Greetings, so i did a search on this and i havent found anything super concrete, regarding this issue. What id like to know is if anyone with a setup using larger injectors and a higher flowing intank fuel pump, are experiencing fuel starvation when their gas tank is down to a third fuel, as indicated by the gauge? I never noticed this problem on my first evo, running a fully oem fuel system. But, now that i run id 1000's and a walbro 450, i find that im getting fuel starvation at a third full tank. Under acceleration, its fine. But, upon coming to a stop, my afrs start to fluctuate wildly, almost to the point where the engine stalls from going lean. They will fluctuate dramatically at first, but as the fuel settles down, they smooth out. As soon as i fill the tank back up with gas, the problem is gone. I realize the evo uses a saddle style gas tank, and that is probably the basis behind the problem, but im wondering if there is any fix? Would moving the fuel return to the passenger side of the tank help? Could running a larger transfer vacuum hose do anything? Currently im using a standard strainer sock on the pump, with a adapter to mount the pump in the stock hanger. I have a screen style inline fuel filter about 8" before the fuel rail, on the feed line, and other than the injectors, the rail, pressure regulator and return is stock. Do i just need to bite the bullet and run some type of surge tank? Any input or similar experience story would be appreciated greatly. Thanks for reading this!
-WILL

 

I've only heard of this being a problem on a track or somewhere while taking long turns. There are some different options of surge tanks for that.

https://www.maperformance.com/produc...tsubishi-evo-x

But you mean just in a straight line? I've never heard of that.

 

You might also have an issue with the pickup on your Walbro. Are you using the stock housing or an aftermarket hanger?
Most everyone that does track duty ends up with a surge tank as there's aren't any great solutions for the cornering issue. I've seen a couple people try something like the Holly Hyrdramat without much luck.

 

splattj, ive got the oem hanger, with a billet adapter ring that centers the pump inside the hanger. Ive got stock fuel lines with a jegs screen type filter, just prior to the rail on the feed side. The regulator is stock, and its got injector dynamics, 1000cc model injectors. The problem only occurs at like 1/3 full, during normal, full stop braking. The afrs will immediately go lean, then recover, in a cycle lasting approx. 10 seconds, at which time it will recover and idle at 14.7. It doesnt occur at all during take off or cornering. Once i fill it back up, the problem goes away. Ive been thinking about something i read awhile back, about the evo x having some type of vacuum system running to the tank, for the purpose of feeding fuel from the passenger side of the tank, to the pump side. I may be completely off with that, or maybe i mis-read. Anyone know if thats true? And if it is, how exactly does it work? Id really like to avoid spending thousands of dollars on a intank surge or an external type.