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Old 03-03-2010, 08:28 AM   #1 (permalink)
PaleMelanesian's Disciple
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Electric Vacuum pump

Hi Folks, I am back, after some hibernation!

I have put on (finally) the MPGuino I got a loong time ago, and put in a kill switch. Other than that I pretty much have my car stock, with 50 PSI air, and not much else to talk about.

I have been a disciple of PaleMelanesian, and relish my EOC very much. In the past 15 months or so that I have been practising it, I have had fair amount of success using it.

Today I realized I am courting with disaster, because I had a particularly long stretch of engine off coasting, and there was a fair amount of traffic, though smooth flowing. I had pulsed up (something else playing on my mind) to about 80 kmph, and I had about 500m to reach my office gates, with a roundabout to cross in between.

The pulse pushed me near the vehicles in front, and as I tend to conserve momentum, I managed to keep the car between the kerb and the other vehicle. I had to apply brakes lightly (it is avoided as much as possible) and then I turned into the approach to my office main gate, where I need to stop for a security check.

To my horror, I found that my brakes won't apply as easily. I am usually aware of the vacuum depleting with use of brakes, and I generally bump up to replenish. In this case the momentum didn't prompt for a bump, and I was distracted because of the traffic - the use of brakes in between did not register. I had to brake real hard to get the car to stop at the security check.

I know, some of you are shaking heads, some are saying what a tool, does not remember to replenish vacuum, but it is the first time in about 15 months now that I agree that there can be lapses in concentration and awareness, which could lead to your not using brakes with necessary force in event of depleted vacuum.

There is a simple solution for it, at least theoretically - use a vacuum bottle + vacuum pump that operates electrically and use it for all the brake assist needs. I get the idea from Ben Nelson's conversion, where he used that white vacuum bottle with a pump with a cutoff when vacuum builds up.

I think this kind of vacuum replenishment accessory is very important for an EOC devotee, and it is as important as or more important than kill switch or an MPGuino. I think there would be some benefit in using the electric pump as well (mechanical stuff is generally less efficient - like say a belt driven fan vs. electric one)

Is this thing available from regular auto accessories shops? What are the alternatives? How do I go about and acquire or DIY one for myself? Please answer. I am so shaken from the morning incident, that I would get it done as soon as possible if it is feasible.

Last, but not the least, kick my butt and give me a link if something on this lines is already available. I tried to search, but in vain.

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Old 03-03-2010, 08:33 AM   #2 (permalink)
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If you simply add a vacuum tank to the car you could easily double the amount of 'vacuum' you have available. The pump IMO is overkill. Some members here have simply taken a PVC pipe, put caps on both ends, and then drill/screw a barbed fitting into one of the caps and connected it to the brake booster (or any place behind the check valve).
Current project: A better alternator delete
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Old 03-03-2010, 09:06 AM   #3 (permalink)
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Welcome back Hummingbird
So did you really sleep through winter? If only I could...

Daox is right about the additional vacuum tank. A vacuum pump is unnecessary since gas engines produce vacuum anyway. Diesels, on the other hand, need a pump, so they would benefit from switching to electric (on my to-do list). This would not only be much more efficient (as you noticed), but would also allow the pump to kick in when EOCing.
Ben used an electric pump because that's the only way to produce vacuum in an electric car.

Also, inspect your vacuum lines to make sure they don't leak.

Here are 2 links to DIY vaccum tanks:
Homemade PVC Vacuum Reservoir
Auxillary vacuum reservoir

BTW: Just a thought, but would it be possible to create vacuum while braking? Something like a mechanical pump in the wheels, replenishing your vacuum while you use it!
e·co·mod·ding: the art of turning vehicles into what they should be

What matters is where you're going, not how fast.

"... we humans tend to screw up everything that's good enough as it is...or everything that we're attracted to, we love to go and defile it." - Chris Cornell

Piwoslaw's Peugeot 307sw modding thread

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Old 03-03-2010, 05:58 PM   #4 (permalink)
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How about this. Instead of braking, hold down your kill switch as you put it in 4th or 5th and let out the clutch. EOEB - Engine-Off-Engine-Braking. You still haven't bumped your engine on, you haven't wasted a drop of fuel, and yet your vacuum is "full" (empty?) for some real braking.

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assist, brake, electric, pump, vacuum

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