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Author Topic: Help with KRKTE  (Read 11593 times)
masterj
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« on: February 28, 2012, 04:50:49 PM »

Hello people!
Could someone confirm if my KRKTE factor is 0,000167 or 0,000111?
Thanks
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julex
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« Reply #1 on: February 28, 2012, 06:56:23 PM »

I've seen ols files for similar platform having both factors. What helps is to enter this stuff in hex, this way you'll avoid round up/down issues as well.

Anyway, why are you stressing Smiley? If you know what your injectors are (you better) simply divide whatever you see in the file (regardless of factor) by how many times new injectors are larger than old and use that value. It should be spot on.
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masterj
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« Reply #2 on: February 29, 2012, 08:13:32 AM »

I've seen ols files for similar platform having both factors. What helps is to enter this stuff in hex, this way you'll avoid round up/down issues as well.

Anyway, why are you stressing Smiley? If you know what your injectors are (you better) simply divide whatever you see in the file (regardless of factor) by how many times new injectors are larger than old and use that value. It should be spot on.

I would prefer to be as precise as possible and also define my file properly
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julex
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« Reply #3 on: February 29, 2012, 11:24:53 AM »

I would prefer to be as precise as possible and also define my file properly

"111" seems to be prevalent but then again, even the original OLS have two different values so it is hard to say which one is right.
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professor
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« Reply #4 on: February 29, 2012, 03:04:00 PM »

0.000111 with KRKTE value of 0.10478 as i see.
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masterj
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« Reply #5 on: February 29, 2012, 03:58:16 PM »

found the correct value and it is 167. How I found it? Just calculated stock injectors and compared them to stock KRKTE value Wink
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masterj
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« Reply #6 on: March 01, 2012, 03:49:55 AM »

Another problem with KRKTE... I have 1.8T with 382cc injectors. I calculate my KRKTE to 0.08565. Now if I put this number into KRKTE then my car has hard time even keeping idle. Maybe my calculations are wrong? Also I have 1s in both KFKHFM and FKKVS just to remove possibility of bad corrections

Also at part throttle my wideband corrects mixture +25%! Should I fix that or is there a possibility that I have fuel leak somewhere?
« Last Edit: March 01, 2012, 04:09:10 AM by masterj » Logged

julex
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« Reply #7 on: March 01, 2012, 07:16:28 AM »

Another problem with KRKTE... I have 1.8T with 382cc injectors. I calculate my KRKTE to 0.08565. Now if I put this number into KRKTE then my car has hard time even keeping idle. Maybe my calculations are wrong? Also I have 1s in both KFKHFM and FKKVS just to remove possibility of bad corrections

Also at part throttle my wideband corrects mixture +25%! Should I fix that or is there a possibility that I have fuel leak somewhere?

What are you trying to do, exactly?

How I would approach the KRKTE issue is not to rely on anybody's values. I would take stock tune, look at its KRKTE and find out how much stock injectors flow. Then  I would take my replacement injectors and divide their flow by stock flow.

Say the aftermarket injectors are 600cc and stock are 300cc. So my new injectors flow 2.00 times more.
If my original KRKTE was 0.075 for examaple, I would now divide 0.075 / 2.00 = 0.0375
Enter 0.0375 into KRKTE window and this is your rough starting value. Drive car around and adjust if you see corrections.

It doesn't matter what multiplier you're using for visual interpretation as you're not changing definitions of KRKTE during this procedure. If multiplier bothers you, just copy the HEX value of the call into calculator, convert to decimal, divide by KRKTE value and convert back to HEX. Enter that into the cell. Done. No multipliers involved.

The problem with your approach is that you're calculating stuff from some theoretical values that don't take under consideration real life physics so they will always be off...especially if you're not sure if your KRKTE multiplier is even right!
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masterj
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« Reply #8 on: March 02, 2012, 06:17:23 AM »

What are you trying to do, exactly?

How I would approach the KRKTE issue is not to rely on anybody's values. I would take stock tune, look at its KRKTE and find out how much stock injectors flow. Then  I would take my replacement injectors and divide their flow by stock flow.

Say the aftermarket injectors are 600cc and stock are 300cc. So my new injectors flow 2.00 times more.
If my original KRKTE was 0.075 for examaple, I would now divide 0.075 / 2.00 = 0.0375
Enter 0.0375 into KRKTE window and this is your rough starting value. Drive car around and adjust if you see corrections.

It doesn't matter what multiplier you're using for visual interpretation as you're not changing definitions of KRKTE during this procedure. If multiplier bothers you, just copy the HEX value of the call into calculator, convert to decimal, divide by KRKTE value and convert back to HEX. Enter that into the cell. Done. No multipliers involved.

The problem with your approach is that you're calculating stuff from some theoretical values that don't take under consideration real life physics so they will always be off...especially if you're not sure if your KRKTE multiplier is even right!

Tried the proportion thing with KRKTE. Got the number very close to the one I previously had +10%. Idle is OK, but at part throttle and woot still needs +25% of fuel...

Maybe my FPR is stuck or something?

Basically my only way to *fix* this problem is to add 25% to FKKVS map at higher rpms, but that is surely wrong thing to do. I need to understand why the f*** there isn't enough fuel at higher loads that idle...
« Last Edit: March 02, 2012, 07:44:36 AM by masterj » Logged

julex
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« Reply #9 on: March 02, 2012, 06:38:16 AM »

keep in mind that if your FPR is 4bar and you know how much the factory injectors flow at that pressure, the new injectors will have their rating expressed at pressures of 3 bar, not 4 bar. You need to add about 16% to 3bar rating to obtain 4bar flow equivalent.
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masterj
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« Reply #10 on: March 02, 2012, 08:13:40 AM »

keep in mind that if your FPR is 4bar and you know how much the factory injectors flow at that pressure, the new injectors will have their rating expressed at pressures of 3 bar, not 4 bar. You need to add about 16% to 3bar rating to obtain 4bar flow equivalent.

You're right. I've completely forgot about fpr differences... Gonna update KRKTE and see if that helps Smiley
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julex
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« Reply #11 on: March 02, 2012, 12:12:29 PM »

ok  Wink

And while at it, TVUB is also expressed @ 3bar. 4bar could be anything but a good rule of thum is to add about 26% as a starting point, but that's for ev14 injectors. Others might be a bit more or less, I saw figures anywhere from 10 to 30% from going to 3bar to 4bar. It is heavily dependent on how much the injector flows. 10% is true for 200-300cc injectors, 26ish for 700cc and 1000cc will be 30% plus.
« Last Edit: March 02, 2012, 12:16:37 PM by julex » Logged
masterj
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« Reply #12 on: March 02, 2012, 03:29:31 PM »

ok  Wink

And while at it, TVUB is also expressed @ 3bar. 4bar could be anything but a good rule of thum is to add about 26% as a starting point, but that's for ev14 injectors. Others might be a bit more or less, I saw figures anywhere from 10 to 30% from going to 3bar to 4bar. It is heavily dependent on how much the injector flows. 10% is true for 200-300cc injectors, 26ish for 700cc and 1000cc will be 30% plus.

Thanks, now that is something new to me. Never thought that injector lag time depends on fuel pressure... Smiley

Logic test:
My TVUB now is (from 3bar datasheet):
8v - 2.33
10v - 1.62
12v - 1.20
14v - 0.92
15v - 0.82

Injectors are 382cc @ 3bar. So mathematically I should change these values by ~12%. Now If I understand everything correctly I should lower the injection lag time because of bigger pressure and that means lowering values by 12%?? Smiley
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julex
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« Reply #13 on: March 02, 2012, 06:56:49 PM »

the opposite. When we are talking injector lag, it is the amount of time the injector needs to work against fuel pressure to open a valve at a given voltage.

The more voltage, the more power the injector can generate and that's way it takes less time with higher voltage. On the opposite side of equation, you have the fuel pressure. The more pressure working against the valve, the slower the valve components move and therefore the longer it takes them to open.

lower pressure or higher voltage = quicker valve = less lag
higher pressure or lower voltage = slower valve = more lag
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masterj
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« Reply #14 on: March 03, 2012, 02:07:12 AM »

the opposite. When we are talking injector lag, it is the amount of time the injector needs to work against fuel pressure to open a valve at a given voltage.

The more voltage, the more power the injector can generate and that's way it takes less time with higher voltage. On the opposite side of equation, you have the fuel pressure. The more pressure working against the valve, the slower the valve components move and therefore the longer it takes them to open.

lower pressure or higher voltage = quicker valve = less lag
higher pressure or lower voltage = slower valve = more lag

Got it! Thanks
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