# [EVDL] vacuum pump noise



## EVDL List (Jul 27, 2007)

What is the best way to reduce the noise from the vacuum pump? 
Despite it having rubber washers to separate it from the wheel well 
it is quite noisy. The controller also has some noise that is 
probably normal, but with all the "quite" it is rather annoying! 
Thanks, Dan

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## EVDL List (Jul 27, 2007)

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## EVDL List (Jul 27, 2007)

The noise in the vacuum pump is sometime cause by the check value in the 
vacuum pump that pops open and close which is more noisy at lower in.hg. As 
the vacuum builds up to above 15 in.hg. it should decrease in the noise 
factor and when you get to about 18 in.hg. then there is hardly any noise at 
all and at 22 in.hg., I can't here it.

If you do not have a large enough canister that should have addition vacuum 
check valves before and after the canister, plus addition check values for 
each addition vacuum take off, the bleed down will be faster and you may not 
get to the higher vacuum reading.

Of course if you have a vacuum pump that only goes to 15 in.hg., then you 
will always have some noise.

I install a vacuum meter on this system, which I find that the noise is 
greater at initial start up and it fades away when it gets above 18 in.hg.

I am using a GMC vacuum pump design for a diesel truck. It is a radial vane 
type that will pull 22 in.hg. For some devices that required a lower 
vacuum, than a GMC vacuum value can be added which adjusts the vacuum to any 
setting as needed.

Tubing will not work, because the through bolt still transmit the noise to 
the chassis. Use rubber insert nuts on the vacuum pump which is then 
mounted to a 1/4 inch thick aluminum plate, and then mount that aluminum 
plate with rubber insert nuts to your mounting area. You can get these 
rubber insert nuts from a hardware store.

Roland


----- Original Message ----- 
From: "Dan Whitley" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Sunday, August 19, 2007 2:08 PM
Subject: [EVDL] vacuum pump noise


> What is the best way to reduce the noise from the vacuum pump?
> Despite it having rubber washers to separate it from the wheel well
> it is quite noisy. The controller also has some noise that is
> probably normal, but with all the "quite" it is rather annoying!
> Thanks, Dan
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
> 

_______________________________________________
For subscription options, see
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## EVDL List (Jul 27, 2007)

Actually, Roland, your pump is different than the ones most of us use. We typically use diaphragm pumps. These are reliable and sturdy, and do not technically require a separate check valve (though it is a good idea to include one) because there is a very high resistance to leak through due to the design of the pump. The reliability (and the fact they already make one in the right size that runs off of 12VDC) is probably why nobody has yet tried to make something better specifically for EV's. Even the one Victor offers is a diaphragm style, I believe (correct me if that is wrong, Victor).

They make a lot of noise by the very design of the pump. It is unbalanced, as well as the fact it pumps that rubber diaphragm back and forth, and it also uses reed style valves that can add additional noise.

In contrast to yours, the diaphragm style pump radiates its noise from two sources - the secondary source is the vibration it transmits through the supporting structure. The primary source is from the diaphragm and is transmitted out the exhaust, which is why filtering the exhaust does a decent job of silencing it.

A vane style pump like yours, if functioning correctly, should make very little noise, but does require a separate check valve, as there is a large leak path even when the pump is new. It can draw down a vacuum very quickly, though.

If it does make noise (and is functioning properly), it is likely due to the cam (liner) design allowing the blades to experience shock. The only way to ensure this does not happen is to cut a cam profile (specifically a cycloidal profile) into the interior of the liner. Most pumps typically just use a circle, though, because it is easier to make. The noise is acceptable, because a diesel engine will easily drown it out, even just idling!

Personally, I'd be interested in the part number you are using, where to get them, and how quickly it draws down a vacuum. Are you running it off of your acessory drive system?





David Brandt


----- Original Message ----
From: Roland Wiench <[email protected]>
To: Electric Vehicle Discussion List <[email protected]>
Sent: Sunday, August 19, 2007 7:06:49 PM
Subject: Re: [EVDL] vacuum pump noise


The noise in the vacuum pump is sometime cause by the check value in the 
vacuum pump that pops open and close which is more noisy at lower in.hg. As 
the vacuum builds up to above 15 in.hg. it should decrease in the noise 
factor and when you get to about 18 in.hg. then there is hardly any noise at 
all and at 22 in.hg., I can't here it.

If you do not have a large enough canister that should have addition vacuum 
check valves before and after the canister, plus addition check values for 
each addition vacuum take off, the bleed down will be faster and you may not 
get to the higher vacuum reading.

Of course if you have a vacuum pump that only goes to 15 in.hg., then you 
will always have some noise.

I install a vacuum meter on this system, which I find that the noise is 
greater at initial start up and it fades away when it gets above 18 in.hg.

I am using a GMC vacuum pump design for a diesel truck. It is a radial vane 
type that will pull 22 in.hg. For some devices that required a lower 
vacuum, than a GMC vacuum value can be added which adjusts the vacuum to any 
setting as needed.

Tubing will not work, because the through bolt still transmit the noise to 
the chassis. Use rubber insert nuts on the vacuum pump which is then 
mounted to a 1/4 inch thick aluminum plate, and then mount that aluminum 
plate with rubber insert nuts to your mounting area. You can get these 
rubber insert nuts from a hardware store.

Roland


----- Original Message ----- 
From: "Dan Whitley" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Sunday, August 19, 2007 2:08 PM
Subject: [EVDL] vacuum pump noise


> What is the best way to reduce the noise from the vacuum pump?
> Despite it having rubber washers to separate it from the wheel well
> it is quite noisy. The controller also has some noise that is
> probably normal, but with all the "quite" it is rather annoying!
> Thanks, Dan
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
> 

_______________________________________________
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http://lists.sjsu.edu/mailman/listinfo/ev



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## EVDL List (Jul 27, 2007)

Frankly, the solution to the noise problem is to eliminate the vacuum 
booster and thus the pump. I just pulled it off my Fiero today, and the 
brake pedal assembly out of the car. It looks like I can get another 
50% pedal leverage.

Does anyone know what force multiplier a brake booster provides?
From the design it seems to be an on-off setup.
I've tried to find the info on the web, no such luck as yet.

Jack



> David Brandt wrote:
> > Actually, Roland, your pump is different than the ones most of us use. We typically use diaphragm pumps. These are reliable and sturdy, and do not technically require a separate check valve (though it is a good idea to include one) because there is a very high resistance to leak through due to the design of the pump. The reliability (and the fact they already make one in the right size that runs off of 12VDC) is probably why nobody has yet tried to make something better specifically for EV's. Even the one Victor offers is a diaphragm style, I believe (correct me if that is wrong, Victor).
> >
> > They make a lot of noise by the very design of the pump. It is unbalanced, as well as the fact it pumps that rubber diaphragm back and forth, and it also uses reed style valves that can add additional noise.
> ...


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## EVDL List (Jul 27, 2007)

Hello David,

I purchase the GMC vacuum pump for a GM dealer. Any one will do, a Chevy or 
GMC is the same. It is a belt driven type that is mounted to a GMC engine 
front mount accessory unit, that holds a Delco inverter-alternator, air 
conditional pump and a place for the vacuum pump and canister, and two 
electric drive motors that fit in the same spot that the power steering 
would be. The power steering unit is a separate mounted electric unit.

If you are running a automatic transmission like I am, make sure you get the 
GMC vacuum value that attaches to the accelerator linkage, that controls the 
transmission pump pressure like a engine vacuum would.

The pilot shaft of the main motor can also drive these units using a 
electric clutch that is engage when the accelerator unit is off, or the 
electric motor comes on line when the accelerator is on.

One of the large Buick's has a nice aluminum accessory frame work that also 
attaches to the front of the engine which will work by attaching it to the 
front of the new Warp 11 motors that has six tap bolt holes on the front 
motor face.

Roland






----- Original Message ----- 
From: "David Brandt" <[email protected]>
To: "Electric Vehicle Discussion List" <[email protected]>
Sent: Sunday, August 19, 2007 6:41 PM
Subject: Re: [EVDL] vacuum pump noise


> Actually, Roland, your pump is different than the ones most of us use. We 
> typically use diaphragm pumps. These are reliable and sturdy, and do not 
> technically require a separate check valve (though it is a good idea to 
> include one) because there is a very high resistance to leak through due 
> to the design of the pump. The reliability (and the fact they already 
> make one in the right size that runs off of 12VDC) is probably why nobody 
> has yet tried to make something better specifically for EV's. Even the 
> one Victor offers is a diaphragm style, I believe (correct me if that is 
> wrong, Victor).
>
> They make a lot of noise by the very design of the pump. It is 
> unbalanced, as well as the fact it pumps that rubber diaphragm back and 
> forth, and it also uses reed style valves that can add additional noise.
>
> In contrast to yours, the diaphragm style pump radiates its noise from two 
> sources - the secondary source is the vibration it transmits through the 
> supporting structure. The primary source is from the diaphragm and is 
> transmitted out the exhaust, which is why filtering the exhaust does a 
> decent job of silencing it.
>
> A vane style pump like yours, if functioning correctly, should make very 
> little noise, but does require a separate check valve, as there is a large 
> leak path even when the pump is new. It can draw down a vacuum very 
> quickly, though.
>
> If it does make noise (and is functioning properly), it is likely due to 
> the cam (liner) design allowing the blades to experience shock. The only 
> way to ensure this does not happen is to cut a cam profile (specifically a 
> cycloidal profile) into the interior of the liner. Most pumps typically 
> just use a circle, though, because it is easier to make. The noise is 
> acceptable, because a diesel engine will easily drown it out, even just 
> idling!
>
> Personally, I'd be interested in the part number you are using, where to 
> get them, and how quickly it draws down a vacuum. Are you running it off 
> of your acessory drive system?
>
>
>
>
>
> David Brandt
>
>
> ----- Original Message ----
> From: Roland Wiench <[email protected]>
> To: Electric Vehicle Discussion List <[email protected]>
> Sent: Sunday, August 19, 2007 7:06:49 PM
> Subject: Re: [EVDL] vacuum pump noise
>
>
> The noise in the vacuum pump is sometime cause by the check value in the
> vacuum pump that pops open and close which is more noisy at lower in.hg. 
> As
> the vacuum builds up to above 15 in.hg. it should decrease in the noise
> factor and when you get to about 18 in.hg. then there is hardly any noise 
> at
> all and at 22 in.hg., I can't here it.
>
> If you do not have a large enough canister that should have addition 
> vacuum
> check valves before and after the canister, plus addition check values for
> each addition vacuum take off, the bleed down will be faster and you may 
> not
> get to the higher vacuum reading.
>
> Of course if you have a vacuum pump that only goes to 15 in.hg., then you
> will always have some noise.
>
> I install a vacuum meter on this system, which I find that the noise is
> greater at initial start up and it fades away when it gets above 18 in.hg.
>
> I am using a GMC vacuum pump design for a diesel truck. It is a radial 
> vane
> type that will pull 22 in.hg. For some devices that required a lower
> vacuum, than a GMC vacuum value can be added which adjusts the vacuum to 
> any
> setting as needed.
>
> Tubing will not work, because the through bolt still transmit the noise to
> the chassis. Use rubber insert nuts on the vacuum pump which is then
> mounted to a 1/4 inch thick aluminum plate, and then mount that aluminum
> plate with rubber insert nuts to your mounting area. You can get these
> rubber insert nuts from a hardware store.
>
> Roland
>
>
> ----- Original Message ----- 
> From: "Dan Whitley" <[email protected]>
> To: "Electric Vehicle Discussion List" <[email protected]>
> Sent: Sunday, August 19, 2007 2:08 PM
> Subject: [EVDL] vacuum pump noise
>
>
> > What is the best way to reduce the noise from the vacuum pump?
> > Despite it having rubber washers to separate it from the wheel well
> > it is quite noisy. The controller also has some noise that is
> > probably normal, but with all the "quite" it is rather annoying!
> > Thanks, Dan
> >
> > _______________________________________________
> > For subscription options, see
> > http://lists.sjsu.edu/mailman/listinfo/ev
> >
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
>
>
>
> ____________________________________________________________________________________
> Be a better Globetrotter. Get better travel answers from someone who 
> knows. Yahoo! Answers - Check it out.
> http://answers.yahoo.com/dir/?link=list&sid=396545469
>
> _______________________________________________
> For subscription options, see
> http://lists.sjsu.edu/mailman/listinfo/ev
> 

_______________________________________________
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## EVDL List (Jul 27, 2007)

I ran an experiment that I have mentioned before and you may like.

I removed the vacuum line and made an adapter around the shaft on the
pedal side where the air goes in
(in case the operation hasn't been explained..
vacuum doesn't pull on the booster, the atmospher is allowed to push
on it.
two sides have vacuum on it until you press on the pedal.
the pedal going forward shuts the valve between the two half's and
opens the valve in back
the weight of the atmosphere spills in pushing on the diaphragm
until it catches up with your
foot. At which time the valves switch again.)

On this adapter I put a regulator from a tank set to 15psi.

I was considering putting onboard air. something for the tires and the
brakes.
Thinking that a compressor is easier to quiet and would only have to
come on 1/10 of the time.
Plus air compressors are cheap and plentyful. A 150 psi tank that is a
liter or two may only need to be fllled once a week.
This is the second part of the experiment that I never got to.


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## EVDL List (Jul 27, 2007)

Jerry,

what do you mean by a 3 ft hose on the output side of the pump?

the side of the pump that outputs flow to the atmosphere?

I have the Gast vacuum pump. I vaguely recall a filter being on that side
of the pump?

If my vague memory isn't failing, would you recomend putting that filter
back on the end of the 3 ft. of hose?

that's 3/8 or 1/2" hose right? I'll double check, but just making sure
we're talking about the same thing.

Thanks, Ben

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## EVDL List (Jul 27, 2007)

[No message]


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## EVDL List (Jul 27, 2007)

Jerry,

what do you mean by a 3 ft hose on the output side of the pump?

the side of the pump that outputs flow to the atmosphere?

I have the Gast vacuum pump. I vaguely recall a filter being on that side
of the pump?

If my vague memory isn't failing, would you recomend putting that filter
back on the end of the 3 ft. of hose?

that's 3/8 or 1/2" hose right? I'll double check, but just making sure
we're talking about the same thing.

Thanks, Ben


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## EVDL List (Jul 27, 2007)

*[EVDL] Vacuum pump noise*

What pump are you using? I have the MES-DEA units from Metric Mind. 
They're the loudest things on both my EVs. Not too noticeable in the car, 
but the only mounting spot in the truck was over the front fender well. 
VERY loud on the inside, even with the rubber mounting feet, extra 
padding, etc.

I finally wrapped the pump in foam rubber and used a large zip-tie to 
attach it to the junction box that holds my contactors & circuit breaker. 
Not pretty, but now it's a quiet hum that's barely audible from the inside 
- making the Dayton blower fan the biggest noise maker.

Adding a plastic straw to the pump exhaust does make it a bit quieter, but 
not much. Mostly it's the transmitted vibration that I hear. The straw 
helps more when I first turn the car on in the morning. The pump gets 
quieter as the vacuum increases, so after the initial pump down it's not 
as loud when it cycles back on - there's already a partial vacuum in the 
reservoir.

-Adrian



> John G. Lussmyer wrote:
> > I realized tonight that the power steering pump is NOT that noisy.
> > It's the vacuum pump causing most of the noise. I have to see about
> > adding a muffler to it. It's already on rubber mounts.
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Vacuum pump noise*

This is the problem with a diaphragm type of vacuum pump. You get the plop 
plop noise no matter how fast you drive the EV. The pump is cycling from a 
low in.hg setting to a high in.hg setting with a vacuum switch that controls 
the pump drive.

Also when the vacuum pump just starting up and the in.hg is low, the check 
value in the pump is slamming back and forth which makes a pop pop noise. 
Now you get a plop pop plop pop combination noise.

If you take the motor it self and run it not driving the pump, some of these 
motor at full rpm have whine whine noise. When the motor is running the 
vacuum pump, you get a whine plop pop noise now.

I use a vane type vacuum pump which is driven off the pilot shaft of the 
main motor and/or a PM motor. The pump also has a check value that clang 
clang when first starts and reduces in sound level until there is no sound 
at 15 in.hg.

My working in.hg. while I drive the vehicle is from 15 in.hg. to 22 in.hg. 
At first I try to drive this pump with out a canister to see what's happen. 
I can get the vacuum up to 22 in.hg. using no vacuum assist devices. If I 
brake 4 times while the motor is stop, the in.hg. will come down to 8 in.hg. 
and I would get that plop pop noise again.

So, I bought a vacuum canister from jegs.com that also has a vacuum check 
valve plug into the canister. It's the same type of check valve use in the 
brake vacuum booster. This check valve keeps the vacuum in the tank 
bleeding back through the a vacuum pump and holds more of a constant vacuum.

With the canister, I can pump four times with the motor off, and the vacuum 
only drops to 12 in.hg. I now go read the directions on installing a vacuum 
pump and canister. It's is recommended that any tap off the main vacuum 
line between the canister and brake booster that is use with other vacuum 
assist devices which I four for the heating and A/C, is to install a vacuum 
check valve on the tap off line and install another vacuum canister with its 
built in check value that goes to the vacuum assist motors.

After I made this change, I now can pump the brake four times and the in.hg 
comes down to 15 in.hg and there is no more pop plop at that level of in.hg.

The loudest thing on my EV is if I have the window crack open a bit, is I 
can hear the tires crunching the rough road surface.

Roland




> John G. Lussmyer wrote:
> 
> I realized tonight that the power steering pump is NOT that noisy.
> It's the vacuum pump causing most of the noise. I have to see about
> ...


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## EVDL List (Jul 27, 2007)

*Re: [EVDL] Vacuum pump noise*

I don't see this as a problem. My EV is dead quiet (npi) & when I slow for a j walking pedestrian I get a quick surprised head turn. I see noise as a benefit of any ev component except the motor. Lawrence Rhodes...Wishing for squeaking brakes.

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