Has anybody sourced one of these pressure switches from spa bath suppliers...I've rung up a couple of places but they seem to say most of theirs work with water. I'll let you know how I go...I don't know much about spas
Thanks
Quote:
A suitable pressure switch is an adjustable Hobbs unit (pictured), available from auto instrument suppliers. However, this switch is relatively expensive and a cheaper unit is easily found. Spa bath suppliers stock a pressure-operated switch that is ideal for forced aspirated car use. The pressure switch is designed to work as part of the air-actuated switching system which is used in a spa bath so that bathers don't have to directly operate high voltage switches. The switch triggers at around 1 psi and costs about half that of a traditional automotive pressure switch. If a switching pressure above 1 psi is required, simply tee a variable bleed into the pressure line leading to the switch. Adjusting the amount of bleed will change the switch-on point.
Location: tallahassee FL usOFa
Registered: May 2002
Re: Sourcing Pressure switches - Hobbs alternative
Mon, 12 July 2004 13:27
i don't have a clue what kind of application you're looking for, but how about an oil pressure switch that will usually ground at 10psi or less, or a hydraulic type brake light switch that will have 2 contacts and be open at about 10psi or less.
ask for one for any old car - the VW air cooled ones are pretty common.
Re: Sourcing Pressure switches - Hobbs alternative
Mon, 12 July 2004 20:04
It's to detect manifold pressure and activate another injector. Thanks for the ideas. I'm not sure on how pressure switches compare that are desinged for different operating gases/liquids.
Re: Sourcing Pressure switches - Hobbs alternative
Wed, 14 July 2004 09:54
Alrihgt - just a quickie.
If I want this switch to switch on an injector as soon as any boost is detected I would need a 15psi hobbs switch t to come on just around the point where pressure is above atmospheric? right?
I'm just getting confused because this article below talks about an already turbod car that only needs the extra injector if running above 14.7psi boost..but then he recommends the 15psi hobbs switch (adjustable 14-24 psi)..does this mean he'd have to adjust to about 20 or so psi for his application if what he says is true.
I see Hobbs switches that are 2psi also, what would these be good for, as someone on ebay is selling then for automotive stuff?
Is the 15psi the one people use when they fit a turbo to a NA car and want to switch extra injector.
Mon, 12 July 2004 12:30
