Vacuum pump for power brake booster

for the "noisy" pump;  could a lot of it be the mounting?   tuned "spring" isolators

i litterally just purchased that pump and recieved  it yesterday.

thats where i ordered it from. maybe i over payed?

the only place i think it will fit on my car is the passenger rear splash gaurd.

im going to be installing it this today and tomorrow so ill let you know.

my engine only makes 7" of vac at idle so the guy that's tuning the car said i need one, but i haven't noticed an issue without it yet.

Dan

You might be able to install it without the black sheet metal housing around the actual pump. I think some people do it that way when it has to go into a more confined space.

Can you make a pic with Something next to it for size reference, please

it's 7" tall amd 7" from mount to outside

@Bell3156 posted:

it's 7" tall amd 7" from mount to outside

That should fit in the area where the horn is on the opposite side..

Some are using the Volvo pump from the diesel series. I don't know how quiet it is.

My Compcams pump is noisy but installed in the engine compartment behind the a/c compressor so it's noise gets lost a good extent by the noise of the engine.

It isn't on all of the time. It cycles and if you use it with a vacuum storage can it won't run as much.

Where to put it is as much of an issue as the noise. Possibly more?

it's pretty loud, a cheap one must be crazy . i'm mounting it to the passenger side splash had it has dynamat on it now

i have an original vaccum canister somehwere

@Bell3156 posted:

it's pretty loud, a cheap one must be crazy . i'm mounting it to the passenger side splash had it has dynamat on it now

i have an original vaccum canister somehwere

Which one are you referring to? They are all little compressors about the sound level of the original a/c compressors. You can route the output with a hose to the back of the car near the exhaust somewhere and put a lawn mower muffler on it.

Here is a sound clip of mine running.

Does it do that continuously?  Sounds like a wood chipper!

It shuts itself off, but each time you press on the brake pedal, it would come back on us

I tested the Bosch electric fuel pump that came with the car and it’s the opposite of the vacuum pump. It is quiet and not much vibration comes out of it.

It actually sounds cute… 🐥

Years ago I was working on a compressor product for instrumentation where excessive noise was an issue. I found that a good inlet muffler and good vibration isolation is key to noise suppression. Putting the pump into an isolation box works well but often not practical. There are many inlet noise suppressors available to choose from and they aren’t very expensive. I suggest using a short piece of vacuum rated rubber hose between the pump and suppressor. Vacuum rated hose shouldn’t be necessary but we are taking about the brake system. The unit should be rated for -dB attenuation. Pump inlets and outlets are like small horn speakers.

steve! it's not that loud, i guess i should be happy

the original mounting holes cause interference witt the compressor mount so i had to drill new holes

All these pumps have an exhaust where it blows out the air. It is unmuffled.

https://www.ebay.com/itm/145724084017

Put one of these on that exhaust. It will reduce a good deal of the noise. Just hook it up with some heater hose and screw clamps. Nothing that NASA needs to be consulted with on.

https://www.mcmaster.com/4869K72-4869K714/

Mounting the pump with rubber mounts will help minimize the transfer of mechanical vibration. Mounting it solid to a panel can actually amplify the vibration/sound.

The cheapest ones reduce the sound 13dB. The best ones 40dB. That is a very noticeable reduction.

I am not aware of any of the vacuum pumps being supplied with any kind of mufflers. So anything will help some.

Sound propagation and attenuation can be tricky. The effective attenuation of these mufflers is not the same across the sound spectrum. The sound/noise the pump is making from the inlet is not one frequency and the muffler specs don't offer the attenuation frequency curve. The range they publish is likely based on how they are used and at a specific frequency. Maybe they show it in their instructions. Anyway, depending on how loud the un-muffled pump inlet is (a typical vacuum cleaner is about 70 dB to 80 db) an attenuation of at least 20 dB will be very significant and quiet at -30 dB.

@Bell3156 posted:

it's pretty loud, a cheap one must be crazy . i'm mounting it to the passenger side splash had it has dynamat on it now

i have an original vaccum canister somehwere

I mounted mine behind the driver's side headlamp. There's quite a bit of room there. The pump I used was designed for electric cars but I've been unable to find a current supplier. I've heard the Hella vacuum pumps are compact and quiet. I believe Summit stocks them. 

Dan, do you have an update on how your new vacuum pump sounds and works.  Thank you.

Steve, aside from the fact the motor does not draw much vacuum, have you started it yet and tried it?  Always curious how much you really need to make it stop.  

Not long ago I test drove a Pantera with Weber carbs.  Weber manifolds (like the one I have) are individual runners to each intake port on the cylinder head. There is no shared plenum between the cylinders and thus no consistent source of vacuum  for power brakes, vacuum advance, etc.  Before test driving the car I saw it had what at first looked like nitrous lines plumbed to each intake runner.  Then I deduced that it was an attempt to provide vacuum to power brakes.  Before driving the car I could feel a very firm brake pedal.  Its brake hydraulics were working well.  Upon driving the car I found that power assist brakes were nonexistent even though it was plumbed for such.  It was not pleasant trying to stop this particular car.

My new GTS project came with a vacuum pump in leu of manifold vacuum for the brake booster.  They even reused the stock brake booster tube in the car's belly as plumbing for nitrous.  

I have no plans to try to use manifold vacuum for the brake booster on this car.  My hunch is that the new $400 vacuum pump from Leed Brakes will be money well spent in this case.  While the existing pump might get the job done its unpleasant sound and vibration will most likely be minimized compared to this new pump.

Here is a photo of the nitrous tank that is now retired.  It was plumbed through the booster vacuum tube to the car's 8 stack individual runner EFI.

steve,

im

pretty happy with it, i drove it for about 5 miles today and only heard it along with the fuel pump on start up

if you use button head bolts you may not have to drill new mounting holes above original homes, they might clear the compressor mount

Thanks Dan.