I am putting the fuel system together on the Jetta project. I have a small cell with bottom dual -8 outs. single -8 return and a -8 for vent. 2 Walbro 255 in-lines, 2 85micron Earls filters and a 10micron filter.
The way I have it now is the sump exits the cell out the rear, under the car. below the cell I mounted the pumps and 85m filters. Goes cell - filter - pump - Y block - single 8AN up to engine compartment. from here I was just going to send it to the fuel rail, then return from rail to the FPR and back to the cell.
What I have been reading is asymmetrical lines for feed and return can cause some pressure hicups in the rail. Is it better to run a step down for a return post rail and FPR? or just stick with the -8 back to the cell?
Oh, and in general people run a size smaller for return lines… either way, it will be fine. Even if you return line was too small (which it’s not) it wouldn’t cause spikes anywhere but in low fuel requirement situations where the most unused fuel is returned (which it likely wont).
Genuine Walbros are fine, but genuine 044’s are definitely superior (especially in flow). He already had a Walbro, so he just added one. Walbro pumps also have built in check valves whereas 044’s do not.
Lots of fake Walbros and Bosch 044’s out there, though… so who knows who has what and if it was a real one that you read bad things about.
As stated I had a walbro already on the last build, worked peachy keen, so I bought another one. I am not running the pressure through the moon, 50 or so PSI, I think the 830cc injectors at that pressure will feed it plenty. with a single inline and around 3 bar pressure under 26psi on the 3076r I was around 65% dc when I logged it briefly.
I only needed to spend $100 instead of selling my old walbro for like $50 and spending $350+ for 2 044’s. I didnt see the need. Once its up and running, and these fail to work, things can change.
Not to mention the cost of check valves if you want it to fire up on the first key turn or if you are counting on being able to run 1 pump in the event of failure.
Now that I see his injector sizing and base FP guestimates, I see where you are going with this. I would say that you would max those injectors before you even need the other pump…
at a base pressure of 43.5psi yes the pump meets the injectors demands up to around 30psi. its close but at a 50lb base pressure +20-30psi of boost the injectors will outflow the pump. at a 50 lb base pressure the 830cc will need 338lb/hr of fuel. a single bosch can supply that at 100psi(50base +50psi of boost), the new in tanks can supply that at up to about 80-85psi.
ok so say at base I will run 50psi (more than likely less), I would think 20psi boost with that turbo, the crazy aeb head, intake manifold, almost nonexistant exhaust and WAIC providing chilly temps, I would be happy to see 460-500whp. thats a good start to get the car rolling and get some track time in.
