which hobbs switch?

[spooledstang]

I was at NAPA and they have a hobbs switch that turns on a 4psi, and one for 10psi. Apparently these are adjustable. (?) I want a turn on point of 6-7psi for my turbo mustang. Which switch do I use, and how far is the adjustability range? This is a budget project, so progressive controllers are out. Thanks.

 

[turbogto]

Funny, I was just on the Hobbs website:

http://content.honeywell.com/sensing/hss/hobbscorp/catswitch4.asp

According to them, the 4 psi can go 3.1 - 7psi and the 10 psi can go 8 - 13 psi.

I'll bet the 4 will go to 8 and will probably cover you. I've messed with these quite a bit and they have a pretty good range of adjustment.

They like air and gas but not alky or water, or so it seems. Still trying to get a definite answer from them on that.

 

[salvageV6]

It's a boost switch.

You only put air into them.

No reason to pump alky. or water into them...

 

[turbogto]

Yeah, I know that was SpooledStang's question, but it sounded like he hadn't used a Hobbs before and there are applications where pressure switches do see alcohol so I was just trying to give him some extra info.

Last I checked all of SMC's kits have an alky compatible electric pressure switch that turns on the alky light on the SMC controller at about 30 psi.

SMC's switch has a much wider range of adjustment than the Hobbs, but isn't as precise as the Hobbs as far as what psi it goes on and off.

As far as I know this is the only Alky compatible electric pressure switch at a reasonable price.

In my case, I'm using NOS with Alky enrichment and I want to use something to kill the NOS if the Alky pressure drops off for some reason.

Initially I didn't want to just use a pressure switch set at 30 psi to allow the NOS to flow because the alky uses a boost referenced pressure regulator that I was planning to start out around 15 psi and I wanted to bring in the NOS at low boost to spool the turbo...it gets complicated.

 

[spooledstang]

good stuff! looks like i'll get the 4psi switch.

 

[turbogto]

Hobbs Update

OK, have fun!

BTW: Got an answer from Hobbs and their switches ARE Alky compatible:


From: "Turnbull, Tom (IL29)" <Tom.Turnbull@Honeywell.com> Add to Address Book
To: "'turbogto@yahoo.com'" <turbogto@yahoo.com>
Subject: RE: Hobbs Corporation Website Feedback
Date: Tue, 24 Feb 2004 12:16:07 -0700


The o ring and diaphragm are compatible with alcohol.

Best Regards,

Tom Turnbull
Global Product Manager
Ph 217-753-7791
Fax 217-753-7789
email: Tom.Turnbull@honeywell.com


-----Original Message-----
From: Gustafson, Amy (IL29)
Sent: Monday, February 23, 2004 8:41 AM
To: Turnbull, Tom (IL29)
Subject: FW: Hobbs Corporation Website Feedback


-----Original Message-----
From: turbogto@yahoo.com [mailto:turbogto@yahoo.com]
Sent: Sunday, February 22, 2004 8:33 PM
To: Hobbs Corporation Website Feedback
Subject: Hobbs Corporation Website Feedback

Your inquiry is - 1_Urgent_Request
Comments and Questions

Dear Hobbs Engineering,

Can you tell me if the Hobbs pressure switches sold thru Napa stores can handle alcohol as the pressurized fluid??

If not, what can I do??

Thanks

Pete
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End of Form Information