DIY Electric Car Forums banner

1 - 11 of 11 Posts

·
Registered
Joined
·
202 Posts
Discussion Starter #1
I just built a vacuum reservoir out of PVC that is about 4"x20". When I was mounting it I noticed that I have enough room to make it 2-3 times that long and still fit it under the car. That left me wondering Is there any disadvantage to making it as big as possible? Should I use a check valve between the pump and reservoir and one at the booster?

Thanks for any info.
I think I'm going to like being able to stop.
 

·
Admin: 'one of many'
Joined
·
4,838 Posts
The size of the reserviour is going to affect how often the pump runs and how long it takes to get full vacuum.
It will depend on the size of the pump. If you have a high capacity pump then you can have a bigger reserviour.

A big reserviour will just take longer to reach full vacuum then a smaller one wth the same pump. However, a larger reserviour will mean the pump may operate less frequently but for longer each time.
 

·
Registered
Joined
·
440 Posts
Aloha, when I got my Yaris that was already EV converted, it had NO reservoir and I was disappointed in the brakes. I though a res. was needed and now you guys confirm it.
Right now, when you hit the brakes, you hear the pump come on and it seems are not very effective for 2 seconds then becomes easier to push and stop better.

My pump is a MES-DEA 70/6E and seems to have a small relay turning it on and off from action from the brake petal.

thanks francis
 

·
Registered
Joined
·
202 Posts
Discussion Starter #5 (Edited)
The res that I put on mine was a big help but my pump is weak. It only pulls about 15"Hg after 5 minutes. I think most boosters need about 18+"hg. I am trying 3 of those surplus center pumps next. At $15 dollars a piece they were worth trying out.

Link to the pumps:
https://www.surpluscenter.com/item.asp?item=4-1801&catname=air

I think a pressure switch and reservoir are the best way to go. Without a res of some kind the pump would have to move some serious volume to keep up.

I hope the surplus center pumps work because I over engineered the mount that I made for them.


 

·
Registered
Joined
·
71 Posts
The res that I put on mine was a big help but my pump is weak. It only pulls about 15"Hg after 5 minutes. I think most boosters need about 18+"hg. I am trying 3 of those surplus center pumps next. At $15 dollars a piece they were worth trying out.

Link to the pumps:
https://www.surpluscenter.com/item.asp?item=4-1801&catname=air

I think a pressure switch and reservoir are the best way to go. Without a res of some kind the pump would have to move some serious volume to keep up.

I hope the surplus center pumps work because I over engineered the mount that I made for them.
I ordered a surplus center pump also. How are they working out for you? Nice mount. Mine isn't going to be quite that nice.
 

·
Registered
Joined
·
2,494 Posts
Maybe you should try just one first... .?? It says it will do 25" hg.... That should be more than enough.
The price sure is right! lol
 

·
Registered
Joined
·
440 Posts
I already have the MES-DEA 70/6E that came with the car when I bought it. Just wondering if a reservoir would help as it seems the pump needs 1-2 seconds to activate the brake booster and to me is a bit freaky. I see the MES has a pressure regulator built in so it seems the easiest way is to run to Home Depot and fit a 2" x 28" PVC pipe, thread a "tee" in and see if there is any improvement in brake activation.

francis
 

·
Registered
Joined
·
604 Posts
Hi; No-one has mentioned this as yet but PVC will be prone to collapse if it is near a heat source. I discovered this when trying Hydrogen; I let the electrolyte run low and the geny pulled excess amps , generated heat that started a fire in the container, but the container had collapsed under vacuum before this. I know you wont be near a lot of heat, but small trucks have a nice vacuum tank, eg Toyota Dyna.
 

·
Registered
Joined
·
202 Posts
Discussion Starter #11
The surplus center pumps work great so far. When I "start" the car it takes 5 seconds to pump down the reservoir. Once its at about 22 inHg they shut off. It takes 2 full presses before they need to come back on which is at about 18 inHg. If I stomp the pedal repeatedly the vac wont go below 15 inHg. Might not even need the res. There is always a good pedal now.

I'm using 3/8 ID hard plastic line from the hardware store. The white translucent stuff. The pumps run off of the 144v pack through a standard 12v relay triggered by a vac switch.

The pumps are way easier to hook up if you remove the 4 screws in the top and rotate the inlets 180 degrees so they don't point right at the motor body. There is a little locating notch that needs to be cut/filed off to rotate them

They are a little bit loud but I don't hear them over wind/road noise. Only when stopped.
 
1 - 11 of 11 Posts
Top