Scott.T

iTrader: (2)

As with all things (especially on s'net) certain modifications seem to gain sudden popularity with an awful lot of people... do people really understand the benefits and the reasons why they are doing it....

I've been on Scoobynet since 2000 and over the years these have been numerous...
Scoobynet Bacbox's kicked it all off, followed closley be de-cat downpipes, Defi gauges, Eibach's, 17 inch alloys then 18 inch alloys and now 19 inch alloys, TEK ECU's, Knocklinks, ScoobyECU and finally FMIC and Headers......

What seems to be all the rage at the moment are Walbro 255ltr fuel pumps and FSE or SX Regulators........

Someobody namley Walbro and FSE are doing very well out of Scooby Owners at present... but are they really required.

what I hope this thread will answer is :

1. When is a Walbro 255ltr pump required i.e what are the limits of the standard pump (Boost/AFR)
2. Does a Walbro 255ltr pump over power the standard regulator
3. Is a 1992-2000 Pump the same as a 2001-2003 pump
4. Is a pump from a Classic STi any better then a WRX or UK
5. Is a pump from a 01> STi any better then a WRX
6. Is a Prodrive pump a re-badged Walbro
7. Is it more often the case of following the crowd, rather then actually needing one.

Hopefully some of the more technically minded on here will answer the questions (I could answer some, but my main reason for the post is to find answers to No. 1 & No.7).

I do know that on a mates WRX setting the FSE to 3bar or 3.5bar made little difference to his KL activity. But pulling between 1-2 degrees of timing at the point of KL activity sorted it.

Andy.F

Good questions Scott

1. When is a Walbro 255ltr pump required i.e what are the limits of the standard pump (Boost/AFR)
>>>I've yet to find a std pump that cant cope with 320bhp

2. Does a Walbro 255ltr pump over power the standard regulator
>>>Can do on the classic as it runs full pump speed at idle, can be mapped around.

3. Is a 1992-2000 Pump the same as a 2001-2003 pump
>>> No, different model No, not sure about OE flow rates ?

4. Is a pump from a Classic STi any better then a WRX or UK
>>> Not that I'm aware of, more dependant on age/mileage than model.

5. Is a pump from a 01> STi any better then a WRX
>>> My std 03WRX pump copes with 330bhp ok and a JDM Sti9 I mapped was on the edge at 340bhp even on bigger injectors so I guess not a lot of difference ....if any.

6. Is a Prodrive pump a re-badged Walbro
>>> ?

7. Is it more often the case of following the crowd, rather then actually needing one.
>>> for sure !

Sorry I can't answer them all ! Somebody will

Andy

ScoobyDuck

iTrader: (1)

Scott,

Scoobysport & SX not FSE

basicly, what i've summised is that most say the standard pump is OK for anything you can do with stnd turbo / setup, but as you push into the higher bounds of boost (1.25+ ?) the pressure can lag. this is where a new pump helps as its new ! a walbro is cheaper than a subaru pump (IIRC). and it can deliver more, so why not!
then there is questions on the regulator 'holding up' and thats where all this FSE/SX business comes in. some also say the FSE fails / gets worse after some period of use.

I'm sure 90% that change the pump dont require it.

Scott.T

iTrader: (2)

cheers Andy I knew I could count on someone like you....No.1 is higher then I thought and No.5 is interesting.....

No.7 has probably done you out of a bit of business, but then I guess you weren't making much if anything on em' anyway....

P.S Evening Steve, you slipped that one in there quick !!!!

Andy.F

lol, I'm not really into just supplying boxed bits of the shelf Scott, I like to have some technical input to the parts I supply hence hybrid turbos and custom mapping are my main stream work. I normally just advise on the supporting mods required and sometimes supply the hard to find items such as injectors.

cheers

Andy

megrac

I did a test on my factory sti 3 fuel pump and at idle it was returning 1.9L back to the tank. I then changed the pump to an r33 gtr one and got 4.4L going back to the tank.
I would hate to see how much fuel it was (or wasn't) returning when runing full boost.

Butty

iTrader: (2)

No.6 - the Prodrive pump has the tell tale markings ground off the housing and noise absorbing foam sleeve slipped over it. The ground off area is where Walbro stamp up their pumps - but can't tell if it is the 190 or 255 lph version without testing it.

Nick.

JIM THEO

Prodrive's one is a Walbro 255HP, beware though as a Walbro 255 compared with the factory pump gives about 210l/h.
Standard WRX and STI MY 01 > 05 pumps are 130l/h min, measured at 43,5psi (300KPa).
US STI pump is 145l/h.
I'll fit a USDM STI pump to my WRX just for safety (PPP, full decated) as I am going to replace my new age WRX I/C with an STI8 and probably turbo intake hose with an AVO one.
I prefer the USDM STI pump as it's noiseless, factory quality and will not upset my mixtures (IMO) .
JIM

willy

mmm I`m on the sort of edge of wondering if I may benefit from a pump change?
I had Andy F install and map an APexi PFC in Nov last year and had fitted 440s.
Mine is a light green wagon MY95.
I remember Andy saying I still had a small amount of headroom left...
It made 287bhp and 280lb of torque on Prosports RR(dawes set at 1.35, holding 1.15 to redline)... so is there a bit more to come from having a new pump?

*****

jb2000

If you think of it this way your fuel pump is 10 years old, If you want to push the car even more then maybe it would be a good time to replace the fuel pump
Its a bit like buying a 2.5 block and not fitting a new oil pump