Hobbs Switch For Boost Control?

[RS12Turbo]

Anyone familiar with these? I read online that you can use one in conjunction with a MBC. Set the MBC to over boost, say 18psi, then have the hobbs switch set to your desired boost, say 13psi. From what I gathered, you'll spool up quicker because the mbc is set higher, but the hobbs switch keeps it from over boosting.

I was wondering if you could just use the hobbs switch without a boost controller, and just set it to your desired boost, in conjunction with a toggle switch turned on, then with a toggle switch turned off, you'll just make stock boost. Will it work this way as well?I've seen them on Ebay with 2 vac ports like this one http://cgi.ebay.com/ebaymotors...ZWDVWand also with 1 vac port like this one.http://cgi.ebay.com/ebaymotors...ZWDVW

[iliketocrash]

i'm guessing there is more to this because a hobbs switch is simply a pressure activated switch. you still have to have the switch control something else. the only thing i can think of off hand is to have a selenoid between the boost controller and its vaccum source and then have the hobbs switch set to control the selenoid. but if you set the manual boost controller to a higher boost than what you actually want then it will still boost to whatever you have the mbc set to. so if this is the method in question then simply set the mbc to your desired boost level and then set the hobbs switch to open the selenoid at 3 or so psi below your desired boost. unfortunately there are inherent problems with the overall setup or else mainstream electronic boost controllers would be obsolete because this method is real cheap and easy =)

[float_6969]

We use hobbs style switches quite frequently in the pool and spa industry and the problem is that they are a relatively slowly reacting switch. For our applications they work fine, but in an automotive application, they slow response time would equal over boost and unstable boost levels.