VEMS and Ford light green injectors roughly at idle

[GazzaG60]

i just popped the 630's in exchanging them for the standards. set req_fuel and it run sweet. im not **** on the ramp-up for sure. if its works no need to fix.

my view is this.

req_fuel is important as the constant applied to the injectors. the formula applied to get the fuel out uses ve and req_fuel. therefore changes to ve will compensate for the wrong req_fuel.

on other ecu's there is a target figure for say middle of the map. on LINK systems thats 60. im not aware of a figure on vems.

[A80Avant]

so it is all not too mathematical then. Im with Gary on this one. Req_fuel is not hugely important,unless it is so wrong that you end up not having numbers to put in the bins >255 or something.

on the 630cc injectors i plan to use the correct ramp up for the siemens and get the req_fuel values as convinient as possible as i plan to redo the VE table from scratch, rather than just my existing one.

[Jamo]

It is mentioned on the wiki by Marcel

s2central or sjmautotechnik talks about differences between AAN and 3B. (TODO: find the link).

* fuel pressure
o AAN FP=4bar
o 3B FP=3.5bar

That means sqrt(4/3.5) = 1.07, so 3B injectors flow 7 percent less, therefore require req_fuel of 7% more. (also roughly 7% more cranking pulsewidth).

[GazzaG60]

there are benifits to a high or low req_fuel.

the ve table is where we compensate and to and extent accel enrichment.

i calculated wrong on mine. i used the rating at 3bar. it runs fine. mine req is like 4.8 and i think it should be down near the 3 mark.

i dont get too hung up on req fuel. linkecu for instance uses numbers 1-5 IIRC in early versions so not much variation. lots of time mapping brings in inline.

[A80Avant]

if that is the case, why isnt it mentioned anywhere in VEMS or elsewhere about the fpr used?

dont worry as to how i will do on higher firmwares. And believe me, req_fuel is not the only thing you need to have nice running. Billman has been running 630cc injectors as well as others with no issues, + with wrong ramp up times as well. I have no problems with idle, or any other map bin on that matter as well. Good for you, you found what your RC injectors flow.Although you are changing them now. If it was that simple to get everything perfect with req_fuel, everybody would have perfect results.

it does sound more logical to put the flow rate at its fpr, i agree, but if the equation is set in the hardware with the advertised spec of the injectors,i believe it is something that VEMS hardware figures out on its own to make the proper mixtures. As i said, it is not as simple to say 440@3bar = 508@4bar because it is not.

[Jamo]

im sorry, but i dont think this is right.
req_fuel is the calculation of injectors @ their specification, NOT the fpr used.At least that is what VEMS and efiexpress have on their websites.

besides as i have been told, injectors 440cc @ 3bar are not calculated with a simple equation to find their flow @ 4bar or 3.8bar because it is not analogous.

So 6.49*(2226/5/440)=6.5 OR 4.9 (if you want 75%).

thats what i use at least and got the 6 instead.

of course, i could be wrong which is why im getting DC over 100% on the log viewer, but hey,that is what i was told.
if the fpr bar needs to come into play, then we need the excact equation, or a flow meter to see what it flows at the fpr bars to put it in the equation

Really, well we'll see when you get to the higher firmwares which really heavily on the req_fuel for starting.

The flow was calculated using the RC calculator who make injectors, I think they know a thing or two http://www.rceng.com/technical.aspx

The req_fuel is the injector open time to make stoich if your injectors are rated at 3 bar but your fuel pressure is 4 bar you injectors have to open for less time as they will flow more for that give point in time, so yes you must adjust the req_fuel to suit.

[A80Avant]

im sorry, but i dont think this is right.
req_fuel is the calculation of injectors @ their specification, NOT the fpr used.At least that is what VEMS and efiexpress have on their websites.

besides as i have been told, injectors 440cc @ 3bar are not calculated with a simple equation to find their flow @ 4bar or 3.8bar because it is not analogous.

So 6.49*(2226/5/440)=6.5 OR 4.9 (if you want 75%).

thats what i use at least and got the 6 instead.

of course, i could be wrong which is why im getting DC over 100% on the log viewer, but hey,that is what i was told.
if the fpr bar needs to come into play, then we need the excact equation, or a flow meter to see what it flows at the fpr bars to put it in the equation

[GazzaG60]

ive seen duty over 100% too. not sure if it calculates duty or measures it.

personally id load the known working map back in and change the req_fuel to mathc the change in injector size. sounds like the ve table has gone all out. or you have timing issues.

also if you have bogged it down with fuel you may need to clean the plugs to get it running nice again. otherwise it will just chug.

get a small brush and some brake cleaner and scrub un clean.

[Jamo]

440 cc at 3 bar = 508 cc at 4 bar

req_fuel = 6.49 * 9 ( 2226 / 5 / 508 ) = 5.7 multiply by .75 = 4.2 or 4.3 rounded

So your req_fuel is actually correct.

What firmware are you running?

[Rocco]

and wich are your turbo specs Thomas??

RS2 turbo +7A regulator....etc etc?? with Vems of course

ABY or 3B??

good luck from an other Tomas

[th.b.w.]

I will change the Req_fuel later and see what happens...

Thomas

[A80Avant]

yes, that is what i said. my req_fuel is set to 6.

I have no problems, although im looking into something insteresting... I do get for some reason on the logs the injector DC to go well over the 100% (it has gone to 117% once) even though the amount of fuel injected is less than what it was in the past.

For example, in the past, when tuning, i had even up to 0.70 lamda after 5500rpm.I never had problems
Now i have taken that to 0.78 lamda but the injector DC seems to be going over 100% after 5800 or 6000rpm for some reason. I dont understand why.

[th.b.w.]

Hy,

@A80Avant, do you run these light green injectors ?

Thomas

[A80Avant]

i run 440cc injectors with 3.8bar fpr with no problems whatsoever

[th.b.w.]

Hy,

req_fuel setting are 4.2...., the VE table goes from 67 at idle to max.145 at full boost.
Pulsewith at idle is 1.8-1.9ms...


Thomas