deanoM

I’ve just fitted a uprated fuel pump and an uprated rising rate reg.
My question is as its adjustable, what pressure should the reg setup to be? Ideally it needs to be on a rolling road, but am I looking at 40psi, or lower?


It’s running 1.2 bar max, before it ran Ok, it now hesitates mildly, and does not seem to reach full boost.
Is this over fuelling or under fuelling?


Any help appreciated, I live in Cambs and need a decent rolling road who will not overcharge me, are there any in this area.

Cheers

Dean

sparkster

I have a 93wrx running uprated fuel pump and regulator with gauge, fully decatted+induction kit.

I typically run about 1.1bar depending on weather conditions.

It was set up quite low at 2.25bar. If you add the boost pressure to that of 1.1 that gives a total of only 3.35bar. Ive been reading that you should be set up to run 4 bar of fuel pressure on full boost.

For example, 4bar minus the 1.1bar boost is equal to 2.9bar. Therefore i should have my regulator set up to run 2.9bar at idle.

However, you can get different readings at idle. When i start up i run 3 bar. Having run the car for a while the idle fuel pressure drops to around 2.75bar. To be honest, i'm not sure what condition your engine should be in when setting up (operating temp or just started up).

The rise from 2.25 bar to what i have now has meant that the car runs a lot smoother

sparkster

p.s., i'm not an expert but i think i'm along the right lines. Get a second opinion

deanoM

I've been told as the car has been re-mapped already, it's best to run the std reg but keep the uprated pump.
As it's an older car now (93wrx), is it best not to run over 1.15 bar boost? But have the fuelling checked on the rolling rd for any problems, car has had downpipe, filter, exhaust, and a re-map, plus I use Optimax.

sparkster

To be honest, i havent changed the boost on my 93WRX (yes it is running a little high but that could be a gauge problem) As soon as i have got the cooling side of things sorted out ie better intercooler and maybe water injection then i'll be putting the boost up. I certainly wouldnt think of putting the boost up on a 93WRX jap import without other modifications. If i was, the Knocklink would be sitting on the windscreen showing me "when" the engine was going to blow.

I dont see why the boost cant be turned up on a 93WRX without the necessary precautions

Pavlo

you should set the pressure at idle with the vac hose to the reg disconnected and blocked (to keep idle steady).

You will then see the relative pressure at atmospheric. Normally this is 3bar or 43.5psi, and maintained relative to manifold thoughout the boost range (which is why it appears lower at idle).

So once you set the pressure at idle, and reconnect the vac hose you should see it drop again. Although the RR regs drop more at idle as well as rising more on boost.

paul

deanoM

Ok we set it at 3 bar, with the vac hose blocked.
Since the RR rate reg, at high revs it seems to be holding back.
I'm going to go back to the original reg to see if my problems clear up.
The uprated fuel pump should not cause any problems?

ta

[Edited by deanoM - 5/27/2003 2:45:19 PM]

Pavlo

Also bear in mind that it is a rising rate fuel reg. So you will get more fuel at higher boost than a standard fuel reg.

Uprated fuel pump shouldn't cause an issue, in fact the new fuel reg should make things a bit better as the standard ones tend to get overpowered by the pump at low fuel flow (ie low rpm and boost).

Get an AFR meter of some sort on there too, that is covered widely on scoobynet.

Paul

deanoM

The problem I have is still at high revs the car holds back, is my map causing problems?

Or shall I revert to std reg to see if it clears things up, I then know the rr reg needs setting up again.