that goes to block and out again on the other side. Two small ports feed the MAP sensor build into the EMS-Pro unit and the cowl mounted mechanical vacuum gauge.

Vacuum generated by the pump would play havoc with these I suspect as it would pull from those lines as it is currently configured. My thoughts are run a separate vacuum line for the gauge and MAP off of the plenum, or use some kind of check valve to isolate the vacuum pump form the junction block when it is running. I'm not sure how it would get a turn off signal unless manifold vacuum actually pulled the check ballback against the pumps own vacuum.

I obviously haven't got that idea completely sorted out yet in my feeble brain.

Ideas...suggestions... better yet, proven solutions?

[JeffMcKC]

Re: OEM Electric Vacuum pumps (for power brakes)

Bill is it just a sensing line ?
Not really being connected
I would think if it was a tee the pump would be just sucking in the intake not the booster because of least resistance.

[SpiderGearsMan]

Re: OEM Electric Vacuum pumps (for power brakes)

booster vacuum is manifold
so is map sensors
do like gm -combine the map sensor and the pcv valve

hydroboost is nice , but they leak .....and the aftermkt is REAL expensive

[CDMBill]

Re: OEM Electric Vacuum pumps (for power brakes)

Thanks to Jeff for pointing out the obvious. A quick read of the installation instructions from the MP site shows that their pump is designed to be the ONLY source of vacuum to the booster so the connection is straight forward and there is no issue regarding the MAP sensor as that and the vacuum guage will be the only connections to the plenum of the manifold.

I was making this harder than it was thinking the MP unit functions like the Cadillac 4.1 unit as an assist rather than the sole source of vacuum. I'll post back when it is installed and the car is running next week. (fingers crossed)

[JeffMcKC]

Re: OEM Electric Vacuum pumps (for power brakes)

<<<<<< Is a Master of the Obvious on other peoples stuff ;) See you in a Few Bill, if I am done.