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Title: ME7 and displacement of the engine growth? Post by: a200tq on July 07, 2011, 08:32:17 AM 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? Title: Re: ME7 and displacement of the engine growth? Post by: Rick on July 10, 2011, 01:37:30 PM You need to look at function BGSRM
Title: Re: ME7 and displacement of the engine growth? Post by: Rick on July 10, 2011, 01:43:10 PM Also, MLMAX should be increased by the factor you have increased the engine capacity by.
Rick Title: Re: ME7 and displacement of the engine growth? Post by: Jason on July 10, 2011, 09:16:11 PM 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? Title: Re: ME7 and displacement of the engine growth? Post by: Rick on July 11, 2011, 12:09:44 AM Have a look at the MLMAX value on for the RS4 which has a higher rev limit.
Title: Re: ME7 and displacement of the engine growth? Post by: a200tq on July 16, 2011, 02:46:56 PM 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? Title: Re: ME7 and displacement of the engine growth? Post by: Rick on July 16, 2011, 04:00:56 PM and MLMAX
Title: Re: ME7 and displacement of the engine growth? Post by: a200tq on July 16, 2011, 11:17:58 PM Title: Re: ME7 and displacement of the engine growth? Post by: a200tq on July 18, 2011, 08:23:19 AM 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.
Title: Re: ME7 and displacement of the engine growth? Post by: Rick on July 18, 2011, 11:15:05 AM It relates airflow to load.
Title: Re: ME7 and displacement of the engine growth? Post by: nyet on July 18, 2011, 01:05:35 PM 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? Title: Re: ME7 and displacement of the engine growth? Post by: Rick on July 18, 2011, 01:37:42 PM It won't cap load, but I believe that calculated load is less as MLMAX is increased.
Rick Title: Re: ME7 and displacement of the engine growth? Post by: gremlin on July 18, 2011, 04:36:13 PM 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... |