Stiver3

Hi

Im coming up to my 60,000 mile service soon and they recommend changing the fuel pump.

This is something I have considerred myself anyway.

Have been looking at Walbro ones but am open to any offers or recommendations.

Is it best to just stick to original and simply buy a new OE one?

Thanks guys and gals!

BVM

Walbro GSS 341 255lph is a DIRECT bolt in, no cutting or wiring (in a '95 WRX)

Stiver3

Cheers 4 that. I'll look it up. Direct bolt on sounds gd 2 lol.

Danny Boy

iTrader: (2)

Bearing in mind that the Walbro flows alot more fuel than the standard fuel pump so you will be in effect raising your fuel pressure and increasing your fueling.

Dan.

Triple X

iTrader: (1)

Thats why theres a fuel pressure regulator in the end of your fuel rail closest the turbo, so the fueling in effect should remain the same as it was.

Danny Boy

iTrader: (2)

Maybe i have misunderstood this then, but im sure i was told that the Walbro 225Lph pump will overpower the stock reg when it's at idle and off boost conditions, therefore making it run richer at thoses zones in the map.
Fine if it's mapped for it, but will make a change if it's not, could effect the cruise fuel economy.

Dan.

Stiver3

Hum....

Need to look into that a bit more then i guess... the old car is bad enuf on fuel as it is.

Ta.

BVM

We installed the Walbro on a '95 JDM WRX. Then rest the ECM, took it for a 45min drive and the ECM sorted it out. At first the car was pretty rich but it seems to run fine now. Having it remapped at Scooby Clinic this Saturday along with my USDM '02 WRX.
FYI If you have an adj FPR you can lower the line pressure.

AlanPPP

iTrader: (2)

Go on flat4online mate there only £85 inc delivery

Triple X

iTrader: (1)

If it struggles to hold the set pressure at idle/low revs i assume its down to the physical size of the OEM reg not being able to let the increased amount of fuel flow get through it quickly enough back to tank even though the regulator might be fully open?

Danny Boy

iTrader: (2)

Triple X, something like that yes. I have just had my car (MY99 UK Turbo with MD304) remapped by Bob R and he advised me to change the fuel pump to the walbro but not to bother changing the reg from standard.

The standard reg does get a bit overpowered at cruise and idle but it's nothing that can't be mapped around apparently. Once on boost and you are using alot of the fuel that's being pumped round the fuel system it's not so much of a problem.

I would still be of the frame of mind that if a fuel pump needed replacing on a standard car that i would just replace it with another standard one.
If however the car is modified and it's going to be remapped anyway then there is no harm in fitting the uprated pump as any fueling issues can be mapped around.


Dan.

Stiver3

Cheers 4 all ya info.

I reckon i will upgrade as the car has a few mods and hopefully even without a remap she will run fine still till i get the rempa done in the summer.

Adam M

stiver,

speak to mark at lateral performance, think he can match these fuel pump prices, but he will explain the thing to do with the fuel pressure regulator. I think he sells those too but isn't your pushy salesman type so will sell you what you want/need and nothing more.

020 8420 5444

Stiver3

Thanks for that. Yeh ive heard that the fuel pressure regulator may need something doing to it.

I will try them sometime this week.

Cheers Adam

Tone Loc

iTrader: (1)

Not sure i understand that.... the OEM ecu and many aftermarket ones will be using closed loop fueling on idle and cruise so will adjust the injector opening times to reach 14.7:1 AFR. No need to be 'mapped around' .

I've had a Walbro and OEM reg for nearly two years now and not notice the reg being overpowered at all..... but as with everything Subaru this doesn't mean it will be the same for everybody.

Tony.

chris singleton

Just ordered mine from Lateral Performance

Danny Boy

iTrader: (2)

Hi Tony

Maybe i misunderstood what Bob said, as always i stand to be corrected if im wrong, still learning every day just like everyone else

It would make sense what you say about the closed loop fueling but maybe i has a limit to how much i can compensate for.

I seem to remember reading somewhere that the standard pump was only rated at 90/110Lph (maybe someone can correct me here too ) which if that is the case then an upgrade to a 255Lph pump is one hell of a jump in fuel flow so i would be surprised if it did not have some consequences attached to it.

Dan.

StickyMicky

do what i am going to do and fit a sti8 pump thats done next to no miles, and been removed for sumbody to fit a walbro one

brunny42

a walbro 255 litre an hour fuel pump is rated up to 550 bhp, if your car is not running 550 bhp there is an issue with oe fuel reg not being able to return the excess fuel, which will cause your fuelling to go out, i agree you may be running a few mods so yes its wise to upgrade the pump, i believe graham goode does a 216 litre an hour pump at 4 bar of pressure,this may be more suited for you.

http://www.grahamgoode.com/subaru/pa...8&item=GGS1187

also if thinking of fitting an adjustable fuel reg, i heard the fse are not too clever and dont maintain pressure, and the sx type are much superior and not heard of any failures,imho

BVM

Ditto what Tone Loc said.

I have had a Walbro 255LPH in my WRX and Skyline for over a year now. The Skyline did need an AFPR but the scooby is doing just fine with the stock FPR.

JIM THEO

This flows much more than the Walbro 255l/h mate!
JIM

Jay m A

iTrader: (2)

For reasons mentioned on this thread I've got the walbro 190 lph pump.

If there are issues with the 255 overpowering the reg, be it OE or FSE or whatever, why get it if you are not going over 450BHP, when the 190 will do it fine.

brunny42

jim theo, not wanting to argue but not too sure on the 255 l/h is this rated at 3 bar fuel rate, if so a pump rated at 255l/h at 3 bar will deliver more fuel than a pump rated at 216 l/h at 4 bar, devide 216 by 4 bar then multiply by 3 this equals 162l/h at 3 bar which the reg in rail will set the pump to, so that is less than 255 l/h at 3 bar, but like i said not sure on the walbro 255l/h dont know what figure pressure this rate is set to

JIM THEO

This is a typical Walbro 255l/h flow chart:



You can see at 43,5 psi it flows about 56 US gallons = 210l/h
JIM

brunny42

ah so the 255l/h does not actually stand for 255 litres an hour, it is a pump part number or refference,the pump only delivers 210 litres an hour of fuel as you say, but like i converted 216 litres of fuel at 4 bar to get 162 litres of fuel at 3 bar, which like i said is less than what you say 210 litres of fuel in one hour.
you trying to say 210 is less than 162, i think its getting too late

R19KET

Sorry, but you can't work out flow, or compare pumps like that.

For a start, pumps flow "more" at lower pressure.

The only way to compare, is to check the flow maps.

Mark

brunny42

ah right now it is too late, well at least for me i stand corrected,and man enough to admit it, i only said it "may be " more suited and worth while checking
well god damn you learn every day, thank you for your inputs and corrections, thats what these places are for well done thanks

JIM THEO

As Mark said you claculate flow from flow maps only.
The effective area for our cars is between 43,5 psi and 43,5 psi + turbo boost which is more or less between 43-60 psi.
If you see in the above graph which is directly from horses mouth at 60 psi the Walbro 255HP flows 50 US gallons per hour which is much lower than 255l/h!
JIM

R19KET

Jim,

It's more realistic to use the graph for 13.5v, which is about the right working voltage. Using the graph you've posted, I'd estimate 67.5 US gallons, or about 53.6UK gallons, 243lts, close enough to 255lt given my rough calc's.

Brunny,

The 255lt is a flow rating, and IIRC, it's taken at 3bar (43.5psi). If you look at the graph, if you only wanted to run 10psi, it would flow circa 84 US gallons, 67 UK gallons, or 305lts !

Mark.

brunny42

yes i have spotted my error, sorry like i said dont want to argue but discuss, so thats what we did, and i bet there was more people than just myself that learnt something new, cheers,but from a description of 255lph any one would think this actually meant 255 litres,