a200tq
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« on: July 07, 2011, 08:32:17 AM »
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Hello!
So, there is interesting project. 3.0 engine crankshaft in 2.7tt block with custom pistons=3.0tt. But all other is totally stock-heads, cams, manifolds, turbos etc. On stock chip, of course, requested load is 10-12% lower then actual (114 group of vag-com). In some regimes, this lead to 17965 fault-positive deviation. Yes, in this situation, i can just rise up KFMLDMX, but i dont think that this is good solution.
So-how can i tell to ME7, that now displacement about 10% more, for adequate loads calculate? I dont think, that only KRKTE correction is enough... In what section information about displacement stored?
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Rick
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« Reply #1 on: July 10, 2011, 01:37:30 PM »
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You need to look at function BGSRM
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Rick
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« Reply #2 on: July 10, 2011, 01:43:10 PM »
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Also, MLMAX should be increased by the factor you have increased the engine capacity by.
Rick
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Jason
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Breaks everything!
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« Reply #3 on: July 10, 2011, 09:16:11 PM »
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If you are planning on spinning it above 6800 don't you need to increase MLMAX based on displacement AND max RPM? I noticed this is set at 750kg/hr in the stock m box, and was playing around with numbers:
Assuming air @ STP = 1.25g/l
2700cc = 3.375g/rev
6800rpm * 3.375g / 2 (it's a 4-stroke) = 11475g/min
11475g/min * 60 min = 688500g/hr
Result @ 100% VE = 688.5kg/hr (~7500rpm @ 2.7l = 750kg/hr)
3000cc = 3.75g/revolution
6800rpm * 3.75 / 2 (it's a 4-stroke) = 12750g/min
12750g/min * 60 min = 765000g/hr
Result @ 100% VE = 765kg/hr
3000cc = 3.75g/revolution
8500rpm * 3.75 / 2 (it's a 4-stroke) = 15937g/min
15937g/min * 60 min = 956250/hr
Result @ 100% VE = 956.25kg/hr
Thoughts?
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Rick
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« Reply #4 on: July 11, 2011, 12:09:44 AM »
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Have a look at the MLMAX value on for the RS4 which has a higher rev limit.
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a200tq
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« Reply #5 on: July 16, 2011, 02:46:56 PM »
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So, i am digging in BGSRM, and i am found, that main variable that include engine displacement, is KISRM.
KISRM=zkorr/((Vs/Vh)*z), where zkorr=0.95 at 6 cyl, z=6 cyl, Vh-total engine displacement, Vs-intake manifold volume (if i am understand right).
I am looking in 551G csv file for AGB 27tt s4 engine. KISRM=0,122513. So, Vs/Vh=1,2924.
Old displacement is 2671 new is 2976, this is 1,12 greater. Thus, new Vs/Vh will be 1,1539 and new KISRM will be near 0,13721.
Is it correct? And more important question-is it enough just kisrm correction, for adequate load calculation with new displacement, or i am miss something?
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Rick
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« Reply #6 on: July 16, 2011, 04:00:56 PM »
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and MLMAX
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a200tq
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« Reply #7 on: July 16, 2011, 11:17:58 PM »
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and MLMAX
Rick thank you for you help! |
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a200tq
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« Reply #8 on: July 18, 2011, 08:23:19 AM »
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Some lack of understanding about MLMAX. In functionrahmen, if i am understand right, MLMAX-peak, maximum airflow. In s4-G box this is 800 kg/h, in RS4 F box 1000 kg/h. But even stock, no chipped rs4 flow about 300+ g/s (1080 kg/h) at redline. In chipped, it sometimes more then 350-360 g/s. On chipped s-cars, airflow is about 240-250+ g/s (900 kg/h) at redline. No one correct MLMAX during chipping, and all work without problems, throttle cut, DTCs etc. So-what is the meaning of the MLMAX? I dont understand.
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Rick
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« Reply #9 on: July 18, 2011, 11:15:05 AM »
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It relates airflow to load.
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nyet
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« Reply #10 on: July 18, 2011, 01:05:35 PM »
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It relates airflow to load.
Meaning it won't cap g/sec, but it will cap the load calc so no values bigger than MLMAX are used to calc load? |
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ME7.1 tuning guideECUx PlotME7Sum checksumTrim heatmap toolPlease do not ask me for tunes. I'm here to help people make their own. Do not PM me technical questions! Please, ask all questions on the forums! Doing so will ensure the next person with the same issue gets the opportunity to learn from your ex
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Rick
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« Reply #11 on: July 18, 2011, 01:37:42 PM »
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It won't cap load, but I believe that calculated load is less as MLMAX is increased.
Rick
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gremlin
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« Reply #12 on: July 18, 2011, 04:36:13 PM »
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No one correct MLMAX during chipping, and all work without problems, throttle cut, DTCs etc. So-what is the meaning of the MLMAX? I dont understand.
MLMAX is used only for calculation of almost "dummy" parameter CLV. SAE J1979 request CLV (calc load value 0...100%) as "must have" output data for Scantools. The "dummy" idea CLV is to show current %% of max engine load assuming that max load is achieved at max airflow. And nobody correct MLMAX because it isn't affected on engine operation at all... |
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