connecting vacuum pump relay

[rxl]

hi
wanted to upgrade to audi s2 d2 vacuum brakes and wanted to connect an electric vacuum pump.
any idea how to connect the pump so it does not run all the time?
any help would be apreciated.

[vit213]

operated by the ECU

http://www.volkspage.net/technik/ssp/ssp/SSP_257.pdf

it is necessary to make the control unit, using pressure sensor, for closed-loop control version.

[quattro-nick]

i think just connect the vacuumpump parallel on the vacuumhose en use a vacuum switch
some mercedes models use a extra vacuumpump like SLK compressor and some ML jeeps

[vit213]

SLK 230 KOMPRESSOR

pos 240 - vacuum pump
55 - brake control unit for vacuum pump

Typical aplication vacuum pump up28 hella - pressure sensor and ecu.

if turn on the pump constantly, it will burn down.

[Error404]

Vacuum pump is necessary IMHO

[rxl]

so i got hella pump and looked for information how to connect it. do i need an ecu or as some kits online only show a vacuum swith connected to it and a relay.

[pasbogdan]

An universal vacuum switch could do the job.Maybe an ajustable one.So it will close contact and feed the rellay coil with ground for example.