Originally Posted by mach4 (Post 3257562)

I thought I would start a thread on a project to replace the engine driven vacuum pump on a 617 engine with an electrical pump.

There are a number of donor options and in doing the research on possibilities I created a list of possibilities.

2005-09 Audi A8 Quattro [8E0 927 317]
2004-06 VW Touareg [8E0 927 317]
2001-05 VW Passat [8E0 927 317]
1998-01 Audi A4/A6 [8E0 927 317]
1999-05 VW Jetta [1J0612181B and D]
1999-13 Volvo (most) [31317445]
1999-03 Saab 9-5 95 [46 46 220]
1994-99 Saab 9-3 900 9000 93 [46 46 220]
2011-12 Chevy Cruz [13343961] * (Pump appears ok, the problem is with a switch)

In an initial trip to the junk yard I found a VW pump but it was way too expensive. Today I found one for under $20 so I grabbed it. It came off a Passat. Here is what they look like.

http://www.peachparts.com/shopforum/...1&d=1387523554

I haven't ordered the vacuum switch yet but will shortly.

Right now I'm working on a design for a bracket and will get the pump mounted up before proceeding with the switch and relay.

The reason for the conversion is to eliminate the possibility for the engine driven pump to spill it's bearings and take the engine out.

There are at least two ways to control the pump. The first is with a controller. This is one that is used to control vacuum in a CNC machine environment.

http://www.peachparts.com/shopforum/...controller.jpg

It's $95 and is available on the BuildYourOwnCNC web site.

The other option is to use a switch and relay. I'm leaning toward this switch, which is available from EVParts

http://www.evparts.com/products/stre...250&height=300
Pictures and progress to come.

Originally Posted by Jooseppi Luna (Post 3257663)

Cool! Methinks I'll be following your lead soon... the VP in my 'SD has 211k on it, so I need to replace it anyway.

Originally Posted by JB3 (Post 3257694)

where is this mounted in the VW application? does it have a special mount to cut down on noise?

Originally Posted by Dan Stokes (Post 3257671)

Thanks for this post. I've been kicking this idea around but you have a prettier solution than I've come up with. I'll only need it for shut off in the S-10 but I want it to be fool proof (given my level of "fool" that'll be tough).

What is that switch used on? Is it something I can scrounge at PnP? And is the VW pump Diesel-only or do lots of Vdubs have them?

Originally Posted by Smoker (Post 3257767)

For shutdown I'd guess the saab (and many other euro gasser) cruise control assist vacuum pump would be fine.

If someone wants I can yank one off a parts car and measure the vac.

Originally Posted by funola (Post 3257789)

Thanks for posting this. I'll be following your progress. Does the car you took the vac pump from have a vac reservoir and vac switch? Have you looked into whether removing the cam driven vac pump will cause any issues with what drives it (the timing device)?

Originally Posted by funola (Post 3257789)

Thanks for posting this. I'll be following your progress. Does the car you took the vac pump from have a vac reservoir and vac switch? Have you looked into whether removing the cam driven vac pump will cause any issues with what drives it (the timing device)?

Originally Posted by Jooseppi Luna (Post 3257793)

Some folks over at STD have eliminated the vac pump, I think. I'll see if I can find that...

Originally Posted by cho (Post 3257650)

.

another cool project I might consider...out of curiosity...why do we
need to control vacuum pump?


edit: is it just a on/off so it is not runnin' all the time...lot of folks converting to ecars use similar solutions fwiw..
also good switch and relay 24+18 bucks



thanks

cheers
ChO

.

Originally Posted by pawoSD (Post 3257691)

211k? The VP in my 300sd has 321k and works fine....I'm not worried. I had it off around 280k and it was in perfect shape inside. We have several 617's with original pumps and high miles with 0 issues.

I think there's a lot of VP paranoia around here, how many have actually had one fail? I replaced the one on my OM601 with a new engine mounted one because the original had 250k on it and was the exposed bearing variety. The new one has closed bearings and has been working great for 6k so far...

Originally Posted by mach4 (Post 3257758)

If you only need a shutoff solution, this is gross overkill. Use a vacuum pump from a Benz that is used for locking and unlocking. Dirt cheap readily available and low enough draw you shouldn't even need a relay.

There are no vacuum switches used on these pumps in their native installation. There is a vacuum sensor that is tied into the ECU that activates a relay when needed. Same exact operation as the electronic controller in post 1.

Originally Posted by funola (Post 3257789)

Thanks for posting this. I'll be following your progress. Does the car you took the vac pump from have a vac reservoir and vac switch? Have you looked into whether removing the cam driven vac pump will cause any issues with what drives it (the timing device)?

Originally Posted by Diesel911 (Post 3258000)

The other problem is that if you have a Mercedes Diesel with an Automatic Transmission there is always some Vacuum leaking out of the Transmission Vacuum Valve on the Fuel Injection Pump so it is possible your Vacuum Pump may never turn off or only be off for a short time.

Originally Posted by pgringo (Post 3258106)

I have the same vw vac pump I set up with a vac switch (22hg adjustable off eBay) and relay. With a Volvo 240 vac reservoir (fits perfect between firewalls next to master cylinder). It works great except I have a 300sd so the trans has a constant vac bleed. I was pizzed!

Originally Posted by pgringo (Post 3258136)

Because of the trans bleed, the vac pump only cycles off for a couple of seconds at a time. It'll probably burn up in no time.

Originally Posted by pgringo (Post 3258136)

Because of the trans bleed, the vac pump only cycles off for a couple of seconds at a time. It'll probably burn up in no time.

Originally Posted by 4x4_Welder (Post 3258274)

I thought that was already busted by testing and math?

Originally Posted by OM617YOTA (Post 3258002)

I have the EXACT same pump on my conversion. It handles all the vacuum requirements for the whole vehicle, and works just fine without heating up beyond design limits.

Originally Posted by Jooseppi Luna (Post 3258214)

How much does it run in normal operation?

Originally Posted by yvairguy (Post 3258305)

Going at it backwards need to know how Mercedes calculated the required vacuum then find a pump that can equal that.

Originally Posted by 4x4_Welder (Post 3258274)

I thought that was already busted by testing and math?
The Ford Superdutys use an electric vacuum pump, does it have a switch built in?

Originally Posted by mach4 (Post 3258289)

But you're running a manual transmission if I recall correctly.

It is starting to look like the transmission vacuum bleed is going to put it over the limit for what the VW/Audi vacuum pump can handle.

I'd considered the VCV when I was planning the conversion and my assumption was that the amount of bleed was quite small and wouldn't be an issue. Guess that's the problem with making certain assumptions. My reasoning was based on the relative sizes of the vacuum hose servicing the brakes vs the size of the vacuum hose servicing the rest of the vehicle.

It turns out to be true that exhaust port on the pump is actually smaller than the ID of the nylon vacuum lines

http://www.peachparts.com/shopforum/...1&d=1387609875

This whole project is beginning to look more and more unworkable. The good news is that I've only got $20 and a few hours into it to this point.

Originally Posted by funola (Post 3258360)

Have you tried adding a reservoir? If not, try it before giving up up. Make sure you have no leaks in the system.

Originally Posted by mach4 (Post 3257831)

I'm not touching anything on the side of the IP. All I'm going to do with the VP is remove the piston. Then the vacuum pump housing will become the functional equivalent of a block off plate. I'll weld the check valve to seal up the unit.

I'm not sure if there is a reservoir on the VW. There is no vacuum switch as the pump is controlled by the ECU as shown here.

http://www.peachparts.com/shopforum/...closedloop.jpg

For the technically inquisitive, here it an extensive write up - http://www.volkspage.net/technik/ssp/ssp/SSP_257.pdf I found the section on open-loop systems particularly interesting as there is no pressure sensor used in these designs, rather they use indirect measurements of load, rpm, throttle position and brake light switch to calculate whether the pump needs to be on. This can be done because in a gas engine, vacuum will be low at idle (if there is a big cam), and at lower rpms when the throttle plate is in the open position, and of course if the brake light is on there is demand for vacuum by the booster.

Originally Posted by pgringo (Post 3258301)

with the car idling and no brakes applied, it goes off & on about every second or half second. :mad:

edit: the vac switch i used had ebay heading of: Adjustable Universal Vacuum switch 6-22 inHG lockup 700r4 2004r 350c

Originally Posted by mach4 (Post 3258289)

But you're running a manual transmission if I recall correctly.

It is starting to look like the transmission vacuum bleed is going to put it over the limit for what the VW/Audi vacuum pump can handle.

I'd considered the VCV when I was planning the conversion and my assumption was that the amount of bleed was quite small and wouldn't be an issue. Guess that's the problem with making certain assumptions. My reasoning was based on the relative sizes of the vacuum hose servicing the brakes vs the size of the vacuum hose servicing the rest of the vehicle.

It turns out to be true that exhaust port on the pump is actually smaller than the ID of the nylon vacuum lines

http://www.peachparts.com/shopforum/...1&d=1387609875

This whole project is beginning to look more and more unworkable. The good news is that I've only got $20 and a few hours into it to this point.

Originally Posted by pgringo (Post 3258301)

with the car idling and no brakes applied, it goes off & on about every second or half second. :mad:

edit: the vac switch i used had ebay heading of: Adjustable Universal Vacuum switch 6-22 inHG lockup 700r4 2004r 350c

Originally Posted by OM617YOTA (Post 3258477)

Mine does that too sometimes. There is no range on my vacuum switch, it's just on or off at a set point. You may not have as much of a vacuum bleed as you're thinking.

Shortly in the works is an adjustable vacuum switch like Mach4 has.

Mach-

Indeed I do have a manual trans.

Originally Posted by OM617YOTA (Post 3258002)

I have the EXACT same pump on my conversion. It handles all the vacuum requirements for the whole vehicle, and works just fine without heating up beyond design limits.