spark adder question for you p59 3bar flex fuel guys
#1
Thread Starter
Joined: Nov 2013
Posts: 6,332
Likes: 527
From: Portlandia
spark adder question for you p59 3bar flex fuel guys
are you manipulating your spark directly in the main spark advance table and zeroing the flex fuel spark adder table? (this is how denmah is doing his)
or are you leaving the main set for gasoline and manipulating your spark in the FF table? (the way i'd like to do it, since im not full time e85)
on a similar note he showed me a dual VE table OS
one with normal resolution for <100kPa and then a second for >100kPa
is anyone using that?
I find the reduced resolution 30-300kPa works pretty good if you stay on the rich side and let the narrow bands do idle fueling.
I guess my concern stems from how I was taught to tune PE/BE
I was told BE fuel is really laggy so to zero it and use PE for all my "WOT" fueling.
thoughts, concerns, arguments? i'm all ears.
or are you leaving the main set for gasoline and manipulating your spark in the FF table? (the way i'd like to do it, since im not full time e85)
on a similar note he showed me a dual VE table OS
one with normal resolution for <100kPa and then a second for >100kPa
is anyone using that?
I find the reduced resolution 30-300kPa works pretty good if you stay on the rich side and let the narrow bands do idle fueling.
I guess my concern stems from how I was taught to tune PE/BE
I was told BE fuel is really laggy so to zero it and use PE for all my "WOT" fueling.
thoughts, concerns, arguments? i'm all ears.
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Skeetrat (02-18-2020)
#3
This is an E40 computer with a GM Flex sensor. I leave the High Octane table to run on 93. I use the flex timing table to add for E85. In the higher rpm (wot) area, I add one half of the timing that I want, and add the other half thru the AFR correction table. That is in case the sensor fails at wot, it will at least pull 1/2 of the timing adder. The AFR correction table and the Flex timing table add together. I have added 6 degrees total at wot, 3 degrees in the FF table and 3 degrees in the AFR table. I use the dual VE setup--Primary is to 105kpa and the Boost table is 105 to 255kpa (2 bar sd). I'm not sure what you mean by BE fuel being laggy??
Last edited by dw456post; 03-21-2018 at 08:17 AM.
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Skeetrat (02-18-2020)
#4
Thread Starter
Joined: Nov 2013
Posts: 6,332
Likes: 527
From: Portlandia
I really like that approach, I will try that.
As far as BE being laggy, I was told the BE tables have a lag time and most people put all their fuel adders numbers in PE.
I'm on mobile now but I'll post screen shots tonight that might help clarify.
As far as BE being laggy, I was told the BE tables have a lag time and most people put all their fuel adders numbers in PE.
I'm on mobile now but I'll post screen shots tonight that might help clarify.
#5
Anybody who uses the boost enrichment table in the HPT custom OS in a Gen3 application definitely hasn't been doing this long and seen what happens. The BE routines run in a much slower ring and have a pretty serious lag to them, use PE only and just leave BE as 1.00 across the board.
As far as adding timing for ethanol use the built in tables that are intended to be used with it and you will have the best results as GM intended.
As far as adding timing for ethanol use the built in tables that are intended to be used with it and you will have the best results as GM intended.
#6
Anybody who uses the boost enrichment table in the HPT custom OS in a Gen3 application definitely hasn't been doing this long and seen what happens. The BE routines run in a much slower ring and have a pretty serious lag to them, use PE only and just leave BE as 1.00 across the board.
As far as adding timing for ethanol use the built in tables that are intended to be used with it and you will have the best results as GM intended.
As far as adding timing for ethanol use the built in tables that are intended to be used with it and you will have the best results as GM intended.
#7
Anybody who uses the boost enrichment table in the HPT custom OS in a Gen3 application definitely hasn't been doing this long and seen what happens. The BE routines run in a much slower ring and have a pretty serious lag to them, use PE only and just leave BE as 1.00 across the board.
As far as adding timing for ethanol use the built in tables that are intended to be used with it and you will have the best results as GM intended.
As far as adding timing for ethanol use the built in tables that are intended to be used with it and you will have the best results as GM intended.
Thanks
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#8
I'm self taught other than plenty of advice from members here so I don't know what accepted practices are, but I have both my PE and BE set the same. I also have my open loop EQ ratio ramping up from stoich starting at 95 kpa and at 100 kpa it's half way between stoich and my pe/be ratio. I never get a lean spike and it seems to work well for me.
#9
#13
are you manipulating your spark directly in the main spark advance table and zeroing the flex fuel spark adder table? (this is how denmah is doing his) completely defeats the purpose to do it like this. You set the main spark table for gasoline and "modify" the table, in this case adding to the timing, by using the flex fuel timing table or the alcohol table on the timing modifier afr correction.
or are you leaving the main set for gasoline and manipulating your spark in the FF table? (the way i'd like to do it, since im not full time e85)
on a similar note he showed me a dual VE table OS
one with normal resolution for <100kPa and then a second for >100kPa
is anyone using that? no need to do this TBH, itll drive damn good with even a low resolution under part throttle conditions. Ive done ALOT, you will never get it perfect but it will be really really good. If you are having issues, you need to look into something else, i.e. mechanical components or wiring.
I find the reduced resolution 30-300kPa works pretty good if you stay on the rich side and let the narrow bands do idle fueling.
I guess my concern stems from how I was taught to tune PE/BE
I was told BE fuel is really laggy so to zero it and use PE for all my "WOT" fueling. straight up false. Half of the use of a custom OS is to have fuel enrichment based on KPA. Not laggy one bit. I've done more turbo builds using BE than I can count as you can see in my facebook( i think i have you there doug?) or website.
thoughts, concerns, arguments? i'm all ears.
or are you leaving the main set for gasoline and manipulating your spark in the FF table? (the way i'd like to do it, since im not full time e85)
on a similar note he showed me a dual VE table OS
one with normal resolution for <100kPa and then a second for >100kPa
is anyone using that? no need to do this TBH, itll drive damn good with even a low resolution under part throttle conditions. Ive done ALOT, you will never get it perfect but it will be really really good. If you are having issues, you need to look into something else, i.e. mechanical components or wiring.
I find the reduced resolution 30-300kPa works pretty good if you stay on the rich side and let the narrow bands do idle fueling.
I guess my concern stems from how I was taught to tune PE/BE
I was told BE fuel is really laggy so to zero it and use PE for all my "WOT" fueling. straight up false. Half of the use of a custom OS is to have fuel enrichment based on KPA. Not laggy one bit. I've done more turbo builds using BE than I can count as you can see in my facebook( i think i have you there doug?) or website.
thoughts, concerns, arguments? i'm all ears.