WOT switch for triggering second pump
11-19-2009, 10:56 AM
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WOT switch for triggering second pump Just an idea instead of using a hobbs switch... has anyone thought of using or used a WOT switch for turning on their second fuel pump? I can possibly adjust it to come on about 3/4 throttle because boost could start to spool up about that much throttle.
11-19-2009, 11:31 AM
#2
Boost referenced is really the only reliable way to go. Reason being, a well designed/responsive kit can build boost with 1/2 throttle or even less when the RPMs come up and the exhaust really begins to flow. Same is true under load in a gear or 2 down from 'optimum', get into throttle some and boost will come up quicker due to load on the motor.
11-19-2009, 07:56 PM
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11-19-2009, 08:05 PM
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two pumps doing the same work as one will run with less stress since youre not using them as hard. No more heat then you would have with a single working as much as it does alone. Its similar to alternator, they only supply the amount of fuel you need when called apond. I ran my twin intanks together with no issues. Ran good, no big current draw, nice cool fuel, hobbs switch is another thing that can fail and cause youre setup to get hurt. KISS method
11-19-2009, 10:57 PM
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i was always worried about two pumps at once, but its always a possibility.
i'll probably give the wot switch a try. i didnt want to utilize the hobbs because it would have been another hassle dealing with manifold vacuum/pressure and failing.
i'll probably give the wot switch a try. i didnt want to utilize the hobbs because it would have been another hassle dealing with manifold vacuum/pressure and failing.
11-19-2009, 11:03 PM
#10
I'm pretty sure running 2 pumps will still cause more heat. They may be working less but the fuel is still under the same pressure conditions. The only difference is now it's flowing more fuel to and from the tank on a return setup. Some experts claim that this will damage the fuel's octane level.
11-20-2009, 06:41 PM
#11
Bad info here....
2 pumps will definitely increase the heat.
Each pumps draws the same current no matter how many are running. 2 pumps equal twice the current draw since they are working against the regulator not the amount of fuel consumed. This just means twice the fuel is returned to the tank when 2 are running. A pump will draw the same current because it is still pumping the same volume of fuel through it. I've measured the amp draw, I know this is true.....
As for pump activation, you need to base it off of HP, which is directly related to boost levels. Going WOT off idle will not need the second pump in operation before the turbo spools. Depending on the regulator capability, activating the second pump too early may cause a pressure spike the could richen the engine & actually delay spool up.
2 pumps will definitely increase the heat.
Each pumps draws the same current no matter how many are running. 2 pumps equal twice the current draw since they are working against the regulator not the amount of fuel consumed. This just means twice the fuel is returned to the tank when 2 are running. A pump will draw the same current because it is still pumping the same volume of fuel through it. I've measured the amp draw, I know this is true.....
As for pump activation, you need to base it off of HP, which is directly related to boost levels. Going WOT off idle will not need the second pump in operation before the turbo spools. Depending on the regulator capability, activating the second pump too early may cause a pressure spike the could richen the engine & actually delay spool up.
