NefMoto

Hi,

I have installed new injectors. Im going from BOSCH EV14 630cc to BOSCH EV14 1000cc.
I know that i have to recalculate my KRKTE but then im stumbling in darkness.

My plan was first to recalculate my KRKTE and flash the ECU, Drive couple of miles and watch fueltrims and adjust accordinly.
I have also zeroed my KFKHFM without knowing what i do :)

Is there any more "Tips n Trix" and is there a good calculator for calculating KRKTE?

Well first off you need the TVUB and KRKTE,

TVUB is the battery voltage offset injection time and this can be found on the internet or speak to the injector supplier.
KRKTE can be worked out and if you have a look on here you will find the formula but a good starting point is 34/injector cc so you will start up at around 0.034. You should be at around 0.058 on the 630cc
If you have wideband then you can as you log the trims and see whether it needs adjusting. The ecu can trim +/- 25% before MIL shows.

Temin/Teminva are the minimum injector in time

Fkkvs is the fuel system correction and there is a utility on here that can help you with that

Other than that I would really suggest you have a read of S4 Wiki and get to grips with it first before pissing in the wind. Las thing you want is to do it all wrong and bore wash the cylinders and screw the engine before you've even got going!

Did you bother reading the s4wiki page?

It links here
http://nefariousmotorsports.com/forum/index.php/topic,320.msg6774.html#msg6774

which says:
KRKTE = 50.2624*(Liters/Cylinder)/(operating flow rate in cc/min * .684 constant )

BIG Thanks for that answer it simplifyed some things.. I have read the Wiki and also made my readings in forums but i also wanted to achor it here in a thread so i can get help easy in case of missunderstanding the Wiki.. I think the Wiki is good but sometimes i have problems reading it.. I would like it more visual.

I will start off with the tips u gave me and se where I end up.

Visual in what way?  It's a formula.  You cannot make that any more or less visual?

I made this to understand more visual how things are connected. A formula is a subfunction within the function so to speak. That what I mean.. Sorry if I was a bit nonspecific.

Warning this is only a beta made by a "NOOB" !

That kinda doesn't make any sense at all :(

good answer! Thanks.. you have been very informative :)

No seriously, just about none of the arrows or connections are correct.

I don't know what to tell you.. I'm not even sure what YOU think the connections mean :(

For example - LAMFAW has no bearing on TABGBTS
KRKTE doesn't affect LAMBTS or LAMFAW
STFTs don't affect open loop fueling.

TVUB is additive, KRKTE is multiplicative.

TEMIN has nothing to do with KRKTE

AFR actual affects NOTHING in your flow except for STFT, which, as I said, doesn't affect open loop fueling.

It is as if you completely ignored the FR entirely.

First the picture was to show what i mean by "KIND OF" show a visual illustration..  and as i said "Warning this is only a beta made by a "NOOB"".

Now that i have made my point clear you are discussing weather I have made the drawing correct or not".

I didnt anywhere near say that the drawing was correct. My claim was that i have problems understanding some text sometimes and therefore i prefer to make a drawing of my understanding so far.  Well one could say I could just paste in the "Functionsrahmen" diectlly but I like so make it look more simple. I will not argue to update this illustration.

FKKVS is still on the code path too, you may need it here.

Best think about one module at a time re diagrams.  Remember the FR's for a 1.8 at well S4/R4 different code everywhere lol.

My FKKVS: Is set at 1.001 all over the map now just to get a picture how it behave on that. I did this due to a rebuild from returless to Fuelrail with return. I can imagine i have to make some adjutments here.

This is a 24V 3.2 VR6
KRTE now: 0.08680 (630cc +E85) I will run 4bar Fuel pressure and E85.
TEMIN now: 0.5867

http://s4wiki.com/wiki/Fuel_injectors

I get this

3.2L
6cyl
1000cc Bosch Ev14

KRKTE = 50.2624*(Liters/Cylinder)/(operating flow rate in cc/min * .684 constant )
KRKTE = 50.2624 * 0.5333 / ( 1000 * .684) = .0391

Could this be plausible?

Also as i understand TEMIN is the minimum time the injector is allowed to be open.. So this mean that if TEMIN is low i limit the openingtime of the injector. And if High i increase time for injector to be open. Is this a limit to not damage the injector to stabilize the idle if very big injectors.

To se if I have to adjust TEMIN my understanding is to log my fueltrims at idle.. IF fueltrim is say 6% off i will have to correct TEMIN untill i get close to "0" at idle.. (But if LTFT is only off scale at idle it could be possible that TVUB is the value to adjust).

TEMIN is the minimum effective pulsewidth.

Excluding dead time, this is the minimum pulsewidth to keep flow above the knee.

Effective injection time, te_w, will always be >= TEMIN.

Allowing te_w below the knee (TEMIN too low) may cause stalling and too high TEMIN can cause drivability issues and rich conditions.

TEMIN is NOT tuned experimentally based on trims, that is what KRKTE and TVUB are for.

If the required KRKTE and TVUB end up with a te_w that bottoms out on TEMIN (meaning that lowering TVUB and KRKTE no longer solve richness at idle), you can ONLY lower TEMIN if the injector allows it. See the injector specs.

If the injector does not allow it, you may have to increase your idle speed or increase idle torque reserve (to have the motor ingest more air during idle).

This may, however, cause richness on VERY light throttle (decel, part throttle just above fuel cutoff) - you may have to bring in fuel cutoff sooner.

Concur, you need to keep an eye on te_w (iirc and make it above min
n/pw) at idle no need to upwards temin or anything.

Also you can use FKKVS for fine tuning at the end.

KFMESK etc work but I had to re-work the AC compressor maps too and a few other things.

Good and qlarifying info!
*Allowing te_w below the knee (TEMIN too low) may cause stalling and too high TEMIN can cause drivability issues and rich conditions.
*TEMIN is NOT tuned experimentally based on trims, that is what KRKTE and TVUB are for.
*Also you can use FKKVS for fine tuning at the end.

Tricky
*KFMESK etc work but I had to re-work the AC compressor maps too and a few other things.

Sounds like i have alot to tune this spring  ;D  Te most disturbing thing is that i cant use Me7 logger on my ECU.. sucks.. I have to figure out something.


Thanks for guidance so far !

You can also use KFLF for fueling adjustments. Technically FKKVS is for returnless systems (at least according to the FR)... But there is more than one way to skin a cat, and plenty of people use FKKVS in fuel return systems.

If you read the FR I'm sure they mention it's value in return systems,  definitely another way as you say.   Personally I think it's a good map for dialing in injectors/fuelling. 


Either way the Audi  code uses it but alas stock files are all ones that I've seen for the S4 anyway.

Well IMO the reasoning is that your fuel system (if not returnless) should be pretty damn linear outside of very low loads, so any issues you have with fueling are NOT fueling related, they are MAF etc. related.

If you DO have non-linear fueling, your hardware is broken, or you have a returnless system.

By fixing things in FKKVS you are hiding calibration problems in load calculation, etc..

If you fix it in KFLF and MLHFM (assuming your fuel system is working properly), as a side benefit you've got your non-fuel related calibration right.

Good explanation there wiki?!  I've mostly worked on return less so maybe I am bias :)

I've not included it in the wiki because I think it is a matter of opinion, and I don't want to mislead people into thinking there is a single way to do things!

If FKKVS works, it works.

Good point!  Different ways like you said.

Not disputing a word but though I'd add this since it's comes fom an FR I have:

Thanks for declaring that.. I have been lying sleepless at night thinking exact about that! My FKKVS table is now 1.001 because im almost certain that my fuelsystem is linear now with return line and a Bosch 4bar FPR.

Now im a bit uncertain when KFLF is the table to adjust and when MLHFM is the table to corrent... What is it that points me to use KFLF or when to use MLHFM? My understanding is that KFLF is a correction table under part load and MLHFM is due to modified air intak that is so modified from stock that it need a touch up.  Like me going from a NA engine to an turbo.. Now the air must pass trough various pipes and an intecooler and so on.. What is a good method of dialing in the MLHFM and the go over to KFLF?

When I think after now.. I should have calibraed mt MLHFM when the engine was almost stock. Then i would have seen the deviation clearly.. I should have modified the car one step at the time derriving from stock calibrated engine.