ss1

iTrader: (32)

Yeah, thats what I was thinking. It would be a cool idea if somebody could figure it out though. It would probably be more feasible with a sumped tank and external pumps.

ONEBADWS6

iTrader: (22)

I have been running the duel intank pump setup on all the time for over 5 years now. But I also have 78psi of fuel pressure lol.

BOTTLEFEDLS1Z

iTrader: (32)

Thank you!!!!!!

Racetronix

iTrader: (2)

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.

daniel6718

iTrader: (36)

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...??

Racetronix

iTrader: (2)

B/C the rating of the fuse required to run both pumps would in effect turn certain sections of the wiring harness and terminals into fuses themselves. The most vulnerable area would be in and around the gas tank.

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.

ulakovic22

iTrader: (12)

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?

MIGHTYMOUSE

iTrader: (59)

wide open switch, or window switch

there is probably a fuel pressure safety switch adjustable to the range which you run your fuel presure at that would fit the bill, just have to look around.

ulakovic22

iTrader: (12)

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?

MIGHTYMOUSE

iTrader: (59)

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.

Racetronix

iTrader: (2)

As others have stated your options are:

- 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.

98Camarod

iTrader: (43)

Am I thinking of the wrong thing here? If you hotwire the two pumps to operate at the same time, won't you have to much fp? There is supposed to be 58psi. Will this cause you to run rich or am I retarded? Can someone shed some light on this for me?

Racetronix

iTrader: (2)

Under partial throttle this would be a problem hence the controls mentioned above.

98Camarod

iTrader: (43)

Thats what I was thinking, but what about the people that are running them full time? Also on the hobbs switch how do you operate it off of throttle or vacuum? It doesn't look like there is anything that would allow it to function.

Lonnies Performance

iTrader: (16)

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.

zapp168

iTrader: (7)

I initally ran two pumps together and noticed very little if any difference in my AFR at lower RPM's. The regulator kept the pressure steady, there was just more volume at higher RPM's

Racetronix

iTrader: (2)

What type of return system are you running?

7845

iTrader: (1)

i run two pumps all the time and my fuelpressure is steady and havent had any issues with tunning for AFR

Racetronix

iTrader: (2)

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.

zapp168

iTrader: (7)

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?