Adjustable FPR's for EF 6

[Hotwire]

Hey all,

A long time ago, I had my car dyno’d, and as you can see by the dyno printouts (see below), it was running rich as (top readout, bottom two AFR lines). It was at a dyno day at BDT, and they then went demonstrating the effects of reducing the fuel pressure to increase Air Fuel ratios, increasing performance and also improving the economy. The final result was a 3kW gain and with the AFR sitting around 12.1-12.8 as seen on the lower picture.

Now whenever I have contacted them lately, they just try and sell me a UniChip is they are now a retailer, and don’t want to know about the AFPR method. SO, I want to install one myself, and then have it adjusted on a dyno (BDT or Elsewhere) to improve economy and performance.

I am aware that standard fuel rail runs at 270kpa or 39.15psi. I have been looking at other inline adjustable FPR’s on Ebay, and came across the following:
http://cgi.ebay.com.au/ws/eBayISAPI.dll?ViewItem&category=32624&item=4541843724&rd=1
I believe this to be correct for my usage, as it is adjustable from 20-85psi, and also has a vaccum feed, which would be fed from the manifold to adjust pressure accordingly at idle and WOT. Accordingly, I would set the fuel rail pressure again at 39 psi to ensure no running lean until I could get it onto a Dyno to set correct AFR’s

NOW, can anyone confirm that I am correct, as I don’t want to go spending $150 on buying and fitting this thing to find out it doesn’t work. Also, could anyone recommend a dyno shop in Adelaide that would tune it for me?? (Grant or Martin??)

Thanks
Lee

Dyno Results

**Edit** If pic doesnt show, its in my gallery

[prydey]

try rpm on deloraine ave. i had the exact same thing. obviously all fords will. runs rich as buggery at top end. they too suggested adjustable fuel pressure but from memory they quoted around $190 fitted and tuned. with fuel the way it is i might start down this road again also. let me know how you go if you do it.

[EDXR8]

The first problem with all these adjustable regs is that they are installed in the fuel return line and don't replace the stock reg. This is fine if you want to increase fuel pressure, but if you try to drop it the stock reg will take over and hold it at 39psi. For it to work you will have to remove the stock reg somehow. Another problem is the lower fuel pressure will result in the EEC gradually learning (over a few hundred kms) to richen up the mix to get the correct AF ratio under light load and this will then transfer back to WOT, so the result may not last.

Personally I would be putting the money towards a EEC mods like a unichip or chiptorque. If you are running a stock or mild cam, an off the shelf chiptorque chip can be quite usefull because it is simply changing the AF ratio targets in the fuel table and usually add some timing too. With large cams it becomes more difficult as the load functions are thrown out quite a bit.

[Hotwire]

[4.9 EF Futura]

[EDXR8]

It doesn't take long at all to apply the changes to the WOT maps, it actually occurs straight away. As soon as you start the car it will target the AF ratio given inthe fuel maps, for cruising that is 14.7. The EEC knows how much fuel it should give to make that AF ratio but obviously that is not always correct, especially when mods are done or fp is changes. To adapt it has a function called KAM or short term fuel memory, so yeah as you said it then measures how much more fuel is required to obtain the correct AF ratio and then it applies that across the board.

The thing is that lowering the fp will have a greater effect at WOT than while cruising so although the EEC will add more fuel to compensate for the lower fp, it won't be able to totally adapt at WOT. So it will work to some degree, but to get the desired AF ratio at WOT you will probably need to dramatically reduce the fp, and that may max out the injectors.

Regarding the chip, yeah I understand that you want a cheap fix and I think the reg may be worth a try. What I was thinking of was the off the shelf chiptorque chips for $595, still expensive but at least they are cheaper than the unichips at $1200.

[unclewoja]

Well then the answer is easy isn't it?

Increase the fuel pressure. This reduces injector duty cycle and pulse width @ cruise, so it will lower fuel across the map. Dat's what we want isn't it?

You could just wait till a few of us here get the Megasquirt-II adapted to the Falcons and get complete control.

Edit: Jesus! Unichips $1200? I'll gladly sell Megasquirts with wideband O2 for $1200. That's just stupid to spend that much on a unichip.

[Hotwire]

if the EEC looks for an optimum of 14.7, looking at my dyno readout it gets no where even near that. (12.5 is best at low revs/power) Now, I know that is at WOT, but just cruising, does the AFR change that much? Surely just under normal cruising the AFR would be close to 13.5?? so there is improvement to be made I would have thought. What would be everyones thoughts on this?

[Waggin]

[Hotwire]

Waggin,

could you explain a little more to me? so when at WOT its in open loop mode (ie. does not look to 02 sensor reading) but when at cruising it is in closed loop. What sort of AFR are normal during closed loop operation? Does it often range over the 14.7 and therefore increasing of fuel is common?

My car is running rich and I seem luck to get 400kms out of 58L of fuel (14.5L/100kms) which is pretty average.

[4.9 EF Futura]

[uglybob]

are those gauges worth it martin? mine is running very rich, and have been following this thread with interest as i was going to be throwing an AFPR onto my car

[4.9 EF Futura]

[uglybob]

whats the cost like for them mart? i'm pretty uninformed about the EEC etc, so i guess it would do sweet FA for me really!

[4.9 EF Futura]

Think it set me back about $150

[Hotwire]

So really, an adjustable FPR "should" only help at WOT performance. So my s**t fuel economy is most likely to be occuring due to dodgy O2 sensor or MAP sensor then? I ran the self diagnostics on my car and MAP seemed to come up ok, does anyone then know how to check the O2 sensor for correct operation?

[USELESS]

If the ego is the eyes of the ecu to adjust fuel then why not get an adjustable fuel pressure regulator and disconnect the ego.Sure the car will go to rich but that can be adjusted with the pressure regulator...cant it?

[Greenmachine]

I saw a Malpassi adjustable regulator on ebay a while ago that had no guage on it but looked very much to have the right shape and bracket to be a straight bolt on to the EF fuel rail exactly as per the factory reg - ie. it had an O ringed spiggot out the side and a bracket that had 2 holes in line with and either side of that spiggot - and there was a hose fitting sticking out the bottom. Overall exactly same configuration as OEM reg.

UPDATE: I've just saved a picture to the gallery - it's off ebay for some kit for Subaru - the significant thing is the regulator ON THE FRONT OF THE BOX - look close and you'll see that regulator would indeed be a straight bolt on for EF - it's the one I described above and has an O ring spiggot and the bracket to take 2 bolts the way EF OEM reg is fitted. I have searched and searched and haven't found the actual regulator itself yet.

[Spork]

Lowering or raising the fuel pressure will affect the injector spray patterns. Also it's pretty crude especially if you arn't doing it with a wide band O2 sensor. A bit like turning the dizzy for spark advance/retard. Your full load/wide open throttle might be ok but your idle and low load might be stuffed. And you won't even know untill your engine blows up!

If you don't have enough money for a proper form of engine tuning then you not going to buy a wide band O2.

[EDXR8]