26psi ,single walbro, rc 1000 , idc 87%

 

Really boost pressure is almost a useless statistic (I used it too) as there are way too many other variables involved. Power output would be a more consistent benchmark, but not everybody dynos their car. Also, dynos don't all read the same as shown by people ranging anywhere from 420whp (me) to high 400- low 500whp range. Maybe those people modified their pumps or got lucky on the particular one they received or they have a high reading dyno.

On a green you will probably be fine on a single pump, but you will only know for sure if you try. Just watch that a/f ratio and let off if you go lean. Also if you can log do so and watch your injector duty cycle.

 

bottom line is NO, you do NOT have to have a double pump.

BUT you may find that the single pump MAY NOT push the fuel you need running high boost. if that's the case, then oh well, just stop there until you can get a double pumper.

 

Thanks for all the input

 

33 psi, green, 1450cc, single walbro, e85. My car goes lean on the top end. I NEED and more fuel.

 

Could you just take out the white plastic piece than show in the picture inside of the red circle? what it's for?

 

The device you are looking at is what pulls the fuel from the right saddle tank. Without it you will not be able to use your fuel in the right side fuel tank.
Don

 

It’s what I figure out, I upgrade to double pump and I just drill a hole to get better flow, but I didn’t know that was for that! Do you know the name of that part? Do you know what else can i use to replace it?

 

How it works?

 

It's a gravity syphon. The level on the driver side gets lower than the passenger side and it levels the two sides out. The line that Ys into it is the fuel return from the engine bay, which is just excess fuel that your engine didn't use.

 

You are on the right track. But it is called Bernoulli's principle. Which in laymen's terms means to siphon. It works the same as a carburetor venturi. The only difference is this fuel tank device relies on fluid instead of air being drawn through to create the siphon.

Don

 

its also called an venturi pump
http://en.wikipedia.org/wiki/Venturi_pump

Its an rough explanation.

The Evo venturi is fed from the fuel return line, creating a slight vacuum at the "bridge" line to the passenger side fuel tank. Thats the reason that you might see that the fuel level gauge going down fast from 1/2 to 1/4 when running WOT for longer time, because the return will not feed enough to "pump" over right to left.
After slow down, the Fuel lever rises again because more fuel will be transfered to the Pump assembly. ( very common here in Germany during longer full speed Highway driving )

Also an advice:
DO NOT LET THE Venturi assembly facing direct to the Fuel socks!!
If the right side Fuel tank is empty ( Level showed is app. 1/4 to 1/3) , the return fuel will be mixed with air bubbles. So the density of the fuel will be lower and the tune get out of hand. Thats the reason why on the stock unit there is an cap over the venturi, so the bubbles will not feed to the socks. On Double pumpers, its possible to add an piece of stainless sheet metal ( very thin ) to one of the pumps ( with an clamp ) which forces the bubbles to move away from the socks.

I had it a few times after installing the Double pumper, that it was going leaner for no reason when the level was below 1/4. Then i researched the mistake,and found it right there.

 

Thanks to every one, i have fix it already, but after install my Full Blown Walbro Dual Pump i have the pressure hose (-8AN) heat up, my return line is -6AN, any idea why this happen?

thanks

 

If you wanted a bigger single you could always get one of the new DW300's or the Aeromotive 340's and get a bit more then a Walboro 255.

 

yes but i have two walbro 255 running all the time, i have enough fuel for what i need, my problem is than the pressure hose is heating up close to the fuel tank