Monty

Where can I buy these? If you're in Chicago and know of a local source, I'd appreciate it. Thanks!

B4Ctom1

NX, NOS, etc

Monty

Thanks, I just looked in the NOS catalog, the only one that would fit my situation(normally open circuit) had a 7psi fixed pressure point. I was looking for something adjustable, or fixed in the 2-5 psi range. At 7 psi, I've already surpassed the rating for one of the Aeromotive A1000 pumps and need the second to already be energized.

Anyone know of a normally open circuit Hobb's switch that switches at 2-5psi?

SATURN5

Stewart Warner has a large selection...
http://www.stewartwarner.com/Catalog/swpres.html

Single Circuit / 2 Terminal - Series 5000 Switches (top) Kit Factory Set-Point Characteristics Compatible Part Number
78628 1 psi Normally open
78632 1 psi Normally closed
76051 2 psi Normally open
76061 2 psi Normally closed
76575 4 psi Normally open M4006
76577 4 psi Normally closed M4007
76576 10 psi Normally open
76578 10 psi Normally closed
76052 15 psi Normally open M4008
76062 15 psi Normally closed M4009
76053 35 psi Normally open
76063 35 psi Normally closed
76054 60 psi Normally open M4010
76064 60 psi Normally closed M4011
76055 100 psi Normally open 14732
76065 100 psi Normally closed 14723

Dan W

I wonder if just a simple WOT switch would work.

Monty

Saturn5, thank you very much, exactly what I was looking for.

DanW, that might work as well. If the Hobbs switch doesn't work out, a WOT contact swtich might do the trick too. Thanks.

BlownBird

Monty,
The FAST system you are running has a NO2 activation feature (2 stages I believe). Would it be possible to use this feature to fire the relay for your second pump at a set rpm? Might be something worth looking into, you may be able to activate it at a given PSI using the MAP. Just a thought, Don B.

Monty

No that's a darned good idea I hadn't even thought of. I will definitely look into that.

Dan W

I was thinking the same thing the other night. I'm running DFI gen VII and the NOS activation is based on TPS vs RPM... there is also a field for "delay time". Unfortunatly its not MAP based but it would probably work as well as a WOT switch with a little bit of work.

Does the FAST system work the same way Monty?

Monty

I have not used the NOS funtionality in the FAST yet, so I'm not really familiar with it.

I just took a look at the NOS menu and parameters, it allows for up to 4 stages of NOS. It has a TPS Enable Threshhold (%), Min RPM for Activation, individual delays for each stage of NOS (2nd, 3rd, 4th)Target NOS A/F ratio, individual retard for each stae, and 4th stage fuel enrichment.

I believe the lead for the NOS control is a negative ground, meaning that the ECM close the ground circuit. I had initially thought about using the Hobb's switch in the 12v switched circuit for the fuel pump controller and second pump. That way when boost reached 2-4psi, the second fuel pump controller and pump would be turned on. I could do the same thing with the FAST NOS control by using the ground lead to activate a relay to control the 12v switched power to the fuel pump controller. This would probably work equally as well since I could activate it based on the combination of throttle position and rpm.

I might as well do it that way, because the new FAST system that's coming out has fuel pump control even with WBO2, Sequential, and ICC unlike the current system. No point in creating a seperate fuel pump activation circuit if I don't have to. I have also heard that the new system will have 2-4 user programmable outputs that could be used for something like this, as well as wastegate control, etc. I don't know when it's coming out though, I just know it's still in Beta.