itb mode first setup

Tuning concepts, methods, tips etc.

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kaeman
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itb mode first setup

Post by kaeman »

I am changing over from speed density mode to itb mode, when I filled out the info on the itb load tps switch points curve using data from many data logs as I filled in the points it changed the curve in the itb load at tps switch points curve, in the manual ms3 setting up section 3.4.5.1 it talks about that curve being set at 50% all the way across the curve, my curve never had the 50% values in it and they changed as I loaded switch points into the itb load tps switch points to the values in the attached tune file.

also when I was running the engine I noticed that the ve tables had the same load settings values(the Y axis) as my speed density map values is that normal?

when running speed density I have very good throttle response, with the itb tune loaded it just boggs down when I make a quick throttle change.
itb mode single ve table.msq
2015-03-05_itb mode single ve table_modified.msl
64 el camino, 383 SBC, 11.7 to1 CR, accufab tb/rhs intake, 44lb injectors, trick flow heads, xr292r solid roller cam, belt drive camshaft, dry sump oil system, 2400 stall, turbo 350, spooled 9 inch, strange axles, 3.89 gears, dual wideband, full sequential fuel/cop, MS3x using 1.4.1 code.
elutionsdesign
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Re: itb mode first setup

Post by elutionsdesign »

Yes, that's normal, it's now ITB load instead of MAP load but load is load. As far as the quick throttle changes it just needs a bunch more fuel, raise your accel amounts and raise the time as well.
Graduate of EFI University.

I build, repair, install and tune Megasquirt systems in North Dakota and beyond!
kaeman
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Joined: Sun Nov 06, 2005 12:31 am
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Re: itb mode first setup

Post by kaeman »

I have been experiencing a rich miss fire in the low rpm high kpa values in the ve table, the more fuel I have been pulling out the better the acceleration and engine response in this area under the speed density mode, this table was my speed density mode dual tables combined into a single table in the itb mode. I just don't understand why the load axis doesn't reflect 0 to 100 percent rather than the kpa bins from the SD mode. I am missing something in my understanding of the itb mode tables and setup. when I changed back to speed density mode the engine has better response and I understand that that should be related to the amount of time used tuning the ve tables, but I guess I just didn't expect the load values to remain the same as the speed density values. I will upload the tune and a data log taken few minutes after the itb mode was changed back to SD.
64 el camino, 383 SBC, 11.7 to1 CR, accufab tb/rhs intake, 44lb injectors, trick flow heads, xr292r solid roller cam, belt drive camshaft, dry sump oil system, 2400 stall, turbo 350, spooled 9 inch, strange axles, 3.89 gears, dual wideband, full sequential fuel/cop, MS3x using 1.4.1 code.
kaeman
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Joined: Sun Nov 06, 2005 12:31 am
Location: NORTHERN CALIFORNIA

Re: itb mode first setup

Post by kaeman »

Here is the sd tune and datalog
first trigger wheel tune.msq
2015-03-05_sd mode first trigger wheel tune_modified.msl
64 el camino, 383 SBC, 11.7 to1 CR, accufab tb/rhs intake, 44lb injectors, trick flow heads, xr292r solid roller cam, belt drive camshaft, dry sump oil system, 2400 stall, turbo 350, spooled 9 inch, strange axles, 3.89 gears, dual wideband, full sequential fuel/cop, MS3x using 1.4.1 code.
muythaibxr
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Re: itb mode first setup

Post by muythaibxr »

When you change to ITB mode it changes the shape of your VE table. You have to retune it completely. ITB mode is a hybrid of SD and AN. Once you get the threshold curve and VE right it should work better than SD.
Megasquirt is not for use on pollution controlled vehicles. Any advice I give is for off road use only.
kaeman
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Joined: Sun Nov 06, 2005 12:31 am
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Re: itb mode first setup

Post by kaeman »

should the itb load values be the same as the sd load values or do I need to rebin the table and then start the tuning process from scratch, or should I stick with the sd load values in the left hand column.
should the itb load mode left hand column have a 0 to 100 load range rather than the 40 to 105 range for the speed density.
64 el camino, 383 SBC, 11.7 to1 CR, accufab tb/rhs intake, 44lb injectors, trick flow heads, xr292r solid roller cam, belt drive camshaft, dry sump oil system, 2400 stall, turbo 350, spooled 9 inch, strange axles, 3.89 gears, dual wideband, full sequential fuel/cop, MS3x using 1.4.1 code.
kaeman
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Joined: Sun Nov 06, 2005 12:31 am
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Re: itb mode first setup

Post by kaeman »

I would like someone to look this msq over, I am going to try it in my vehicle as an alternative to the itb mode that has the ve table bins using the speed density load values. I have changed the itb load values column to go from 0 to 100. rather than the 40 to 105 kpa that speed density was using.
itb single table new defaults axis..msq
64 el camino, 383 SBC, 11.7 to1 CR, accufab tb/rhs intake, 44lb injectors, trick flow heads, xr292r solid roller cam, belt drive camshaft, dry sump oil system, 2400 stall, turbo 350, spooled 9 inch, strange axles, 3.89 gears, dual wideband, full sequential fuel/cop, MS3x using 1.4.1 code.
grom_e30
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Re: itb mode first setup

Post by grom_e30 »

do you really need you load to go down that low? iv only used itb on my motorbike it idles about 80kpa and that works out to be about 40% itb load for me at idle even if i am engine braking really hard i only dip down to 20% load, to me your load scale looks more like its for a alpha-n setup.
1990 bmw 320i daily driver with m20b25 ms3 sequential fuel, 380cc injectors, d585 coil near plug, home made cam sync, launch control, fan control, vss, homebrew egt logging what's next????
kaeman
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Re: itb mode first setup

Post by kaeman »

Thanks, I was thinging that the load column should be different that the speed density load column, but your saying it should more closely resemble the speed density setting that I have running with for all these years. I will give it a try and post new logs and msq's.
64 el camino, 383 SBC, 11.7 to1 CR, accufab tb/rhs intake, 44lb injectors, trick flow heads, xr292r solid roller cam, belt drive camshaft, dry sump oil system, 2400 stall, turbo 350, spooled 9 inch, strange axles, 3.89 gears, dual wideband, full sequential fuel/cop, MS3x using 1.4.1 code.
muythaibxr
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Re: itb mode first setup

Post by muythaibxr »

Mine goes down to 20. It really just depends on the lowest value you see when driving with your settings.
Megasquirt is not for use on pollution controlled vehicles. Any advice I give is for off road use only.
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