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Brake Vacuum Pump Drag/Daily Setup

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Boomdeeze

10+ Year Contributor
2,140
373
Jul 5, 2009
Independence, Minnesota
I have read through the vacuum pump threads and none really go into detail on setup or how efficient they are. I was hoping to make a thread where anyone interested in setting up a vacuum pump could post here with questions or setups they have made.

I am looking to make a setup where the pump is only activated when I am approaching the staging light. I just bought the Audi brake vacuum pump off Ebay for $35 shipped. I have an automatic with low vacuum (-13inHg) so I need some time to spool and hold it at the line as I approach. I will need to inch forward so having max braking power is important. I have drawn up a diagram of how I am going to install my pump and wanted to make sure that what I am thinking will work. Here is the diagram:

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When the pump is not activated, the setup should work just as it would as OEM. The vacuum is supplied by the intake manifold and the vacuum pump valve should close. The trouble starts when I need to brake when I am stalling at the line and needing to inch forward into the lights. I would activate the vacuum pump which would close the OEM check valve(vacuum pump has higher vacuum) and open the second valve allowing the vacuum pump to supply the brake booster with more vacuum. So in theory, the only time the vacuum pump check calve would open would be when the pump is activated. Am I thinking this correctly in my head or is it too early in the day to plan this?
 
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It looks like it should work to me. I was going to do the same-type of thing with my car...or eliminate the intake manifold from the equation all together and just run it on the vacuum pump all the time (because its a race-only car) and deal with the insane pedal-feel.
 
It looks like it should work to me. I was going to do the same-type of thing with my car...or eliminate the intake manifold from the equation all together and just run it on the vacuum pump all the time (because its a race-only car) and deal with the insane pedal-feel.

I thought about that setup too but then the pump would be forced to run constant. I do drive my car on the street so the pump would be running all the time which I read they are not designed to do. The Audi pump is more of a vacuum assist so it shuts off when the vacuum reaches a certain point.

Did you end up do any vacuum pump setup?
 
I've got a couple of the VW/Audi pumps. There would have to be something controlling the pump in the OEM setting, then...since the pumps only are two-wire (power/ground). You could use a Hobbs switch to turn the pump on under boost if you wanted to...
 
With the diagram above, the pump could just be hooked up to a switch a turn on when I want the 20+ inHg of vacuum correct?
 
Use the EGR or FPS solenoid tab of link to control it through a relay. It can be on above XX throttle position, off above XX speed, etc etc. You could dial the parameters in to match your stall pretty perfectly.
 
Use the EGR or FPS solenoid tab of link to control it through a relay. It can be on above XX throttle position, off above XX speed, etc etc. You could dial the parameters in to match your stall pretty perfectly.

This sounds intriguing, have anymore details on this by chance? I would be nice to have it turn on in the 0-5 mph and 1500-4500 rpm range, that would be a very nice way to hook up the pump!
 
Set the RPM for 1500, max of 4500. Load would be say just under vacuum and into positive. Obviously speed under 4-5mph and TPS in the 75%+ range or whatever you log for TPS on your stall. Wire the relay into the EGR connector, and then the relay powers the vacuum pump.
 

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That would be a great way to set up that pump. I really only need the pump for the tree so I feel a switch would better fit my current needs. I think I will install the pump like the diagram and just wire the pump through the switch to turn on as I approach the line.

Has anyone installed a brake vacuum pump on this forum?
 
Looked at them....was waiting on you to tell me how good it works. :D I need better braking also, with -8hg of vacuum, sometimes the pedal is very hard.
 
I sure understand the low vacuum, iffy brakes when you really need them. I will be following, good luck. It looks like your diagram is correct in function, where the heck do you think you are going to mount it at?
 
Great question, this pump is not exactly compact haha I will take some pictures and post them in here once it gets installed.
 
Great, I kinda thought the same about the size, I don't know where there is enough room (at least in the engine bay). Maybe mount it in the trunk??? Or strap it in the passenger seat and put it's belt on LOL!!!
 
Well I got the pump installed today and all I can say is AMAZING! I ended up installing the pump on the power steering knuckle below the intake manifold. It was a tight fit but I ended putting a zip tie around it to hold it in place (Will likely rig up a bracket this winter to secure it to the firewall).

I wired the pump up to a spare fuse slot on the interior fuse box(15a fuse). I ran it to a switch that I will mount next tot he ratchet shifter. I can press the pedal as far as it will let me when the car is at idle, activate the pump, and the pedal will sink closer to the floor! I did one launch and the car didn't move an inch until I let off the brake!

I highly recommend this (@1990TSIAWDTALON ) for anyone with low vacuum because of cams. This is the best picture I can get of the pump installed, you can see the check valve close to the pump.

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Thanks. When I do this I will give you a PM shout, thanks for sharing for EVERYONE to be able to use. Great info for low vacuum cars! :thumb:
Nice diagram and follow up results!
 
I remounted the pump onto the firewall. I used a stock fuel filter mounting bracket and found a spot that I was able to mount the pump. I ended up mounting the pump upside down as that is how it seemed to fit the best, not sure if it will affect the life of the pump but the setup works great! Here is a picture of the new mounting location:

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@1990TSIAWDTALON
 
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