I did a small write up when I did my DSM 255 fuel pump into my NA.
Remove the stock unit.
Here is the stock unit compared to the 255(testing to make sure lengths would work.
Remove this screw to remove the stock pump... BTW the screw is a PITA. I started to strip the screw. Had to cut a flat head to get it off and even that was still a PITA.
Here are the two pumps side by side. You will notice there are three differences in the pumps from the outside. First the filter is smaller. Second the filter base is on the opposite side of the pump(will be a small issue later), and third the bottom has different bumps.
The nicest part is that the harness connects perfectly.
The issue with the filter causes a small problem where the stock bottom bracket no longer fits. I cut mine as to mount it.
Well i didn't trust the cut mount and I had seen photos of other Walbro with a metal clamp, I add one to help hold it better. I ran it between the screw mount and the return fuel line. With this clamp the pump doesn't move at all.
The car fired up first try with this. I haven't had a chance to drive my car due to another issues. A local membter just installed one in an NB and his has fired right up. Not sure if he has driven it yet.
Oh.. side notes. You can spin the pump so you don't have to cut the bottom bracket. But it causes the filter to hit something in the tank.
Hopefully this is useful to others. So I did some comparing part numbers for Walbro fuel pumps and it seems like all the evo's and eclipses use the same fuel pump. Which means one should be able to run an evo fuel pump. Why does this matter.
quick comparing of rates.
evo 8 at 14volts 43psi 12.1amps 201.89 Liters/hour
190LPH 14volts 43psi 6.5amps 208.83 Liters/hour
255 HP 14volts 43psi 8 amps 264.4 Liters/hour
more on the DSM and walbro ratings
so if one could find a low mileage evo pump it would be a cheap upgrade.