hey guys I'm going to be running dual supra fuel pumps. I know its a little overkill but just want to be sure I have enough fuel supplying the engine. I've got 850 pri. and 1300 sec. using the hard line from the charcoal canister as another fuel line, the pri and sec rails have their own fuel lines and are regulated by an aeromotive FPR. going with some in-line filters also, what kind should I get?

so how do I wire my pumps? I wanted to have some type of switch as a safety device, this would turn on the pumps and would be hooked up to a led light to tell me their activated. you know the kind with the red cap over it. can I just run a wire from the battery with a fuse in-line, then the switch then the pumps.....

does any of this make sense to you guys?

thanks guys, Matt

 

^^^^^^^

 

i'm wondering the same thing, so bumpidy bump.

 

bump

 

check out the last post in this thread

https://www.rx7club.com/forum/showth...al+supra+pumps

 

maybe the girl in your avatar can help?

 

snook....

I read that a few days ago, it does make sense to me, but don't I need to upgrade my wiring too? I was thinking of wiring the pumps to turn on manually. I'd simply take a power cord run it to a switch then to the pumps. Or I could take that same Idea and run the power to only one pump. Kind of like an auxiliary pump. would I need to put some kind of check valve in the fuel lines to prevent pressure pushing on the pump that's not operational? I could run the supra pump all the time then turn on the stock one for extra safety. or run the stock one to the pri. rail and the supra to the sec. rail.

what do you guys think....

93 r1... I asked that girl in my avatar what she thought. she told me to ask yours.

 

I just had that same problem. I am installing a T51, and now running 850 1600 setup. Here is waht I did. First I am running the walbro with a stock pump. I used a t fitting and spliced them together. I am running the walbro on the stock circut, and hard wired the stock pump directly to the battery, with a switch, and a fuse. When I am not running at the track I will have the stock pump off, and when boosting I will have the stock pump on. Not tested yet, but I am confident it will work. Probally sounds pretty dumb, but it is worth a shot.

 

lerch, that is what I'm going to do, except with a supra pump running constant. then flip the stock one on for a little extra power. how do you know what voltage they are getting?

matt

 

The stock one will be getting a full 12 volts, and the other will depend on engine load. I think under normal driving it will only see about 6 volts, and high load demands the relay will increase the voltage.

 

so if I plug the supar one into the stock harness it will get 12 volts?

 

It will not be a constant 12 volts.

 

i contemplated digging up an old thread or starting an old one...well, here's an oldie for you...

I am planning to run a stock pump with my supra pump. guess I just need photos and a write up...

Also, why would you want to turn the stocker off during daily driving and not just wire them together with a higher gauge wire and run them both on full time?

EDIT: Does it change your fuel pressure when you add an additional pump?

 

yes big time...
Im running 2 supra pumps now. Hardwire both to the battery with a 30 amp fuse and 30 amp relay for each and you're done.

 

What size fittings should I go with...and also what gaue wire? Is there something wrong with using the same stock power source for both pumps?

Thanks in advance.

 

The FPR should really be in complete control of the pressure unless you either have too much pump and the return line becomes a restriction (high pressure at idle) or if you have too little pump and pressure drops when the pump can't supply enough fuel to maintain the pressure the FPR wants (like under high boost and pressure). But if everything is sized appropriately, the FPR should be in control of the pressure. Otherwise, your fuel pressure (and thus tuning) would change with the electrical load, making the car very difficult (impossible) to tune.

-Max

 

I'm going to rewire mine with 10 gauge wire that I got from an audio shop for high current amps

use a 30 amp relay with a 30 amp fuse in a fuse holder that is rated much higher like 80 or so...

There is a problem with using one power source for both pumps because right now I'm running 1 wire with 1 30 amp relay and 1 30 amp fuse and it has melted about 1 time per month. Each supra pump draws 20 amps. The most confusing deal about this is how to get the wiring down into the fuel assemly safely...

 

yea I guess I didn't answer the question completely. What I meant was that my base pressure went from 40 to 62 when I put in 2 supra pumps instead of 1 m2 boshe pump

 

So do you guys think that running a supra pump and a stock pump together would be a problem, or do I need to run two identical pumps?

Max, so what is everyone doing to counteract the problems you mentioned? What are the optimum sizes for a supra pump and a stock pump? Wouldn't the stock lines be sufficient?

 

Find a rubber grommet that the wire just fits into, then drill the appropriate hole for the grommet, install grommet and the wire should make an air-tight seal, if not just use some silicone.

 

there is a problem with that as well
the fuel pressure is forcing gas under the protective covering of the wires and forcing fuel outside of the fuel tank....you need to use an electrical bulkhead fitting so theres not actually wires going in and out of the tank.

 

Did you ever figure this out. i finally have my second pump and ready to install...While I have the assembly out I will go ahead and upgrade the stock wiring. As I thought about the gromet with the wire deal you replied with the fuel pressure in the tank so I am now at a loss with what to do. There's no rush for me to install this so I rather figure it out completely before I go ahead...Shouldn't be that hard, I'm sure there's quite a few on here running duals...Think I will start a thread requesting setup options from people with dual pumps.

 

First off, I would be SURE that a single pump can't do the job you need it to do. Two pumps more than doubles your failure points - the various hoses connecting them, the extra wiring, and the fact that one of the pumps could, in theory, fail.

I would either run a Walbro pump with a good 12v power source, or a good Nippondenso pump (Supra, Cosmo, etc.) with a Kenne-Bell Boost-a-Pump - that can step up the voltage to the pump under boost (running it over 12v) so you get more out of the pump. The Walbro doesn't do well with increased voltage, but it DOES flow a TON of fuel at 12-13 volts.

As far as wiring, the safest way is to use the stock fuel pump wiring for your "on" signal. The ECU will shut the pump off if the engine isn't running, which is a VERY good idea in case of a wreck - otherwise you could have a pump running after a wreck, pumping fuel at 40psi into a fire.

Run a decent-gauge (12 gauge would be fine for most any single pump) wire from the positive terminal of the battery back to the hatch. Make sure to put the fuse in the power wire fairly close to the battery terminal! Get a relay, use the stock fuel pump wire to switch the relay on, and have the new wire be switched by the relay. You can use the wiring to the fuel pump from just ouside the tank - that should do the job just fine.

I ran a similar setup in my TII for YEARS with no problems, always had battery voltage at the fuel pump, even with a full electrical load on.

If you do need to run 2 fuel pumps, I'd go with 10 gauge wiring, but do the same routine with the relay and everything - just make sure the relay is rated for the amount of current that's going through it. You will most likely need to run the big wire into the fuel tank - that would mean drilling a hole at the top of the fuel pump assembly, grommeting the hole, and running the wire through, then thoroughly covering with RTV to keep it sealed.

I'd also hit up Supraforums - many of the Supra guys have "been there, done that" on dual pump setups, and I'm sure they've found all the ins and outs of dual fuel pumps by now.

Dale

 

yea blue you use an electrical bulkhead fitting. Im about to make some for myself because I cant find what im looking for

Heres the idea and you put a circle connector on the inside of the tank and one on top of the fuel assembly that way theres no wires running in and out of the tank its pressure tight.

 

Thanks guys. I am not SURE that my one pump (currnetly running supra pump) will do what I want it to. Will tune to 18psi on pump gas sometime in the next couple months. Probably will go ahead and upgrade the stock wires to a thicker gauge to start with.