enough for pump and race gas.

 

fre- I dont know if you tune yourself, or someone else does it for you but heres a suggestion. If you follow through with this you will need a retune for the added fuel flow. With the walbro feeding the bosch w/an AFPR, you should be able to safely up the base fuel pressure without any problems what so ever. Your probley running a stock base fuel pressure of around 43psi. Im not sure how much boost your running but lets say your running 35psi. Up the base fuel pressure safely to 48psi, if running 32psi/boost up the base fuel pressure to 51psi. On my current car, I run the base fuel pressure as high as I can just before the safety relief valve cracks on the walbro, this is all dependent on the boost level im running. At a 48psi base on your current setup IDC's will drop to 88-90%, for a little added safety and breathing room and obviously more headroom for more boost. Good luck with the car, if you have any questions just shoot me a PM, I dont frequent this site much anymore, not enough tech....too much BS.

 

The inline walboros do not have a relief valve and the primary intank pump almost never sees significant pressures as the second pump is pulling the fuel away as fast as it can supply it. It is always better to have both pumps as close to one another and in the back of the car because pushing through the lines is the hard part.

 

35r and 1000cc with walbro->044 is enough for gasoline, but not e85

 

My base map was done by somebody else, but I have tweaked it since then, so I can make my own changes no problem. I will try the higher base pressure as a way to get more fuel, however, I can't run more boost anyway, because I am spiking out to 33 and dropping to 28 right now (not sure what's up yet) and I only have a 3.5 bar map sensor. The other reason is I am still on the stock block and would like to be able to reuse it upon rebuild this next winter

 

I did a 4ft rise and 1.67gal/min on the .250in lines to get 37psi. When I did .3125 (5an) I got only 13psi loss. 6an is .375in and there was almost zero loss there. We just used slightly different rise #'s. 2 ft is prob closer to reality but I was thinking from a worst case scenario. If stock line is 6an than we are realy good to go because most people are not flowing 1.67gal/min or maxing out 1600cc injectors.

 

in this case, just add another intank walbro.

 

Single bosch 044 or even dual (in series) will not outflow dual walbros plumbed in parallel. I'm hoping that's not what you were suggesting batty in one of your earlier posts.

On my own car I was able to run 10.72@138.08mph with a SINGLE bosch 044 on E85. This was with the stock fuel lines in my 1G AWD. Car weighs 3200lb with me in it. So a bosch 044 can definitely support 650whp on E85 let alone the 044 being fed by a 255. Was running a base fuel pressure of 37psi (stock) with 1600cc/m injectors btw.

 

^^ nice Number ...

 

If you look at 95psi the single 044 flows the same as a dual Wally setup intank parallel. At high pressures a 255 feeding a 044 will def outflow a parallel 255 setup. A dual 044 setup would murder a dual 255 setup in all aspects. At high pressures the 044 rules. At lower pressures the 255's will flow more. We need the most fuel flow however at 75-90psi to begin to be in an area where a single walboro isn't adequate and at that point the 044 is a better candidate in my eyes.

 

It does? At 90psi, a single 044 flows 276lph. A dual 255 setup in parallel at the same pressure level flows 350lph and that's after a big drop. Why are you looking at 95psi anyway? Very few 4G63 folks operate at that fuel line pressure range. That is 55psi boost with a 40psi base pressure. A level most DSM/EVO cars don't operate in. For example I run a base fuel pressure of 37psi. Even if I run 40psi of boost, I'm below 80psi, an area where dual 255's will outperform a single 044. So your statement is not theoretically correct and even if it was, it's not pragmatic since most people don't operate within those parameters.





This is wrong in all practical purposes.


Agreeable.

 

Guys keep in mind that test AMS did was done at 14volts to the pumps. I can almost guarantee 99% of us on this forum is not holding 14V to redline to the fuel pumps SPECIALLY at higher pressures (unless your running a KB BAP). The lower the voltage, the lower the fuel pumps output, and vice versa. The information AMS did provide was very useful though on many scales.

 

Look back at the AMS test graph that was posted. It states that a dual parallel intank Walbro set up flows 250@ 95psi and a Walbro intank and Walbro external in series flows 277@ 95psi. Since a Walbro/Bosch 044 in series wasn't tested it's all speculative at this point, but if a single 044 flows the same as two Walbros in series then one could surmise that the Walbro/ Bosch series combo would surpass this rating by a good margin. Maybe at a ower pressure than 95 too.
I don't think 95 psi is as foreign to an Evo as you may think. I've run 52psi base with smaller injectors than I currently have. Right now I'm at 45psi base. I'm planning on 40psi of boost pressure at which point my base pressure will also have to be increased due to the 1450s I have now are at 95%DC at 34psi.

 

Note:
The twin parallel Walbros in the AMS test were unmodified pumps. Another AMS test shows that a modified Walbro pump flows on par to an 044 until ~80psi.


You darn sure aren't anywhere around 14V if you are using the weak factory wiring. Upgrade the wiring, and you will get ~14V. Retaining the factory wiring and fuel lines guarantees the least possible performance from upgraded pump(s).

 

You are regurgitating flawed logic that I have already addressed by using an extreme example to validate the norm.

1. It's useless to look at line fuel pressure at 95psi and compare the performance of a fuel pump there to another. Why? The VAST MAJORITY of EVO/DSM owners never operate at 95psi line fuel pressure....including you. 34psi(boost) + 45psi(base) = 79psi. You are within the bell curve of most EVO gear heads and duals would outperform the series setup...even for you. That is my point!

2. Fuel pumps flow more at lower pressure so it's redundant to overtax your fuel system by using sky high base fuel pressure to compensate for what is the real problem....undersized injectors.


Like I said, in an optimum fuel line pressure operating range, no series setup will outperform dual parallel walbros. That's why it's the most popular setup for people who need more volume. This is using unmodified intank 255's too. Modified ones or external 392's will perform even much better. There is data to support these assertions.