Fuel Pressure Reg setting?
 

Just had a fuelab fpr installed on the car and was told the standard pressure it has to be set at is 3bar,it has been set to this or just slightly under it but this is when the engine is on idle tick over,is this correct? as the pressure goes up above 3bar on the gauge when the accelorater is pressed.:confused:

It should be 3 bar. You need to take vac pipe off, and set it to 3 bar, when you put vac pipe it should go down to about 2.7 bar. All this is when car is idling.

What mr chips said.
I would stay off boost until mapped though.
Simon

Thanks fellas,just wanted to make sure.:)

What can an adjustable FPR's pressure - specifically, the Lateral Fuelab 3-port - be upped to to, so as to persuade any given injector size to have greater flow than their nominal rating? 3.5bar...4 bar? What?

Depends on how much boost you intend to run, as the boost pressure is added to the base fuel pressure.

Circa 6.5 Bar total on a Fuellab IIRC

You need to be careful if running much over 3.5 bar (no Vacuum) static on stock rubber fuel lines.

Great info FB, cheers. Interesting too.

Can you tell me what effective cc:-

a) 440cc would flow at when set at 3.5bar static, and
b) 550cc at 3.5bar static...

Ask Mark @ Lateral for a definative answer, but...

a - circa 470-480cc
b - circa 590-600cc IIRC

You'll reach a point where upping the pressure gives diminishing returns on flow..

Increased pressure will also make very slight changes to lag times, due to increased pressure on the fuel injector's operating valve

Thanks a lot.

Is lag time the time taken between the valve opening and fuel atomisation occuring, or something?

If the pressure's increased, will the lag time decrease then?

I apologise for my ignorance.

It's the time taken between the ecu commanding the injector to open, and the injector actually opening

Of course, of course.

Sorry. :o :Whatever_

Mine only managed 392 bhp at 4 bar static on std "pinks".

HTH

dunx

Pinks are New Age 550 TFs, aren't they?

At 4-bar static, you're looking at around 'em flowing up to around 630cc, right? (certainly over 600cc). Surely that's enough for seeing up to 500bhp - maybe more?

Was it defo the pinks holding you back?

it doesn't always work like that and what something will do on paper varies in practice sometimes.

Sure Simon, I getcha.

IIRC, Simon saw around 94% injector (DUTY CYCLE ?)

dunx

What do mappers 'like' to achieve for IDC? (about 88-92% I think I've read, as posted by a specialist).

I think Simon told me you can run inj. at 98% IDC, if you really need/are 'forced' to! The available remaining 2% headroom is, allegedly, sufficient to cover any fuelling anomolies(?).

ecu may want to add extra fuel under certain circumstances, but I'm not going to put my neck on the block....

( Add extra fuel as a coolant ? )

dunx

P.S. The reason I say this is that when std mine would heat soak the TMIC on a run and drink a positively scary amount of fuel, whilst getting slower and slower :eek:

That's right - liquid (petrol in this case) obviously has fantastical heat exchaging properties, and adding extra fuel is probably THE best way of instantly combatting det due to that reason.

I'd love to know how the JECS ECU is programmed e.g. in the prescence of det, (and aside from first cutting boost) will it always add fuel first, or will it pull timing first... for example? Be interesting to know its programmed strategy...

it pulls timing via fine learn and coarse learn (advance mulitplier) and the advance map and then will add fuel via the high det fuel map and drop the boost once advance multiplier drops right down.

A car mapped properly should never do more than play with the fine learn imho, assuming ran on the same fuel it was mapped for.

Simon

obviously there is air temp sensor and coolant temp sensor compensations on top of that

Simon

I was always told that ideally 75-80% max duty, but 85% and above isnt uncommon.

Cheers Simon, that explains it then.

Is it a case of 'something's seriously wrong' if it pulls all the fine, then coarse, timing and thus getting into the fuel side of things, then? Or can that scenario happen for a number of reasons, and is therefore 'still okay'?

I tried to keep it simple stupid ;) :D :)

should never happen on a car that is mapped properly.. and this is the OE ecus btw..

Obviously Apexi does none of that etc

Simon

lol fair enough. :D

I suppose what I was trying to get at (badly) was, IF IT DID get into the high det fuel map (putting aside for one moment that it shouldn't), then will the engine be done for? How long can that situation go on for until dead engine? Or is that a factors-dependent, 'how long is a bit of string'-type question?

Or am I simply repeating myself? :lol1: :cuckoo:

(Yeah I know the PFC is fixed, etc. ;)).

I was being cheeky! And only because we have met.
It only takes fpr vac line to split or maf failure as two examples for it to go into that state.
The best solution is to manipulate these safety features in order to save the engine or at least give it a chance.
Hence timing is removed, fuel added and boost dropped.
Simon

Sure. I know it wasn't meant to be 'malicious' - I'm sure that's not in your nature! lol