Topic: Fuel Pump Swap on JDM WRX

[rockcrete]

Well, necessity is the mother of invention.

I discovered today that I was only running around 35PSI fuel pressure and the rail wouldn't hold pressure while cycling the key.

I figured I'd better replace the fuel pump ASAP, so I started hunting. 

The JDM WRX of course has a unique fuel pump, but the Walbro 255LPH units are an easy swap.

Unfortunately, I couldn't find one in town.

What to do?  No stock domestic market WRX or STI ones around, either.

I thought a bunch more and tried a bunch of ideas.

Finally I found a Delphi Twin Turbo Supra one in stock at NAPA (Part # FE0174).  This pump is rated at 42 grams per second confusingly enough, but depending where I look I get a reference of 190LPH or by my own math, I figure that it might actually be 151LPH (I might be wrong).  Anyway, a stock WRX pump is 120LPH and an STI one is 145LPH (nominal ratings).

Now for the installation.

The fuel pump has the right size fittings on it and is the exact same length as stock - looking good.

Trim the supplied rubber hose to the same length as the original piece of hose that connects the pump to the pipes (throw the original away, it's old and soft and mine was actually leaking - also use the supplied screw clamps).

The stock pickup sock conveniently attaches to the bottom of the pump as well (make sure you have it pointing the right way).

Now for the tricky part - the Supra pump is skinnier and doesn't come with a new pump isolator (piece of rubber that mounts the pump at the bottom).

Fortunately, my inelegant solution was easy - I took the old piece of fuel hose I took off the stock pump and inserted it between the side of the pump body and the bracket and then slipped a screw clamp over it and snugged it up.

A quick splice of the supplied wire connector to the original pump pigtail and it all slid back in place.

Started the car up and she now runs great - I even reset the Power FC back to the original maps and it no longer is so prone to detonating under boost!

So, if you're in a pinch, this will work, otherwise track down the Walbro as it's half the price of the Supra unit and flows better!

[Kachow]

Yeah I put the Walbro 255 in my car this winter

[rockcrete]

Hmm, just looked further into the math and I get 42 grams per second as being 204LPH

The Formula is:  (Grams per second) / (Specific weight of gasoline - 0.74) / (millileters per litre - 1000) X (seconds per hour 3600)

42/0.74/1000X3600=204LPH (litres per hour).

Not such a bad fuel pump, then

[RWDragoon]

Supra pumps are one of the best pumps money buys

http://www.mkiv.com/techarticles/fuel_pumps_test_2/index.html  has some tests they performed with this pump

[sniper512]

I am not totally sure what you did with the old hose to make the slimmer pump work? Sorry my brain is fried from the sun today .

[rockcrete]

I just stuck it between the new pump and the bracket when I clamped it so that it wasn't metal touching metal.  I'll probably pull it out again at some point and put something better in there.  I want to put a new sock on the pump too, because I didn't have one when I changed it.......

[sniper512]

Haha okay thanks well I'll have to try throwing my STI pump in this weekend.

[sniper512]

So I put my STi pump in and damn it made a huge difference. I think my pump has been on its way out. The other day the pump stopped and I checked the connector on the top of tank and sure enough the main power wire had burned up. From what I can tell the old pump still worked, but it seems like the impedance may have been really high causing the wire to burnup. The new pump sounds strong and the car has no flat spots anymore. 15psi never felt better:).