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Author Topic: Bosch EV14 Injector Migration  (Read 172928 times)
nehalem
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« Reply #30 on: June 10, 2011, 09:49:25 AM »

550cc ev14's, 85mm maf, 4.0 bar (stock) fpr

stock tvub
krkte = .11

ltft reads 0.2% after



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julex
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« Reply #31 on: June 10, 2011, 10:39:41 AM »

550cc ev14's, 85mm maf, 4.0 bar (stock) fpr

stock tvub
krkte = .11

ltft reads 0.2% after





That's strange. 530cc @ 4bar flow almost 2x as more as stock injectors yet krkte delta is not 1/2 of original stock value.

I guess you have something heavily compensating for this in other maps as well as for wrong TVUB...

That's why every car needs to be custom tuned to work right. There are numerous maps you can adjsut things for other places having wrong values Smiley
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wickster
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« Reply #32 on: June 13, 2011, 01:27:54 PM »

Have I been going the wrong way with KRKTE. Should I be increasing KRKTE from the stock value of .0977 ms/% instead of decreasing it? 
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'01.5 Audi S4 2.7T - 6MT - K04s - ASP 85mm Hitachi - 49lb Delphi
Tony@NefMoto
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« Reply #33 on: June 13, 2011, 04:02:33 PM »

Have I been going the wrong way with KRKTE. Should I be increasing KRKTE from the stock value of .0977 ms/% instead of decreasing it? 

When going to larger injectors you need to decrease KRKTE. KRKTE is the conversion from load to injection time, so with larger injectors you need less injection time to meet the lambda requirement at the same load.

You should also check the constant for the minimum injection time to make sure you aren't hitting that.
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wickster
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« Reply #34 on: June 14, 2011, 04:57:30 PM »

Do you know the variable name for that constant?
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'01.5 Audi S4 2.7T - 6MT - K04s - ASP 85mm Hitachi - 49lb Delphi
julex
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« Reply #35 on: June 14, 2011, 07:42:58 PM »

TEMIN
TEMINVA
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wickster
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« Reply #36 on: June 16, 2011, 06:15:19 PM »

http://www.injectordynamics.com/
Paul from Injector Dynamics has given me the following data.

The volumetric flow rate on gasoline at 125F is 628cc/min.

The battery comp/dead time/offset/latency/lag is as follows:

Units are volts and microseconds.

8 - 2500
9 - 1940
10 - 1520
11 - 1270
12 - 1100
13 - 935
14 - 800
15 - 690
16 - 600



Albeit it looks about right, unfortunately is proper but only for 2.7bar fuel pressure which is what everyone tests injectors at...

Check this:

http://www.boschdealer.com/specsheets/0280158117cs.jpg

What's important on this spreadsheet is FNPW_OFFCOMP table which tells you how much you need to multiply each dead time at its voltage to get real value for the FPR you're running.

Vast majority of people need to use 60.03 (for 4bar FPR) value and multiply the original FNPW_OFFSET (pretty close to values you listed) byt the multiplier.

Here is a catch. The table has errors, I think, since values for 30.02 and 60.03 since they don't follow data pattern. Check other injector calibration sheets on the site, I am fairly sure this to be true... anyway, 30.02 should have 0.8564 and 60.03 1.2638

I tried tuning with the base values but was getting really strange O2 corrections for idle/part throttle with things getting more in-line as the injector on time was getting longer indicating that the injector lag was smaller and smaller in respect to on-time. I am running 1000cc ev14 injectors so any timing discrepancy like that gets exaggerated on my set up. I plugged modified (for 3bar FPR I have) values and now I am dead on with corrections.

I may be calculating this incorrectly for my 550s.

My TVUB values look like this after a little number crunching and a quick graph.

Volts   MS
7.04    4.666
10.06   1.813
12.03   1.314
14.08   0.997
17.88   0.805

I'm going to go try this now, though I'm not expecting good results. Currently running KRKTE of 0.058 with -10% Partial LTFT and a 0% LTFT at idle. I figured now that my KRKTE is close I would input a proper TVUB and then adjust from there again.

My TEMIN is 0.501 and my TEMINVA is 0. Minimum injector on time appears to be running 2.38 ms at idle. An online reference says min injector ontime for these injectors is around 0.704 ms.
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'01.5 Audi S4 2.7T - 6MT - K04s - ASP 85mm Hitachi - 49lb Delphi
wickster
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« Reply #37 on: June 16, 2011, 06:16:39 PM »

Also, the car ran great and started great when warm but it idled very rich it seemed during cold start. Not sure where to start there, have to do some research.
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'01.5 Audi S4 2.7T - 6MT - K04s - ASP 85mm Hitachi - 49lb Delphi
nehalem
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« Reply #38 on: June 29, 2011, 01:23:12 PM »

the tabgbts on my tune is set to 375.  is it possible that i'm not seeing issues with krkte/tvub because the tune is being forced to operate off the egt maps (kflbts / kffdlbts) due to the lowered tabgbts?

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nehalem
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« Reply #39 on: July 21, 2011, 12:22:41 AM »

Assume this (http://www.boschdealer.com/specsheets/0280158117cs.jpg) to be accurate and we already know a 4-bar pressure regulator is 58.02 psi.  Therefore FNPW_OFFCOMP has a theoretical value of:  1.1852.

Using the same decimal accuracy as the calibration sheet:
1.1852 = 1.2179+(58.02-54.96)*(1.1638-1.2179)/(60.03-54.96)

In MATLAB I entered the FNPW_OFFSET values and fit a shape-preserving spline.
You can see the attached graph below to view the curve-fit.
Interpolated output from the curve below is naturally multiplied by 1.1852.

Volts    MS
7.04     3.865
10.07   1.678
12.04   1.227
14.08   0.926
17.88   0.779

Now for KRKTE, the theoretical value is pretty simple to calculate.
KRKTE = 50.2624*(Liters/Cylinder)/(operating flow rate in cc/min * .684 constant )
KRKTE = 50.2624 * 0.4452 / ( 615 * .684) = .0532

These are the values I'm going to start my K04 tuning with using the rinse/repeat process after I get a wideband installed (based on the stock m-box).  Could somebody please verify what I've done above?  Thanks guys.
« Last Edit: July 21, 2011, 01:19:28 AM by nehalem » Logged
NOTORIOUS VR
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« Reply #40 on: July 21, 2011, 01:51:50 PM »

I have no idea if your math is correct for your TVUB...

but did you use the flowrate of your injectors for n-heptane? if not it won't be right on...

either case, I'm sure they're fine as starting values... and you can tweak them from there once you get the car started.
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« Reply #41 on: August 24, 2011, 10:24:14 PM »

Note that I have the WRONG scaling in my XDF mappacks.

http://nefariousmotorsports.com/forum/index.php/topic,935.msg8064.html#msg8064

I will be releasing an update soon to fix this.
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« Reply #42 on: August 25, 2011, 12:22:07 PM »

I figure I'd post this here as well (just posted in my thread) since it has to do with Bosch injectors..

Found this very well laid out and detailed .xls that shows pretty much every Bosch injector and n-hep flow rates.

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nehalem
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« Reply #43 on: August 31, 2011, 12:04:32 AM »

here's the theoretical way to calculate krkte straight from some bosch manual:


all of the q-stat values in the above excel sheet are calculated for 300 kilopascals which is 43.5 psi.  to convert the operating pressure to what a standard b5 s4 would use, we need it for 4-bar, which is 58.0 psi.  to do the conversion:  q-stat * sqrt(58.0/43.5)
==q-stat @ 300kPa * 1.1547     for my application =   532 * 1.1547  = 614 cc/min

that's 614 cc/min of n-heptane...
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PovGRide742
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« Reply #44 on: January 28, 2012, 05:27:45 PM »

nehalem,

Wouldn't it be more accurate to use the equation QSTAT * sqrt(4/3) rather than QSTAT * sqrt(58.00/43.50), being that what the equation is trying to achieve is that the initial psi is 75 percent of the target psi. I know the equation will work out the same, but 58 and 43.5 are rounded off where as 4 and 3 is exact... also making calculations easier?

Brett

PS... don't take this reply as a smart-ass one, I've been learning a ton off your posts!
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