duel intank hot wired vs hobb switch
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the trigger wire goes hot when my tps criteria is met for the second pump. this power trips and holds the relay closed feeding power to my pump. T power off of that trigger wire to the led and ground the other wire of the led.
when the relay is being triggered your led will be lit. i also look for the fuel pressure to jump.
if your trigger wire is a ground, you can do the same thing, just give the other leg of the led switched power.
when the relay is being triggered your led will be lit. i also look for the fuel pressure to jump.
if your trigger wire is a ground, you can do the same thing, just give the other leg of the led switched power.
Thank you!!!!!!
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Our F99 harness has no problem supporting the current demand of two pumps b/c our design is overkill.
It has to do with having two separate fused circuits in the correct location should anything go wrong with one pump. There is also the redundancy issue when dealing with high-HP applications.
It has to do with having two separate fused circuits in the correct location should anything go wrong with one pump. There is also the redundancy issue when dealing with high-HP applications.
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#25
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Our F99 harness has no problem supporting the current demand of two pumps b/c our design is overkill.
It has to do with having two separate fused circuits in the correct location should anything go wrong with one pump. There is also the redundancy issue when dealing with high-HP applications.
It has to do with having two separate fused circuits in the correct location should anything go wrong with one pump. There is also the redundancy issue when dealing with high-HP applications.
but if it will support 2 pumps then why dont people run both off of 1 wire then if something goes wrong with one then the car will die basically and keep you from poping the motor incase you happen to not look at your fuel pressure during a run...??
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i didnt catch onto that...mayb its just late
but if it will support 2 pumps then why dont people run both off of 1 wire then if something goes wrong with one then the car will die basically and keep you from poping the motor incase you happen to not look at your fuel pressure during a run...??
but if it will support 2 pumps then why dont people run both off of 1 wire then if something goes wrong with one then the car will die basically and keep you from poping the motor incase you happen to not look at your fuel pressure during a run...??
There is a right way and a wrong way to go about wiring things. Any deviation from our DP harness design would be a compromise in safety and performance.
It is best to have two dedicated fused circuits for each pump. The side benefit is not having to run both pumps all the time which draws double the power and heats the fuel much more quickly.
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A lot of people who run dual pumps are FI so running a Hobbs switch is fairly simple, but what about those that are running N/A at that power level? I'm running a 555 BBC and am right at the threshold of needing more fual than one pump, but don't want to run 2 all the time. Is there something I can hook up that will kick the 2nd pump on if my fuel pressure drops below a preset mark?
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Am I on the right track in terms of using fuel pressure to dictate the 2nd pump? Can I run both a FPSS and an armed nitrous system to turn on the second pump or is it one or the other?
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its definitely a feasable option. keep in mind that for the second pump to cut on, your fuel pressure would all ready be dropping which is bad in general. if you just trigger it at wide open or at a certain rpm it will never get a chance to drop.
you can run any number of switches in series to trip the relay sure.
you can run any number of switches in series to trip the relay sure.
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A lot of people who run dual pumps are FI so running a Hobbs switch is fairly simple, but what about those that are running N/A at that power level? I'm running a 555 BBC and am right at the threshold of needing more fual than one pump, but don't want to run 2 all the time. Is there something I can hook up that will kick the 2nd pump on if my fuel pressure drops below a preset mark?
- throttle switch
- vacuum switch
- fuel pressure switch
Our DP harness has provision for any of these types of controls for both pump circuits. This allows you to alternate primary and secondary pumps for even run time and testing purposes.
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#33
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Under partial throttle this would be a problem hence the controls mentioned above.
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#35
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Typically the hobbs is for boosted applications.
I provide a separate arming switch for nitrous cars that activates the nitrous system & the second pump all with 1 switch. This is suitable for a car that can run motor only on 1 pump.
For N/A applications on cars that need more than 1 pump on motor only, I recommend a rpm activated switch in conjunction with a full throttle switch. This way there is no unnecessary cycling of the pump at part throttle, nor do you have to deal with a pressure spike by bringing on the pump too early.
Obviously you can argue that any additional component is more prone to failure, but so is the MAP sensor, the TPS, 2 nitrous solenoids etc... any of which could cause engine damage. The biggest problem seems to be either cheap components or questionable installation methods. This is why I deal with Racetronix, as there components are top quality. I have done hundreds of these without a single pump failure.
Do it right... do it once.
I provide a separate arming switch for nitrous cars that activates the nitrous system & the second pump all with 1 switch. This is suitable for a car that can run motor only on 1 pump.
For N/A applications on cars that need more than 1 pump on motor only, I recommend a rpm activated switch in conjunction with a full throttle switch. This way there is no unnecessary cycling of the pump at part throttle, nor do you have to deal with a pressure spike by bringing on the pump too early.
Obviously you can argue that any additional component is more prone to failure, but so is the MAP sensor, the TPS, 2 nitrous solenoids etc... any of which could cause engine damage. The biggest problem seems to be either cheap components or questionable installation methods. This is why I deal with Racetronix, as there components are top quality. I have done hundreds of these without a single pump failure.
Do it right... do it once.
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What type of return system are you running?
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#39
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Running two in-tank pumps with the factory F99 return system will cause a pressure rise under light to moderate throttle upwards of 70+PSI.
The factory return system is unable to relive the extra volume of fuel b/c the lines are too small.
The factory return system is unable to relive the extra volume of fuel b/c the lines are too small.
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I am not sure of the "number" of my system (F99?) It is the factory 98 F-body system with rails. Before the Hobbs switch was installed I just hooked up the second pump to constant power to test it out, the car did not fall on it's face so I know the two pumps were working, but the AFR gauge did not seem to fluctuate much with the second pump, Small amount yes, but it did not seem like it was constantly rich. YES I need to get a FP gauge for inside the car, and I did only drive the car once that way. You are probably right....but nothing jumped out at me?