StatesideRS

I have a version 1 STi RA (EJ20G) using the stock fuel pump. Does anybody know what the pound/hour capacity of the stock EJ20G pumps are? Is there a difference between pumps used in the RA and other variants?

The reason for my question, I'm going to be upgrading to 550cc injectors when I get tuned and am deciding which fuel pump to go with...

a) stock STi RA
b) stock 2.5 USDM STi (edit: found out these are 145 lph)
c) Walbro 255

I've heard the Walbro is just plain overkill for a nearly stock EJ20G and results in crappy gas mileage and pig rich idle. If I can safely use my stock pump or STi, that's what I'll go with.

Cheers,
Derek

bpm1588

i have the same car as yourself and am planning doing a few mods.i have been advised to fit a walbro 255 and an adjustable fuel pressure regulator.i guess the regulator can be set to make sure its not to rich but up shot you know its not going to run lean either.

StatesideRS

That is the other option - Walbro 255 with an adjustable FPR. I was advised by my tuner to stay with the stock regulator, but I agree a 255 will over run the stock regulator.

What fuel pressure regulator do you intend to run?

bpm1588

have'nt bought one yet,there's so many but the SX one seems to be fairly well respected,is a bit costly compared to others though.don't know if your a member yet over on type-ra.co.uk but if not sign up,its a very good resource of info.........i will say be carefull with fuel octane in your ver 1 sti ra and mods.the standard ecu "SB" runs very lean in stock form.

StatesideRS

I'm in the US, so highest I get is 93 on pump (RON+MON)/2 formula.

I really don't drive the car hard (never sees above 5k rpm or much above 10psi) for the very reason that it needs a tune. I have a wideband installed, and it really does run very lean for a stock motor (11.5-12:1 under higher boost load).

I have a Power FC but have not installed it yet or had it tuned. I'm waiting to install 550cc injectors before I head off to a tuner.

I'm already a member on type-ra.co.uk, definately a great resource. I've posted up my question over there as well.

bpm1588

it will be a good idea having your power fc fitted and mapped to suit the fuel etc....up to now i have just been buying bits and pieces for the car,nothing fitted as yet.i plan to have all mods fitted and the car mapped together.the only thing i did fit was a 2nd hand 4 plug ecu and chip from polar performance to make sure it was going to run ok on our 97 ron fuel.

the guy scott who runs polar performance recons hes only seen a couple of ver 1 sti ra's and hes been mapping and chipping pre 1996 subarus for a few years now,he's done hundreds.as he says the sb ecu runs very high boost duty and a very lean map,stock.im guessing they are so rare because most have blown up and never made it too the export ship.

StatesideRS

I always like posting over here because there are no reliable sources on the JDM market cars on any of the US forums.

Since the day my swap was finished, I have been getting a fuel cut, specifically at 15/16 psi and also at other spots in the rev band. I don't know if this is the result of knock or some other problem the ecu is detecting. I have never seen a CEL for the 14 months I've had the motor running. It runs smooth as the day I started it but DEFINATELY needs to be tuned. One step colder spark plugs and a FMIC help keep the combustion temps down, but it really can't compensate for the lower octane fuel.

Apparently this is a common problem for the EJ20G motor, I've seen this topic come up a lot on the NASIOC board from members with motor swaps.

Thanks a lot for the replies. Getting information about JDM motors in the states is like pulling teeth.... nobody has any idea about them.

How do you find the chipped ECU? I'm considering running that over the Power FC for reliablity reasons. Do you have any idea on the costs?

Sc0oby

had been running the standard sti pump on my97 v3 model tune to 240hp at the wheels and pump is not leaning out

bpm1588

your car is boosting more than standard,stock is a shade over 13 psi.sounds like your car is hitting the stock ecu fuel cut of point.

im very happy with the chipped ecu from polar performance but like i said before its really just a stop gap for safety till i get all my mods fitted.then i will be going for something like a esl mapable board or depending on turbo choice maybe a maf less ecu like simtech.

drop scott a line,he's a top guy,very helpfull and knows a lot more than most about these cars.he may have a solution for you.
scott.t@polarperformance.co.uk
PolarPerformance

bpm1588

upgrading the fuel pump is just a easy safety thing,like you say its something you may never need running at that kind of power level.

StatesideRS

My motor is definately running more boost then it's supposed to. I can hit 16 psi before I get fuel cut. Part of this is due to the 3" bellmouth downpipe I've fitted, there may be a problem with the boost control solenoid as well.

My goal with the 550cc injectors and a tune is ~260-270 whp, I think that is out of the comfort zone for the stock 2.0 liter pump.

I'll get in touch with Scott, it sounds like he has a wealth of knowledge for the classic scoobies.