# What is the quietest way to make a vacuum?



## billpong (Nov 10, 2009)

So I took the Gast Vacuum pump that I received with my EV kit, and mounted it on the wheel well and the switch on the side wall, and wired them up and hooked up all the hoses, and gave it a test. It seriously never occurred to me that it would make any sound at all! Oh my goodness was I surprised when I turned the ignition key! Are you kidding me? And its not just the decibel level alone, the actual sound it makes is extremely irritating by itself. Jeez!! 

Help!! New problem to solve. Who is creating a vacuum for their power brakes without making noise? Do they make noiseless vacuum pumps (using some different technology)? Can I hook something up to the front rotor that will create a vacuum? Who has solved this problem? (Note: I'm not interested in building a sound-proof chamber for a noisy vacuum pump). How do you create a vacuum without making noise?

thanks!!!
bill


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## TheSGC (Nov 15, 2007)

I mounted my Thomas pump on rubber mounts and that helped a lot, but it's still sounds like an aircraft carrier. I got use to it, and it lets me know that my brakes are working. 

One thing that I might try it to make a rubberized muffler for the intake port. Most of the noise appears to be air flow, so a large rubber muffler might quiet it down.


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## KiwiEV (Jul 26, 2007)

Ahh, the old vacuum noise problem... Noisy little suckers aren't they? (Pun intended). 

Rubber mounting's the way to go. I put mine on a rubber mat, _inside_ a wooden box. It still made a noticeable noise, but it was nowhere near as bad as it started out.

One method of cutting down noisy pumps I've seen, is to have the thing suspended off the body of the car. I saw one conversion where the pump was resting in a little hammock underneath the rear of the car. 
The guy was very happy with the result - apparently it produced a very quiet hum which was only heard when stopped on a calm day.


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## billpong (Nov 10, 2009)

Thanks for the info guys.. but I'm really asking about how to make a vacuum without noise in the first place... not how to suppress the noise after the fact.
For instance, I've seen references to a pump made in switzerland that claims to have low acoustic levels.
http://www.metricmind.com/pump.htm
Is anyone using this pump and can report on its noise level?
Are there any other pumps out there with low noise levels?

- bill


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## etischer (Jun 16, 2008)

I have the thomas pump. Putting a muffler on the exhaust port made a huge difference. I basically stuffed the exhaust port full of dense felt. It doesn't seem to affect how fast it sucks, but sure made it quieter. 

I also bought some rubber isolation mounts from mcmaster carr. I attached the whole thing to my motor mount which is also isolated with rubber mounts. I haven't had the need to go further with sound proofing, I can barely hear the pump while parked in the garage. On the road, I don't hear the pump at all.


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## Woodsmith (Jun 5, 2008)

I originally tried a Saab vacuum pump. It sounded like this:


I am planning on using the original air con compressor driven from the motor tailshaft (if it has one).

I did a video of it being bench tested.


And again with reservoir.


As you can hear, the AC compressor is quite quiet with most of the noise coming from the drive motor.


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## piotrsko (Dec 9, 2007)

probably the only way you will ever get true quiet is to use a positive displacement gerotor drive, but they are rare and pricey.

the other way is to totally isolate it from the mounting assy, with a remote intake somewhere in the say, trunk.

I like the hammock Idea....


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## Amberwolf (May 29, 2009)

For an isolated mount, you could also look at some of the DIY microphone iso mounts. Essentially a bunch of rubber bands or similar, bound in a web to hold the device suspended in air.
________
Pattaya realty


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## Dave Koller (Nov 15, 2008)

Always wondered if one took a large diaphragm and put a solenoid in the center and hooked it to the brake light switch - would it pull enough vacuum to do anything ?... sort of instant one big volume of SUCK .. How fast does it deplete? ( I know - might belong in the perpetual motion sticky LOL )

_I created a vacuum with __a Venturi (blew air across it to form vacuum for de-solder head..) 

Wondered if a shop vac would even work with muffler -- better - cheaper...



_


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## Guest (Mar 4, 2010)

Get a better vacuum pump. My pump on my TDI is quiet. Not removable to use elsewhere but quiet. Might find something like that which is an aftermarket pump. 

Pete


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## Guest (Mar 4, 2010)

Diaphragm pumps are very quiet and durable. This type of pump is oil-less and usually has a small footprint. They are ideal pumps for a vacuum system. Typical CFM rating is 1 to 3.

Pete


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## Jimdear2 (Oct 12, 2008)

piotrsko said:


> probably the only way you will ever get true quiet is to use a positive displacement gerotor drive, but they are rare and pricey.
> 
> the other way is to totally isolate it from the mounting assy, with a remote intake somewhere in the say, trunk.
> 
> I like the hammock Idea....


 
These pumps are usually very quiet, just a wirr and gurgle. The downsides are, size, cost, the need for it to be mounted near level and the need to maintain the oil level in the pump.

http://www.harborfreight.com/cpi/ctaf/displayitem.taf?Itemnumber=98076

There are also several higher capacity pumps of this type in Harbor Freight. But more costs more.


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## billpong (Nov 10, 2009)

OK.. So after talking to someone that has one, I ordered the 70/6E MES-DEA vacuum pump from
http://www.metricmind.com/
Apparently its not "silent" but it is a lot quieter than the gast noise machine that I have. I will post again next week to report if I'm happy with it. I'm keeping my expectations low.


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## esoneson (Sep 1, 2008)

Did you ever get your vacuum pump? For that amount of money it better be able to suck a golf ball through a garden hose with just a hummmmmmm.


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## dtbaker (Jan 5, 2008)

billpong said:


> ... mounted it on the wheel well


that is your problem. if you suspend from straps, or bolt thru a rubber pad, or do anything other than bolt to a drumhead (like the firewall or wheelwell), its really not that bad.


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## billpong (Nov 10, 2009)

Yes, I received the MES-DEA vacuum pump. I'm much happier with it. Compared to the gast pump it is:
1) cheaper (but not by much).
2) One self contained smaller widget with simple connections
3) much quieter (but still makes significant noise)
4) has rubber feet for mounts
5) has a single nice water-proof connector for electrical hook-up

So its quieter and much smaller with very simple hook-ups... I'm hoping it continues to work for a few years..


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## billpong (Nov 10, 2009)

Eventually I mounted it to a piece of polyethylene with a layer of neoprene and then another layer of neoprene with another piece of polyethylene.. etc.. before using a single bolt to attach it to the wheel well.. That helped some, but the gast pump is still very loud even if you lay it on the ground.
Some of it is the quality of hearing.. My old friends (60+) are not so much annoyed by it, but my younger friends think it is very annoying (your hearing goes as you get older). Same with my controller which whines at low speeds.. I hate that thing! but my old friends can't hear that frequency very well so they don't even notice it..
Personally, I'm annoyed by the 12 volt fan on the bottom of the controller.


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