NefMoto > Noob Zone > Noob Questions (Moderator: turboat) > KRKTE calculations
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Author Topic: KRKTE calculations  (Read 7552 times)
CQ1
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« on: March 18, 2017, 02:43:32 AM »
Can anyone tell me what i'm doing wrong, because i'm getting sick of this.

Passat 1.8T AWT 150HP 4B0906018CG-0261207215-360306
Stock injectors - 0280156065.
Stock fuel pressure - 4Bar

Stock bin KRKTE - 0,10478 - factor offset 0,000111
Stock bin KVB - 298,59

According some spec's those 0280156065 injectors are 252cc/min @ 3 Bar, according the others 258cc/min, etc.
"Injector Data & Flow Converter" which i found on the internet attached.

How is this KRKTE calculation made?

252cc/min @3Bar is 290,98cc/min @4Bar.

KRKTE= 50,2624*Vhzyl/Qstat
Vhzyl=0,44525
Qstat= 199,12 N-heptan
KRKTE=0,11239

Acording to TVB - there should be 258cc/min injectors.
With those injectors KRKTE=0,10977.
It's completely different what i do have on ori KRKTE.

Also in attached "injectors-calc-flow-data.pdf" once is't specyfied that those injectors have 252cc/min @3bar and then that it's 189,7n-heptan @3bar. That doesn't fit with the converter, because it's 189,7 g/min petrol.

Any help, much appreciated.
« Last Edit: March 18, 2017, 02:57:44 AM by CQ1 » Logged
KasperH
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« Reply #1 on: March 18, 2017, 03:45:25 AM »
So is your stock FPR 4 bar or 3 bar?
What KRKTE are you trying to calculate? 3? 3.5? 4 bar?
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CQ1
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« Reply #2 on: March 18, 2017, 04:01:03 AM »
Stock FPR is 4 Bar.
I'm trying to underestand how is KRKTE calculated in ori bin, because every each time i do calculation got something different.
Why KVB value is 298,59?

Are those ori injectors - 0280156065:
252cc/min, 258cc/min, or 277cc/min @ 3bar?

Further i want to swap injectors on BEX 028156061 and work on 4 Bar FPR.
« Last Edit: March 18, 2017, 04:09:46 AM by CQ1 » Logged
TijnCU
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flying brick
« Reply #3 on: March 18, 2017, 07:46:11 AM »
Well, you kind of answered your own question in the opening post...
Quote from: CQ1 on March 18, 2017, 02:43:32 AM
Stock bin KRKTE - 0,10478 - factor offset 0,000111
Stock bin KVB - 298,59
...
252cc/min @3Bar is 290,98cc/min @4Bar.
KVB is very much in the direction of your calculated fuel pressure for 4 bar. If I use my calculator for KRKTE value, I end up around 311cc/min, but 258cc/min @ 4 bar = 297.9cc/min (calculated).
« Last Edit: March 18, 2017, 07:55:02 AM by TijnCU » Logged
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CQ1
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« Reply #4 on: March 18, 2017, 08:59:18 AM »
Quote from: TijnCU on March 18, 2017, 07:46:11 AM
Well, you kind of answered your own question in the opening post...KVB is very much in the direction of your calculated fuel pressure for 4 bar. If I use my calculator for KRKTE value, I end up around 311cc/min, but 258cc/min @ 4 bar = 297.9cc/min (calculated).

Ok, so why is it KRKTE then - 0,10478 and not 0,10982?
This KRKTE fits more to 320cc/min @4Bar. (0,10218), or as You mentioned 311cc/min.
Are there any other variables which i'm missing calculating this?
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aef
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« Reply #5 on: March 19, 2017, 09:45:00 AM »
Numbers are not that important. dont destroy your brain by too much thinking about stock values.
Have a look at your fuel trims in block 32 and try to change krkte in small steps to keep the trims low.

Fuel trims can fix human krkte calculation errors by 25%  Cheesy
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CQ1
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« Reply #6 on: March 20, 2017, 12:29:05 AM »
Quote from: aef on March 19, 2017, 09:45:00 AM
Numbers are not that important. dont destroy your brain by too much thinking about stock values.
Have a look at your fuel trims in block 32 and try to change krkte in small steps to keep the trims low.

Fuel trims can fix human krkte calculation errors by 25%  Cheesy

Thank You. That's useful info. I got not so much experience with this, that's why i've been trying to calculate it good before start.
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TijnCU
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flying brick
« Reply #7 on: March 20, 2017, 12:45:50 AM »
For whatever you know, the injectors might be flowing ~310cc in reality. You did not test them on a flow-testbench right..
But yeah, calculate first and then test in real world conditions. You can finetune from your LTFT %  Smiley
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CQ1
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« Reply #8 on: March 20, 2017, 08:24:01 AM »
Quote from: TijnCU on March 20, 2017, 12:45:50 AM
For whatever you know, the injectors might be flowing ~310cc in reality. You did not test them on a flow-testbench right..
But yeah, calculate first and then test in real world conditions. You can finetune from your LTFT %  Smiley

Thanks  Smiley
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