As requested by VL400, here is a question regarding $12P. Given that all engines are imprecise devices, what value is VE learn. the likelyhood that a VE value "learned" by the ecu will be foreven correct is close to zero, it is more likely to be incorrect next time & the ecu will have to relearn a new value. a system where the VE table values are determined by averaging a number of logged samples (TunerPro etc) & the entered into the VE table is surely better.
this view is supported by the lumpy VE table I get from the ecu after it has been running VE learn for a time.
another question, to setup lean cruise i assume that using a wideband o2 sensor to get actual exhaust mixture readinds is the only practical method.
Mag's OSE 12P Thread
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Holden202T
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Re: OSE 12P
you shouldn't have to do anything with ve learn enabled ?!?!?!
as far as it being better or worse than logging and changing it yourself, i reckon ve learn is better, it has to meet alot more criteria before it will change a cell than logging and changing.....
eg. ve learn will only work aslong as its within a 50 rpm radius of the cell intersection ..... and 1.56kpa radius .... those two factors along make it alot more accurate than logging blms in 10kpa and 200/400rpm increments!
at the end of the day its doing the same thing as the blms but its an actual change of the ve cell whereas the blms are an offset that is applied to the ve table and it constantly changes to "trim" the ve numbers to suit different conditions, so if you get the table close with ve learn then blms can do the rest.
and if ve learn has no value then you may aswell just chuck an engine in a car with any old tune and go with that, why bother dyno tuning it ?
yes sure ve learn may not be dead accurate but it sure does a good job of getting your VE table where it should be .... and of course this all relies on the other stuff like coolant offset tables etc being calibrated right, if they are then they should account for different driving conditions and hense the ve table should be right!!
is the lumpy ve table cause the high/low points are the only areas that have been changed ? also look at some stock holden bins, the ve tables aren't all smooth, cause engines need different requirements at different loads/rpms! i get similar results with logging blms and then changing the ve table from that!
if your ve table is accurate without lean cruise, ie. when the afr table commands 14.7 if the ve table is actually giving the engine that then the lean cruise table should be right....
if the engine is rich at a given load point then lean cruise will still lean that point out however it will be richer than the commanded afr ... eg. 14.7 + 1.5 afr for lean cruise = 16.2 .... if the wideband is showing 14.1 before lean cruise is enabled then it will effectively be about 15.6 .... still lean but just not quite what it should be.
i would also not recommend using lean cruise until you are happy you have your ve table fairly right to 14.7 first .... also if you feel a jerk/flat spot when lean cruise is cutting in/out then its too lean.
as far as it being better or worse than logging and changing it yourself, i reckon ve learn is better, it has to meet alot more criteria before it will change a cell than logging and changing.....
eg. ve learn will only work aslong as its within a 50 rpm radius of the cell intersection ..... and 1.56kpa radius .... those two factors along make it alot more accurate than logging blms in 10kpa and 200/400rpm increments!
at the end of the day its doing the same thing as the blms but its an actual change of the ve cell whereas the blms are an offset that is applied to the ve table and it constantly changes to "trim" the ve numbers to suit different conditions, so if you get the table close with ve learn then blms can do the rest.
and if ve learn has no value then you may aswell just chuck an engine in a car with any old tune and go with that, why bother dyno tuning it ?
yes sure ve learn may not be dead accurate but it sure does a good job of getting your VE table where it should be .... and of course this all relies on the other stuff like coolant offset tables etc being calibrated right, if they are then they should account for different driving conditions and hense the ve table should be right!!
is the lumpy ve table cause the high/low points are the only areas that have been changed ? also look at some stock holden bins, the ve tables aren't all smooth, cause engines need different requirements at different loads/rpms! i get similar results with logging blms and then changing the ve table from that!
if your ve table is accurate without lean cruise, ie. when the afr table commands 14.7 if the ve table is actually giving the engine that then the lean cruise table should be right....
if the engine is rich at a given load point then lean cruise will still lean that point out however it will be richer than the commanded afr ... eg. 14.7 + 1.5 afr for lean cruise = 16.2 .... if the wideband is showing 14.1 before lean cruise is enabled then it will effectively be about 15.6 .... still lean but just not quite what it should be.
i would also not recommend using lean cruise until you are happy you have your ve table fairly right to 14.7 first .... also if you feel a jerk/flat spot when lean cruise is cutting in/out then its too lean.
No matter what the question is, the answer is always more horsepower! 
Just starting out? Have a read of the getting started guide
Basic tuning of a delco ECM with $12P thread
Advanced tuning of a delco ECM with $12P thread
Just starting out? Have a read of the getting started guide
Basic tuning of a delco ECM with $12P thread
Advanced tuning of a delco ECM with $12P thread
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VL400
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Re: OSE 12P
VE learn is not the be all and end all, you have to do the hard yards still. It will get it close-ish and then you have to manually tune it. There are also configuration options for VE learn, you can use them to slow the learn process.mag wrote:As requested by VL400, here is a question regarding $12P. Given that all engines are imprecise devices, what value is VE learn. the likelyhood that a VE value "learned" by the ecu will be foreven correct is close to zero, it is more likely to be incorrect next time & the ecu will have to relearn a new value. a system where the VE table values are determined by averaging a number of logged samples (TunerPro etc) & the entered into the VE table is surely better.
this view is supported by the lumpy VE table I get from the ecu after it has been running VE learn for a time.
another question, to setup lean cruise i assume that using a wideband o2 sensor to get actual exhaust mixture readinds is the only practical method.
Providing the VE is correct (or fairly close) the commanded AFR will also be correct when in lean cruise, so whatever you command you get. Get the VE right before using lean cruise.mag wrote:another question, to setup lean cruise i assume that using a wideband o2 sensor to get actual exhaust mixture readinds is the only practical method.
Re: OSE 12P
Have a $12P v6 cal based on the BLCD & AFTY ve & ignition tables from my vn, if anyone interested. its the one i have been running. all pretty basic, just trying to get a smooth idle & clean take-off. at present it runs well, no stalling when stopping, accepts a/c & p/s loads ok but with all the wet weather i have not be able to test the most recent changes to get a good hot start idle. think problem might have been idle ve values, have changed them to match those from the AFTY bin.
I'll post it once i am happy with the hot start idle.
I'll post it once i am happy with the hot start idle.
Re: OSE 12P
Been playing with my DIY 2 bar map, now calibrated against original GM 1 bar, & have noticed that when using $12P 2 bar bin that "target AFR" dips to 13 when MAP senses a large load & then returns to 14.7. this is what i would have expected, richer mixture for bigger load & the equivalent of an accelerator pump, but when i replay a log of the 1 bar bin I seen no such pattern. the "target AFR" remains pretty much constant at 14.7. only the biggest of load changes causes a small dip in the "target AFR".
the 2 bar map values, both scaled & actual, track together ie no response delays & mirror the values from the 1 bar map.
the 2 bar map values, both scaled & actual, track together ie no response delays & mirror the values from the 1 bar map.
Re: OSE 12P
Was hoping for comment on my observation regarding AFR changes with load. If AFR change with engine load change is normal ie accelerator pump action, why the big difference between 1 & 2 bar bin response.
Re: OSE 12P
What do you mean by DIY 2 BAR MAP SENSOR.How did you make your own 2 bar sensor. 
Re: OSE 12P
Yes VN5000, used a motorola sensor & added the output interface get 0-5 volts for 0-200kPA. Car drives with my diy sensor & 2 bar $12P bin but have issues with a bad stumble off idle when first started (hot or cold) that disappears after 1/2 minutes. also engine a bit flat dowm low compared to 1 bar bin & sensor.
Hence my question regarding AFR change when engine load changes. Wondering why 2 bar setup should be so different to 1 bar, as this is the only difference I can see.
Hence my question regarding AFR change when engine load changes. Wondering why 2 bar setup should be so different to 1 bar, as this is the only difference I can see.
Re: OSE 12P
What is this motorolla map sensor off. Is it a 1 or 2 bar sensor and what is the output interface .?
Does it read around 2.5v at 100 kpa and 5.0 v at 200 kpa.
If so the ecu will read 100 kpa at 5v with 1bar bin and 100 kpa on the 2 bar bin will be read at around 2.5v so it would run at diff a/f depending in what youve set them at , possibly after .5 min the blm and int kick in and correct fuel mix if a/f ratio set at 14.7 .
Why are you running a 2 bar sensor on normally aspirated motor any way ,you are loosing half the actuall map sensor resolution as a 2 bar sensor never reads over around 2.5 v on a n/a motor
Does it read around 2.5v at 100 kpa and 5.0 v at 200 kpa.
If so the ecu will read 100 kpa at 5v with 1bar bin and 100 kpa on the 2 bar bin will be read at around 2.5v so it would run at diff a/f depending in what youve set them at , possibly after .5 min the blm and int kick in and correct fuel mix if a/f ratio set at 14.7 .
Why are you running a 2 bar sensor on normally aspirated motor any way ,you are loosing half the actuall map sensor resolution as a 2 bar sensor never reads over around 2.5 v on a n/a motor
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Holden202T
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Re: OSE 12P
i think he plans to put a blower on this motor at some stage.
No matter what the question is, the answer is always more horsepower!
Just starting out? Have a read of the getting started guide
Basic tuning of a delco ECM with $12P thread
Advanced tuning of a delco ECM with $12P thread
Just starting out? Have a read of the getting started guide
Basic tuning of a delco ECM with $12P thread
Advanced tuning of a delco ECM with $12P thread