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
> >
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