# Vacuum Pump Noise Levels



## Nick Smith (Oct 26, 2007)

Joey said:


> The newer VBS-VPDP-EV-12 is supposed to be <50 dB on their spec sheet. http://evolveelectrics.com/Braking Components.html


I am very interested to see if anyone has experience with this new vacuum pump. It is oil-less which according to Yutai sales rep means that it is cheaper to freight as it is not "hazardous' as far as FedEx are concerned. I wanted to buy the previous model as that is what I have experience of, but they ignore my requests and keep directing me to the new model.


----------



## rwaudio (May 22, 2008)

Joey said:


> I have the VBS-EV-12 vacuum pump kit for my EV. http://www.yutai.tw/English/vbs-ev.html
> 
> It works great, but the noise is great enough that I'm considering getting something else. I don't hear the pump above 20 MPH, but while parked or at low speed, it is spoiling the EV mood.
> 
> ...


I'm using the MES-DEA 70/6E and it's not that loud, however it does vibrate, so even if the noise doesn't get you the vibration can. I had previously relied on the built in rubber mounts to isolate it from the car and that worked ok, however like you say while stopped or at low speed it was starting to bother me.

I decided to reuse the old motor mount as an extra level of vibration resistance and milled a new mount for it. I've only sat in the car in the garage and let it run but the difference is very significant. More than anything I would say your mounting will determine the vibration as well as to a certain extent the noise.


----------



## TTmartin (Feb 7, 2012)

Joey said:


> I have the VBS-EV-12 vacuum pump kit for my EV. http://www.yutai.tw/English/vbs-ev.html
> 
> It works great, but the noise is great enough that I'm considering getting something else. I don't hear the pump above 20 MPH, but while parked or at low speed, it is spoiling the EV mood.
> 
> ...


I and quite a few others use the Audi Vacuum pump http://www.volkspage.net/technik/ssp/ssp/SSP_257.pdf
I've not used a decibel meter on mine, but it's not loud by any standard.
You can pick them up second hand at car Breakers.


----------



## ElectriCar (Jun 15, 2008)

I don't use mine for brakes but for the ventilation system. It is from a late model Ford diesel truck. It's very quiet with rubber isolation mounts. Installed inside a plastic box with insulation and you probably couldn't hear it. Has a pressure switch built in.

Link for pump


----------



## rwaudio (May 22, 2008)

rwaudio said:


> I'm using the MES-DEA 70/6E and it's not that loud, however it does vibrate, so even if the noise doesn't get you the vibration can. I had previously relied on the built in rubber mounts to isolate it from the car and that worked ok, however like you say while stopped or at low speed it was starting to bother me.
> 
> I decided to reuse the old motor mount as an extra level of vibration resistance and milled a new mount for it. I've only sat in the car in the garage and let it run but the difference is very significant. More than anything I would say your mounting will determine the vibration as well as to a certain extent the noise.


After driving the car for awhile with the new bracket I have to say that the same pump in almost the same location with another layer of isolation made a significant difference in noise and vibration. 

I bet you can make your existing pump quieter by changing it's mounting location/method or like ElectriCar mentioned putting it in a "box" of some sort.

DO NOT use the pump that ElectriCar linked to for brakes though, that style of pump simply can not keep up with the demand of power brakes, they are for vacuum operated vents and things only.


----------



## Joey (Oct 12, 2007)

TTmartin said:


> I and quite a few others use the Audi Vacuum pump http://www.volkspage.net/technik/ssp/ssp/SSP_257.pdf
> I've not used a decibel meter on mine, but it's not loud by any standard.
> You can pick them up second hand at car Breakers.


Nice document explaining the principle of operation. I can't find the tech specs like pumping speed or noise, but since it is OEM for brake servo, I've no doubt it would work.



rwaudio said:


> After driving the car for awhile with the new bracket I have to say that the same pump in almost the same location with another layer of isolation made a significant difference in noise and vibration.
> 
> I bet you can make your existing pump quieter by changing it's mounting location/method or like ElectriCar mentioned putting it in a "box" of some sort.
> 
> DO NOT use the pump that ElectriCar linked to for brakes though, that style of pump simply can not keep up with the demand of power brakes, they are for vacuum operated vents and things only.


I will try to double isolate the pump (rubber mount from the car to an intermediate bracket, and more rubber between the bracket and the pump). This is a common way to improve vibration transfer. 

Right now the pump is not mounted, just temporarily wedged into position with 2 inches of open cell foam all around.

Mounting the pump in a box of some sort is a little harder, but I'll see what I can do. I also have some visco-elastomer adhesive tape, to make the box double walled. This constrained layer damping system is done to kill any box resonances and improve acoustic isolation.  http://www.earsc.com/pdfs/engineering/understandingdamping.pdf

Of course, starting with a smaller noise source is the most effective approach, but I'll try with the pump I have, first.

It looks like most of the pumps used for brake vacuum have an ultimate pump down pressure of at least 21 inHg (0.7 bar below atmosphere). My pump has a no load pumping speed of 60 liter/sec and it pumps down a 2.5 liter volume in about 2 seconds. The pump comes on every 2 or 3 brake cycles. I want to stay above 20 l/s, and 30 l/s would give a lot of margin. I like to see a datasheet like this before purchasing a component: http://www.cebi.de/easyCMS/FileManager/Files/MES/Vacuum_pumps


----------

