hi guys just fitted my walbro fuel pump to my 94 sti.what i wanted to kno is will it change the fuel comsumpition of the car? if it has a faster flow rate or will it basically be the same.prob a simple answer to this .lol cheers guys

 

AFAIK it shouldn't because the flow will still be controlled by the standard fuel regulator, (my fuel consumption plummeted after having a Walbro fitted, although that was because of the remap and heavier right foot )

Anyone confirm?

 

lol ok mate cheers

 

The regulator controls the fuelling, not the pump.

 

The above is true. And in theory there should be no difference, but in my experience there will be a difference, less MPG.

I've recently fitted a walbro to my 1996 STi Ra and it reduced the MPG by about 2 or 3. The reason for this is that the standard fuel pressure regulator is not able to maintain the standard fuel pressure. The fix is to fit an aftermarket FPR.

It's not too bad when lightly loaded at cruise because the closed loop lambda will correct the fueling back down. But this is not the case when on boost etc.

 

Yes that's a good point -an uprated fuel pump CAN cause a regulator that's already on its last legs to start to fail, meaning less (or no!) control over fuel pressure and hence higher fuel consumption. A healthy regulator should be OK, but they can go, meaning a replacement for a fancy one is needed, which will then add fuel pressure adjustability, handy if you're planning a big power remap. For example, my injectors have been flow tested at 500cc at 3 bar fuel pressure, 550cc at 3.5 bar and 600cc at 4 bar, IIRC. Which is handy if I ever go to a bigger turbo than my current VF35.

 

iv'e just fitted one to my 06 sti"waiting for my remap"and i do find the car a bit more thirsty plus i think its a bit slugish as well.maby overfueling?but im sure once its remaped it'll go like stink.......anyway in my case the cars harder on fuel

 

You don't get something for nothing. You want more power then expect your consumption to go down.

Got a few toys under the bonnet on my wagon. The fuel consumption is cr@p. However smiles per miles

 

lol ok cheers guys i did notice a difference but thought it was just me.anybody recomend what fuel preasure regular to use.what about an fse? cheers guys

 

I bought an adjustable one with a gauge of flee bay, basically the same as an SX regulator but for under half the price and it works very well.

 

Just dragging this one back!!

One thing i've always wondered but never asked, surely if the fuel pump did overide the standard FPR wouldn't the ECU reduce IDC when running in closed loop mode to get back to target O2? meaning cruising mpg would be unchanged?

Also would the walbro only overpower the standard FPR at low loads due to minimal engine fuel requirements?