Bob originally mentioned this, and on checking my fuel pressure it was about 3 bar at idle, atmospheric, throttle blipped etc. Fitting a new regulator has given the expected response, although perhaps not quite the setting minus idle vac it is not far off.

The closed loop correction varied over time and sometimes it started abruptly. Leaning out the map sorted it for a while and then it happened again, as though fuel pressure was rising over time.

Any others? Should we all be doing a regulator with the fuel pump because of this issue?

 

John

On my 01 I am running the standard regulator with the uprated pump and its fine.

 

I ran mine on a stock set up (MY98) for over 10k miles without any issues

 

I was looking at getting an up-rated Walbro fuel pump but had heard that they don't make any difference at all.

Any comments from you guys ???

 

The pump can make a huge difference - especially if you have upped your boost.

On track I had a real problem controlling the egts at the top end - and no amount of mapping would correct it - simply it was the fuel pump not providing enough fuel. With the Walbro - problem solved - plenty of headroom in fuel flow and egts were fine.

So IMHO a HUGE difference for one low cost change.

Rannoch

 

Indeed agree massive benefits from the pump when you tune UK cars much beyond the high 200s and it seems STis at all. Just wondering about the idle fuel pressure thing. Needed to change the regulator anyway because it was in the way of the turbo. I suppose it only became an issue after the 550s.

 

It is overpowering my regulator on the 22B like you say. It is having the new Mark Aigin supplied reg fitted Thursday then another re-map The figure with the "hose off" was too high i.e its not closing properly (as I understand it?)

 

The std fuel reg has about a 2.0mm orifice to flow all the fuel thro' so its no suprise it gets backed up when the Walbro pump is installed, also means it ends up very non linear and variable. RCM are now offering the SX reg plus fitting kit as a complete package and will also install to boot, its a pig of a job on the Classic cars but the new age have the reg at the front of the fuel rail. Be aware that the rail adaptor that fits the classics will not fit a new age.

 

Andy, no didn't monitor the fuel pressure, didn't have the means to do so, all that I can remember were that my IDC's dropped after fitting and a remap.

Can't remember much about the car at all these days, it's been in pieces since September

 

I fitted an Walbro pump and fuel pressure regulator recently and the car runs a lot better. Pick up seems much improved.

 

Is it recommended to fit an uprated fuel pump/regulator prior to a remap. Could the car run too rich or does the duty cycle of the injectors simply lower to supply less fuel? Going to be fitting Link set up in the not too distant future.

 

John if your still using the standard fpr I guess you havn't converted the fuel rails into a parallel configuration. So you don't believe thats necessary? (I'm only asking, not sayoing your wrong)

Duncan

 

Triple X - I would recommened that you uprate both before the remap IMHO.

Definatley the pump if not both.

 

Bob,

Being a bit thick here, who are RCM?

Price?

F
ps I'd ask'em if I knew who they were.

 

Here we go again

Question: Are any of the mappers / tuners of STI-7's changing the regulators....if so why ? if not why ?

Once again, why would Prodrive supply uprated pumps with the new PPP but not regulators if neccessary ?

Seems like a whole new tin of worms about to be unleashed but I need to know as I am having a remapp and new fuel pump stuck on me old JDM STI7.

Cheers,
Ray

PS: What is the worst that can happen if the regulator is not replaced.....is it the same as not upgrading the fuel pump...ie: fuel starvation and bang ! ??

 

RCM - Roger Clark Motorsport

 

Had 2 standard ones go. Wanted to replace 1st one with uprated but was over xmas and had mapping booked but couldn't. Sure enough that didn't last either.

 

bttt

 

bttt

 

This might be a dumb question but how do you measure the fuel pressure if you dont have an in car gauge to display it?

 

You use a gauge under the bonnet, or get a dash one.

 

I knew it was a dumb question!

 

Wether to change a reg or not in addition to the pump is really down to what level you are going to upgrade, the further you go the more specific you need to be with fueling, as a guide, if installing uprated injectors then the reg "should" be changed, if sticking with std's then probably ok as is. This is because granularity ids affected when injectors are changed and a small pressure variation can cuase a much bigger fueling change as a result.

bob

 

Bob, im going to be arranging for a Link setup i bought to mapped by yourself (used to be Toby Meech's). Is it ok to use NGK PFR-7B's when doing so? Also going to fit an uprated fuel pump to go with the Link, so i would be ok leaving the standard FPR?

 

My Walbro/OE FPR/440's have never given a problem. They're currently run at 98%......

Aftermarket FPR goes on with the 550's though.

Richard

 

Triple X, answer to all is yes, 7B's are spot on, if the reg is a problem then I will soon see it and can advise acccordingly,

cheers

bob

 

Thanks Bob.

 

John

What model of Walbro fit in a Impreza MY99 ?

GSS341 o GSS342 ?

 

GSS341

 

And an STi 7/8?

Bob (or anyone else ), you say when fitting bigger IJ's the FPR becomes more important? Bigger than what? I ask because the STi 7/8 has 565cc's (right?) so would they constitute "bigger" than say what I assume is being called "standard" (440's?) so basically, on a 7/8, do you think an uprated FPR is required if you uprate the pump?

Ta,

Matt