DSM Walbro 255 install/write-up

[wildfire0310]

I did a small write up when I did my DSM 255 fuel pump into my NA.

Remove the stock unit.

http://img.photobucket.com/albums/v132/lostDSMsoul/miata/fuel%20pump/stockunit.jpg


Here is the stock unit compared to the 255(testing to make sure lengths would work.

http://img.photobucket.com/albums/v132/lostDSMsoul/miata/fuel%20pump/stockunitwith255.jpg


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.

http://img.photobucket.com/albums/v132/lostDSMsoul/miata/fuel%20pump/*****_screw.jpg


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.

http://img.photobucket.com/albums/v132/lostDSMsoul/miata/fuel%20pump/twopumps.jpg


The nicest part is that the harness connects perfectly.

http://img.photobucket.com/albums/v132/lostDSMsoul/miata/fuel%20pump/harness.jpg

The issue with the filter causes a small problem where the stock bottom bracket no longer fits. I cut mine as to mount it.

http://img.photobucket.com/albums/v132/lostDSMsoul/miata/fuel%20pump/cutbottom.jpg


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.

http://img.photobucket.com/albums/v132/lostDSMsoul/miata/fuel%20pump/newmount.jpg


The car fired up first try with this. I haven't had a chance to drive my car due to another issues. Mod_Scott just installed one in an NB and his has fired right up. Not sure if he has driving 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
http://www.roadraceengineering.com/fuelpumpflowrates.htm

so if one could find a low mileage evo pump it would be a cheap upgrade.

[Jack-MX5ATLanta.com]

Cool deal, nice write up mate!

[MoD_Scotty]

Mine was REALLY easy to install. I just cut about 1/2" off the metal pipe that connects to the output of the pump. Otherwise, I spliced the walbro harness to the Miata end. I would have solder/heatshrunk it, but of course I couldn't find the two bags of heat shrink I bought a few months ago. Here's what mine looked like:

http://i70.photobucket.com/albums/i95/avatargsr/99Miata/FPandRoolbar/P1010165.jpg

[wildfire0310]

Mine was REALLY easy to install. I just cut about 1/2" off the metal pipe that connects to the output of the pump. Otherwise, I spliced the walbro harness to the Miata end. I would have solder/heatshrunk it, but of course I couldn't find the two bags of heat shrink I bought a few months ago. Here's what mine looked like:

http://i70.photobucket.com/albums/i95/avatargsr/99Miata/FPandRoolbar/P1010165.jpg

See I didn't have to cut my pipe or even split off the harness it all bolted up the same. It should have been same for you as the part number for the NB walbro was the same as the NA. Mmm weird.

[darknessprevails]

this thread helped a ton i am about to finish my install up and i have been debateing back and forth about differnt ideas looks like i ll just be cutting that bell peice off and clamping a hose on there : ( hate to do it but oh well modfi 90 model

[MoD_Scotty]

See I didn't have to cut my pipe or even split off the harness it all bolted up the same. It should have been same for you as the part number for the NB walbro was the same as the NA. Mmm weird.

Mine also might not have technically been for a DSM...I got it from a guy on a Mirage/Colt/Summit forum, so it might be a little different.

But I did notice that the way I installed mine, I didn't have to modify the bottom part (which you cut up). This way it sat pretty nicely, and the filter seemed like it would stay on no problem.

Also, just as an update, I've been driving the car every day since the install, and I've had 0 problems. It's been getting identical MPG as well.