That would be really good info.... A lot of time on your hands I guess can be good or bad. Hope its good in your case.

 

Problem there would be liability.
If something went wrong, fuel could make it's way into the passenger compartment. Good idea though just a packaging problem.

 

now, I am stumped! I wonder what the problem was. One of my other curiosities was that as soon as I would turn off the car, my fuel pressure would drop to around 13 psi.

now, my fuel pressure stays in the 40psi range when I shut the car off. I don't know what it does a few hours later, though. What should it do? should the fuel system hold it's pressure when the car is off or will it usually leak down to a low pressure?

 

The fuel system shoudl hold pressure over a short duration of time. If pressure was dropping to 13psi quickly there is a leak in the system. Could have been a bad o-ring on the pump or the pump failing internally.

 

Not so good in my case, but could end up being a good thing for the Z/G community.

 

My car holds pressure for quite a while after shutdown. For isntance went to the gas station this morning. Had ~50 PSI of fuel pressure at time if shut off. After turning the motor off I put the key back in (turns gauges on) but didn't prime the pump. Fuel pressure showed 40 PSI. Pumped gas took keys out to get reciept from in store. Got back into car, put keys in (turned gauges on again) still 40 PSI. Turned key which primed the pump fuel pressure went up a little then settled at 40 PSI again. After start up back to ~50 PSI.

 

Well hope it works out for you. I'm always for community benefit but you gotta take care of #1 first you know.

 

i think the pump was failing internally.

the old pump was pumping out about 35-40%% less fuel at idle over a one minute interval than the new pump. I didn't check to see what the voltage while idling was either. At a higher voltage, (with the engine turning more than 700 rpms ) the newer pump probably would have out pumped the old one by an even larger margin.

 

Yeah I've thought of that too. But if you think about messing up the fuel assembly oring or stripping the mounting bolts could cause the same thing at fill up. But you are correct running a pump in that area would mean more potential failure point which could lead to fuel in the passenger compartment. Hmm, I wonder if I could fab up some kind of catch tray in case of fuel spill that dumped out under the car or something. I don't know. Theres just not that much room anywhere for it and I don't like putting a pump and surge tank right where the exhaust piping is. Espeically as a road hazard here in Socal...

 

Well you could always guinea pig the Bosch unit UnderPressure mentioned..

 

Patience, patience... Give me a little time to come up w/ something.

 

someone just needs to fab up an in-tank pickup so you can feed an aeromotive A1000 or similar pump (weldon anyone??? ) yo'd still have to have a retunr fitting that connects to the siphon jet so that you can pull fuel from the driver's side saddle tank. It would seem pretty easy to accomplish.

 

Oh I'm not trying to rush it. I just figured if he has to do something now he might as well do the Bosch unit.

 

Aeromotive ranks right there w/ Walbro as far as i'm concerned. Way optimistic ratings on the pumps outputs. Seen them give out @ 600-750whp on mustangs when they are 'suppose' to be rated to 1200+.

Weldons would works very well, but who would put up w/ the noise on a daily basis? I think the 044 might be a good alternative. But there are a couple other options out there as well...

 

Well hell if your gonna do a BUNCH of fab miht as well design a whole new fuel tank and pump assembly What would be REALLY interesting is if someone could set up a dual pump feed with one pump pulling fuel from the passenger side and one pulling fuel from the drivers side of the tank feeding a surge tank and the rails and then dump the return fuel back into the same sides of the tank.

 

a quick drop in fuel pressure is a tell tale sign of a fuel system failure.
i have been running my designed fuel system for almost 2 years now with not a single hiccup. super simple, keep the stock assembly without mods, then make new feed line with an inline pump. the stock pump will be in freeflow with the inline larger pump creating the pressure. nothing has to happen to the stock fuel pump assembly at all, other than drilling for your return line. pretty much the same as the aam set up, but no surge tank. the fuel pump sizing is the key to making it work.

 

I'd be interested in researching pulling fuel via 2 pumps from the two sides of the tank individually. I know the crossover tube to bring fuel from the drivers side to the passenger side is pretty small and is part of the issue with running low on fuel with a high flow pump... I'd be curious to see if seperating the feeds from the each side would do anything to imporve that... But I am by no means a fuel system guru. I've played with fuel stuff before but would leave this kind of research and design to someone more versed in this kind of stuff.

 

The Bosch 044 pump is the cats pajamas of intank fuel pumps. I have used them in Vipers before, but unfortunatly there is no-way no-how you will get one to fit in the 350z fuel pump assembly.

The issue with building custom fuel pump assemblies for the 350z/G35 are the fact that you have a open tank with no baffles, and it has a saddle shape due to the driveshaft.

You have to put your pump(s) on one side, and you have to have some type of siphon to draw fuel from the opposite side to the pump side. Lastly, you have to have a surge tank on the pump side so that the pumps have fuel to pump when your not at a full tank and you floor it or turn hard and all the gas shifts to one side of the tank.

Utilizing the 044 pump would require a totaly custom surge tank and mounting assembly, which is FOR SURE possible. You just have to do make a venturi where the return fuel will draw the drivers side fuel to the passenger side. But of course, that is the part that most people have no idea how to do.

The other problem is keeping the surge tank full. You would end up with little options, and something that is sort of like the APS twin pump assembly, just a can with a pump in it. You can either put a hole in the bottom of the can and loose its functionality under high G loads and lower gastank levels, or you can keep it closed at the bottom and deal with the inability to use all the gas in the tank and therefore still needing to fill up before empty if you plan on racing without above 1/4 tank. The final solution is to entirely reengineering the factory setup out of billet or something that uses another return powered venturi to fill the surge tank at all times.

Walbro has a very special model of the 255 that most people havent seen, and its just so perfect for what we need to do for higher HP levels that I couldnt pass it up.

Personally I have never had a walbro fail, but I guess if its happening its happening, and I am sorry to hear that it is because they are just so damn cheap and powerful.

 

The only way you could do this would be to put a balance tube under the driveshaft that keeps both sides of the tank level at both times. IF you did that, all problems would be solved and you could run a stock 350z assembly on both sides of the tank, as it will bolt right into both sides (as long as you swap the potentiometer chip in the level sensor for drivers side).

The only problem with this, is that I dont think most people would approve of driveshaft loop that is made out of out a hose or pipe connecting two sides of the gas tank!!!

 

Charles,

Is this the "high pressure" 255 unit?it is designed to have high flow rates even at higher fuel pressures.