Trying to come up with the best way to overcome the fuel supply issues with high hp demands.
Has anyone experemented with puting another Nissan pump assembley in the drivers side, runing it through a relay so you wouldn't pull volts from the passanger pump.
Takeing the outputs from the pumps run them into a Tee to feed the raills.
Take the return from the regulator, split and feed one to the drivers and one to the passangers side.
I would think the syphon would not be needed any more if the 2 pumps are pulling from both the driver and passanger side?
This seams like much too easy of a fix for the single Walbro runing out of steam. Does anyone have any experence with this?
Kevin

 

The only thing that I thought of while reading the post was interference of some sort. I would think that you'd have to keep the lines separate and have separate ending points.....

 

I asked phunk about this a while back and he listed some reasons why it wouldn't work. I'd have to find the post but it was quite a few months ago I think.

 

I ask him this too but, I can't remember what he said! I thought it was because of the return from the regulator only going to one side, but if you Tee it to right and left? Charles?

 

Any thoughts?

 

The main problems that phunk stated that I can remember are

-problems with return line
-syphon system not working properly
-fuel starvation at low levels and high G situations
-one pump running dry before the other

I would just wait for his twin pump setup that replaces the stock unit. Will be the easiest and probly best solution other then going with a fuel cell, which is what I ended up doing.

Edit: Thought you tried the fix already. I would do that first.

 

Kevin, did you see me AAM Stage II fuel fix I posted about? Remember, we talked about returning the fuel back to the surge....it work!! Just havent tested it on the track, but I have very stable fuel pressure on the dyno.

 

Did you weld on another fitting on the surge, or tee the walbro and the return from the reg. together?
So I would think you ran the overflow from the surge back to the fuel box to run the syphon? right?

 

Tig welded another fitting onto the surge tank.

 

The only time the syphon run is when the surge overflows?

 

Correct, which will be most of the time. Just one more reason to keep that tank at 1/4 or above before beating on the car.

 

It seams like a good plan. Did you leave all the interninal of the modified return housing just like it was still returning from the regulaor?

 

Sharif, I was talking with Kevin earlier today and the only potential problem I see with returning directly to the surge tank is fuel temp. With that small of surge the fuel will become very hot as it feeds and then returns to that small of a tank. This could lead to "pre-detonation". I think it would probably be okay at the dragstrip with cool down time and for street driving. But I think it could be a major problem on a road course. In order to properly run that type of set-up I would think you would need a much larger surge tank which might lead to a whole new set of variables. Jason

 

The surge is constantly going to be circulating the "hot" fuel back to the main fuel tank under most conditions. Only under extreme loads, will the return to the tank run very slowly...or stop.

But you have a good point, and a potential issue, depending on how hard the car is driven. We thought of using a fuel cooler inline. Jeff at Evan's Tuning uses them on his 7 and 8 second Hondas with very good results, so might be worth looking at.