Frazer

Hi,

I had my car mapped by AndyF yesterday and he noticed that my 800cc injectors were maxing out at 600 cc (could only run my MD321T to 1.6 bar) I checked with the person who sold me the injectors and they were flow tested at 800cc.

Andy said it could possibly be a problem some where else in the fuel system, i've got a Walbro fuel pump (do these sometimes fail?) apart from that everything else is standard. Is there a way to check if anything is wrong in the fuel system? Also what pressure should it be running standard?

thanks in advance

Stevesbluewrx

iTrader: (4)

Standard fuel pressure is 3.0bar I think?

What year is your car? My bugeye with same turbo,550cc (PINK) injectors ,255 walbro pump and FPR was set at 3.2bar.

It peaked at 1.7bar and kepts pretty good down to 1.6bar and 1.55bar.

One thing I did do prior to the map to get the best out of it was change the fuel filter too to be on the safe side.

Steve

Frazer

Hi Steve,

Its a JDM STi Bug eye. Did a fuel filter change before the map, it's defo not the injectors though they were flow matched about a month ago to 800cc, maybe the walbro has gone bad.

Stevesbluewrx

iTrader: (4)

Hey matey,

I don't have the answer buddy. AFP is well known mate for his skills.

It could be the FP but this doesn't make sense. Maybe a FPR is required?

Steve

Turbotits

iTrader: (2)

yThe pumps do fail yes. I had mine mapped many moons ago and after about a year noticed i was getting some knock activity> took it back to the mapper and it was the pump found not to be supplying enough pressure at middle/high revs. a pump replacement solved it

Frazer

Don't think I need a adjustable fuel pressure regulator, Andy just runs bigger injectors no AFPR on his 500 HP Spec C.

Jolly Green Monster

iTrader: (4)

you need to borrow a fuel pressure gauge and monitor pressure on boost.. it should go to 3bar plus boost pressure roughly and hold all the time on boost.. I suspect it will drop off at high rpm.. could be either the fuel pump or the fuel pressure reg

Simon

dunx

iTrader: (3)

Your fpr could be failing.... see above !

dunx

banny sti

iTrader: (68)

If you have modified injectors then you will need an AFPR to increase the fuel pressure for them to flow the 800cc. At 3bar they probably do flow 600cc and at 4bar 800cc.

Banny

Frazer

Banny,

I was under the impression i wouldn't need a AFPR for my 800cc's to run 800. Andy didn't mention that when he was telling me what could be up with the fueling. Anyone else have any thoughts on this?

Cheers in advance
N

Frazer

Does anyone know for sure if i have to run a adjustable FPR to make my 800's run at 800?

Cheers
N

LegacySTi

iTrader: (13)

You said 800cc were flow matched to this...

So assuming not original 800cc ?

So as above maybe need FPR to flow to injectors limit.

Frazer

Hi,

Yeah they are oem Subaru injectors flow matched to 800cc

banny sti

iTrader: (68)

Then you will defo need an fpr to make them flow 800c, as the standard subaru injectors have to be modified to flow 800cc

Banny

Butty

iTrader: (2)

Caps removed?
Was there a sheet from the flow tester to state what pressure was used to get 800cc/min?

Jolly Green Monster

iTrader: (4)

I don't totally agree.. you would see more cc from them with adjustable reg but the flow tests are normally done at 3bar (ie. standard pressure).

Have you put a fuel pressure gauge on and checked the pressure? you will probably find the fuel pressure is dropping off?

If it isn't then fitting an adjustable FPR would give you more headroom yes but I see no issue running larger injectors on the standard FPR.. higher pressure can help atomisation and they will obviously flow more but you still should get close to 800cc on the standard FPR imho

Simon

Stevesbluewrx

iTrader: (4)

Smart ****

Reminds me dear boy. Going to see Mark next week about the flow tested injectors. Then another session with me and the mask.

Steve

bluenose172

iTrader: (2)

I wasn't there when Neil(my brother) got Andy to map the car, but apparently setting the injectors at 800cc caused audible knock at idle, so it wasn't like it was leaning out as load/revs rose. I think it's his fuel pressure that's the problem.