lag time fuel injector correction

[s13silvia123]

i need the right lag fuel injection correction for my Power FC to run deatschwerks 740cc injectors. "the purple injectors"

i've been looking at numerous threads to correct this and it seems like it doesnt work nor the fuel injector formula will work with this.

if you have the correct lag time for these fuel injectors for the PFC please post it for me.

i would need water temp injection value corrections as well.

[Darius]

E-mail Deatschwerks. They have a list of them. In case you are lazy, their values for those 740cc purple injectors are as follows:

6V = 5.00
7V = 3.90
8V = 3.23
9V = 3.13
10V = 2.96
11V = 2.75
12V = 2.56
13V = 1.97
14V = 1.66
15V = 1.40
16V = 0.98
17V = 0.84

You're welcome!

[Darius]

And water temp injection values should not matter.

[s13silvia123]

youre saying this is the Injector Data settings or the Ignition/ injector correction setting

i just emailed deatschwerks for more info.

thanks.

[rc1honda]

E-mail Deatschwerks. They have a list of them. In case you are lazy, their values for those 740cc purple injectors are as follows:

6V = 5.00
7V = 3.90
8V = 3.23
9V = 3.13
10V = 2.96
11V = 2.75
12V = 2.56
13V = 1.97
14V = 1.66
15V = 1.40
16V = 0.98
17V = 0.84

You're welcome!

So does that mean thats it's (2.56-the old lag time) becuase he is on a 12 volt system?.

[s13silvia123]

So does that mean thats it's (2.56-the old lag time) becuase he is on a 12 volt system?.

thats why i'm asking him cause i dont seem to understand where to input this data.

[Darius]

There is a range in the PFC input for like 6, 8, 10, 12, 14, and 16V or something like that. It will adjust the lag settings if the voltage varies in case the alternator begins to fail or the charge system is not running at 12V or 14V, whatever.

You should input those numbers straight up, not try to subtract them from the stock PFC numbers. You'll note that the DW lags are probably higher than the PFC numbers and this is because DW injectors are refurbished.

The water temp settings matter, but they are a percentage of the injector duration so they can stay the same unless you feel that they need to be changed. I would recommend against changing them until you get the injector lag input and reset the idle on the PFC, etc.

Try to change as few things as possible and evaluate the effects of each change.

[slider2828]

I ran a Lag time of 0 when I was using the 600cc based KA injectors.... from what I remember... How do you enter the absolute value in the PFC, if under injector settings its subtract or add just for the difference?

You can't the value they give you and trust me I have the same table is based on their testing.

You have to input it into an injector equation, these numbers are empirical numbers from testing and is arbitrary to the PFC understanding...

If your 740cc injectors your lag time should be 0 because they are rebased 370's.... So enter 0.... no lag time changes needed for SR PFC

For future reference redtops are rebased KA injectors and lag times should be adjusted accordingly to difference between KA and SR injectors, but overall -4 or -2 usually works cause the lag time isn't that different.

[s13silvia123]

i'm gonna try it to see what happens just hoping i'm not gonna flood the motor with fuel. then i'll get back to this thread again.

[Darius]

I ran a Lag time of 0 when I was using the 600cc based KA injectors.... from what I remember... How do you enter the absolute value in the PFC, if under injector settings its subtract or add just for the difference?

You can't the value they give you and trust me I have the same table is based on their testing.

You have to input it into an injector equation, these numbers are empirical numbers from testing and is arbitrary to the PFC understanding...

If your 740cc injectors your lag time should be 0 because they are rebased 370's.... So enter 0.... no lag time changes needed for SR PFC.

I have to disagree with you that the PFC numbers are arbitrary. In datalogit software, the heading on the injector lag settings say "Inj Lag (ms) vs BatV".

Hence, you need to enter the injector lags in milliseconds from the DW table since they are also in ms. You could probably get away with 0 ms for all lag settings but the injectors will be firing later than optimum ~2ms late. The car will run, but it won't run as well as if the lag settings are matched with the injectors.

[lok]

Are you trying to get your car drivable so you can have it tuned? If not then

Do you have a base map written for your car?

Do you have a wide band installed?

You cannot just plug in these values. IE z32 maf, 740cc injectors and expect it run like stock.

[s13silvia123]

i just need the car drivable so i can get tune.

you dont need to worry about me having this and that cause i already have the necessary things to make my car run right.

base map i already know where i can get it from but i need two base maps. each is for different reasons.

last but not least i know i cant expect to run like stock with all that stuff youre saying etc.......................

[rc1honda]

There is a range in the PFC input for like 6, 8, 10, 12, 14, and 16V or something like that. It will adjust the lag settings if the voltage varies in case the alternator begins to fail or the charge system is not running at 12V or 14V, whatever.

You should input those numbers straight up, not try to subtract them from the stock PFC numbers. You'll note that the DW lags are probably higher than the PFC numbers and this is because DW injectors are refurbished.

The water temp settings matter, but they are a percentage of the injector duration so they can stay the same unless you feel that they need to be changed. I would recommend against changing them until you get the injector lag input and reset the idle on the PFC, etc.

Try to change as few things as possible and evaluate the effects of each change.

Well when doing this from the commander there are no numbers nor anyplace to to input the table. What you have to do is correct for injector size and latency. You do this by:

Dividing old injector size by new injector size the multiplying by 100. So
370/740*100 for example will give you 50%.

Then you have to correct for latency which in milliseconds only can be corrected be every .02ms. You do this by subtracting new latency by old latency. For example .85-.25= 0.6 ms. Then you continue to input these values for each cyclinder.

Now my earlier question asked do you use the latency time value in the 12 volt position to make your corrections because the car uses a 12 volt system?

Wheres Steve Shadows at lol.

OP here is a guide to help u on your way http://paulr33.skylinesaustralia.com/docs/powerfc-faq/powerfc-faq.htm#5

And here is what is says from that guide:
Configuring larger injectors into the PowerFC is quiet simple and takes only a few moments. You need to know the following information before you can continue


Current injector size
Current injector latency
New injector Size
New injector Lag time

To work out new INJECTOR correction and latency;

Old SIZE / New Size = Correction
New Latency - Old Latency = Latency Correction

John plans to install 600cc injectors into his RB26 VL Turbo. The following figure's are used;

444 / 600 = 0.74 * 100 = 74.0%
0.81 - 0.77 = +0.04 msec

So he would enter 74% for correction and 0.04 as new latency

Once you have switched to larger injectors you should still check your AFR's with a wideband to ensure they are safe and acceptable.

[ILoveJDM]

rihonda is correct, this topic is about new injector lag times vs the old injectors

darius, youre talking about injector lag time variables calculated after the base lag time.

[slider2828]

Have you even looked at the PFC Lag time values? I dunno about the datalogit software, which might calculate for the base timing. But PFC through the commander is base time +/- your current injectors. Why also why would you through out an arbitrary number of ~2ms? What is that based on?

For a fact I asked DW specifically about these printed lag times and yes its for 12v actually it should be 13.4 - 14v cause your car does not run on 12v.... obviously if datalogit allows you to change the base timing across all voltage then awesome, but not everyone has this software or know its calculation.... If you must know, ask DW for the calculations, but he admits that PFC chooses arbitrary numbers...

Below is an email by Mike Deatsch.... and he explains your lag time numbers is not true lag times chose by Apex'i.....

"That would be .71ms, and that is not the true latency time for that injector. .71ms is not a possible dead time for a high impedance injector. It is simply the derived number the ECU uses.

We know of the formula below, but can not be sure that it is 100% correct. But it give you an idea of how the ECU might display the dead time it is using.

(X + ((175-Vx/0.08 ) * (Y/256)))*0.01 where X = value used by ECU (theatrical value @ 14V) and Y corresponds to battery voltage."

With that said, what is meant by lag time in PFC terms and what DW says is different.... I tried the formula but even he says its not 100% right and this value is also written in some other automtive sources, but its not really applicable.

Hence just use lag time = 0. My car was tuned by steve shadows and using rebased KA injectors at 600cc, my lag time was around -4 or -2, don't remember... but it doesn't make sense and its all based on tuner....

[Darius]

Have you even looked at the PFC Lag time values? I dunno about the datalogit software, which might calculate for the base timing. But PFC through the commander is base time +/- your current injectors. Why also why would you through out an arbitrary number of ~2ms? What is that based on?

For a fact I asked DW specifically about these printed lag times and yes its for 12v actually it should be 13.4 - 14v cause your car does not run on 12v.... obviously if datalogit allows you to change the base timing across all voltage then awesome, but not everyone has this software or know its calculation.... If you must know, ask DW for the calculations, but he admits that PFC chooses arbitrary numbers...

Below is an email by Mike Deatsch.... and he explains your lag time numbers is not true lag times chose by Apex'i.....

"That would be .71ms, and that is not the true latency time for that injector. .71ms is not a possible dead time for a high impedance injector. It is simply the derived number the ECU uses.

We know of the formula below, but can not be sure that it is 100% correct. But it give you an idea of how the ECU might display the dead time it is using.

(X + ((175-Vx/0.08 ) * (Y/256)))*0.01 where X = value used by ECU (theatrical value @ 14V) and Y corresponds to battery voltage."

With that said, what is meant by lag time in PFC terms and what DW says is different.... I tried the formula but even he says its not 100% right and this value is also written in some other automtive sources, but its not really applicable.

Hence just use lag time = 0. My car was tuned by steve shadows and using rebased KA injectors at 600cc, my lag time was around -4 or -2, don't remember... but it doesn't make sense and its all based on tuner....

AHH I see. You guys are trying to tune a PFC with the hand controller. Hopefully your tuner has datalogit or I'd find one who did. You can't tune an engine via the hand controller.

The datalogit software must be different as far as what it allows for inputs. I'll check out what my hand controller has for injector lag settings. Either that or maybe it is different because I'm running an RB and the Apexi software inputs are slightly different on the KA.

And 2ms is not an arbitrary number. If you look at the DW chart, 2ms would get you close enough to a satisfactory injector lag for most injectors and system voltages.

[Darius]

Maybe I'm interpreting what the injector lag setting does. i.e. which way it corrects. Is it telling the PFC how long the injector is going to lag and it calculates the correction or is it directly telling the PFC how much earlier it needs to fire the injector relative to the OEM or PFC base settings??

Here is what the OEM/PFC base setting screen looks like:
http://i118.photobucket.com/albums/o118/kasper20/DatalogitLags370ccPFC.jpg

This is with the 650cc DW injector lag settings inserted into datalogit:
http://i118.photobucket.com/albums/o118/kasper20/DatalogitLags650ccDW.jpg

[s13silvia123]

i'm getting frustrated on this. it seems like i'm staying at 75-100% to actually make the motor run. but if i change the setting to 50% the motor wont even start up compare to above.

where's steve shadows when i need him. come jump on this. i'm getting a headache.

[s13silvia123]

AHH I see. You guys are trying to tune a PFC with the hand controller. Hopefully your tuner has datalogit or I'd find one who did. You can't tune an engine via the hand controller.

The datalogit software must be different as far as what it allows for inputs. I'll check out what my hand controller has for injector lag settings. Either that or maybe it is different because I'm running an RB and the Apexi software inputs are slightly different on the KA.

And 2ms is not an arbitrary number. If you look at the DW chart, 2ms would get you close enough to a satisfactory injector lag for most injectors and system voltages.

yes its with the hand controller. so youre saying that 2ms is the closest i'm going to get to run correctly at 100%

[Darius]

Try it with the straight up DW inputs first and see how the engine runs. 2ms won't be 100% correct, but it will probably get the engine to run enough so you can get it to the tuner.

[s13silvia123]

injector duty cycle setting is

1. 100% 0.2ms
2. 100% 0.2ms
3. 100% 0.2ms
4. 100% 0.2ms


i've yet to try other settings but to me at 60% and at 0.2ms is at its best and is able to drive around the block. if i up ms by 0.1-0.3 i've not able to rev pass 4000 RPM

gonna do a little testing to figure out which one is best. but it seems that if i dont run the duty cycle at 100% and go lower than that i run a little richer.

[ILoveJDM]

Maybe I'm interpreting what the injector lag setting does. i.e. which way it corrects. Is it telling the PFC how long the injector is going to lag and it calculates the correction or is it directly telling the PFC how much earlier it needs to fire the injector relative to the OEM or PFC base settings??

Here is what the OEM/PFC base setting screen looks like:


This is with the 650cc DW injector lag settings inserted into datalogit:
http://i118.photobucket.com/albums/o118/kasper20/DatalogitLags650ccDW.jpg


the box with all the zero's is the lag time box for the injectors.

inj vs batv calculation is corrected on top of this value. this is the same as very "___vs___" in the settings tab, those are applied after base value.

the values i used are these, .85ms lag time for new injectors .71 were the 370cc injectors.

inj1 67.2 0.14
inj2 67.2 0.14
inj3 67.2 0.14
inj4 67.2 0.14

[Darius]

Wow, that makes perfect sense. Why doesn't the datalogit software even label that column? WTF?! LOL! I have been completely ignoring it until now.

[s13silvia123]

injector duty cycle setting is

1. 60% 0.2ms
2. 60% 0.2ms
3. 60% 0.2ms
4. 60% 0.2ms

i changed it again. this is the closest that it would run fine with no problem

[slider2828]

if you have 740's it should be 50% at 0.2ms....

also did you change your water or warm up temp? These should be the closest setting... What are the problems that you are seeing when it is setup with 50%?

Yeah the datalogit software is great, but I don't have it lol... Its about 350 or something like that... I just bring my car to steve anyways...

[s13silvia123]

if you have 740's it should be 50% at 0.2ms....

also did you change your water or warm up temp? These should be the closest setting... What are the problems that you are seeing when it is setup with 50%?

Yeah the datalogit software is great, but I don't have it lol... Its about 350 or something like that... I just bring my car to steve anyways...

i tried that doesnt really work out for me. runs pretty rough and doest rev pass 5000 while in neutral.

i would like to bring my car to steve but you guys live half across the country from me. so the only i have to do is get it able to run correctly so i am able to get the car to AMS this spring.

[Groudy]

I want the lag time for the Denso low resistance 1000cc injectors. Anyone knows these too?