Hi Guys,

I've installed a surge tank on my Civic and I have a question maybe you can help .

From the OEM fuel tank , I have an intank walbro255hp that is feeding the surge tank
The outlet from the surge tank is -10 feed to an Aeromotive A1000 fuel pump,then goes -10
to a -10 fuel rail and to the Aeromotive fpr and the return is -6 to the surge tank again.

With the system I have,can the surge tank be without fuel?
Sometimes I can hear the Aeromotive fuel pump change noises.

Thanks for your help

 

Any help please

 

you need to return the surge tank to fuel tank of the car. also, you should probably put a pressure gauge on the tank to make sure it has adequate pressure. too much could cause a problem, not enough and you aren't taking full advantage of having a surge tank. 2-6 psi is ideal. You'll probably have to install a check valve in the return to the tank to achieve this though.

I would think it'd be next to impossible to empty the surge tank entirely unless you are making crazy power and did like a 3 mile pull.....haha.

 

Thanks for your reply.

I have a return from the surge tank to the oem fuel tank

About the 3 mile pull , no I use it for the strip only, so 400m pull

 

At 0 psi, your Walbro 255 is flowing approx. 510 lb/hr
At 50 psi, your Aeromotive is flowing approx. 560 lb/hr

That's a 50 lb/hr discrepancy.

So if your rail pressure is set for 45 or 50 psi, the aeromotive could very well be sucking your surge tank dry. In this situation, you are completely relying on the bypass volume to keep the surge tank full. That isn't bad, as long as you always have more than 50 lb/hr of bypass flow from the aeromotive. If you're running that close to the end of the aeromotive pump, you need to change your pump set up all together.

The real problem is, those are probably the two least consistent fuel pumps in regards to flow (trust me on this, we've flowed a lot of them). either of those pumps could be + or - 20% of the numbers i posted above. So if you have a "good" aeromotive and a "poor" walbro, your discrepancy could be 80, 90, 100+ lb/hr. But you'll never know unless you have them tested (and feel free to get in touch if you do).

In regards to plumbing, Carey is 100% correct: you should have a return line from the surge tank back to the main tank with a 5 psi check valve in it to make sure the surge tank is always pressurized. this raises the boiling point of your gas and sends any air bubbles back to the main tank. in addition, by pressurizing the inlet of the aeromotive, you'll get more flow out of it.

IMHO, you would have been better off just putting two 255's in the tank... way better off with twin 044s... or best off with a sump + weldon.

my .02

 

So if I try to change the walbro, there are any intank pumps that flows better than the walbro 255hp?

Thanks for your help

 

denso pump