VE Spreadsheet
Here is a VE calculator I have been using to fine tune, see what you all think, I'd appreciatte some feedback. It's worked for me, and while I'm not an excel genius, the table has done wonders for my VE table.
http://www.tditechnology.com/VE-Calculator.xls
http://www.tditechnology.com/VE-Calculator.xls
Last edited by 99FormulaWs6; Aug 9, 2005 at 11:44 AM.
I'll give it a shot and let you know.
edit:
now that I've downloaded it, it looks very similar to the spread sheet I used a while back. Nice work! your's is much more a finished product than mine
edit:
now that I've downloaded it, it looks very similar to the spread sheet I used a while back. Nice work! your's is much more a finished product than mine
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Quick question on some of your formulas on the worksheet. I'm brand new to tuning so there's a good chance I'm looking at this incorrectly.
1. On the Calculation Sheet: The formula you're using is LTFT - STFT / 2 to get the %
change on the VE Table. Don't you want LTFT + STFT / 2 ?
2. On the New VE Table Sheet: The formula you're using is Current VE Value - Calculation Sheet Value. Again, don't you want Current VE Value + Calculation Sheet Value?
The problem I've noticed is if you have negative fuel trims. Let me show an example:
Say you have a LTFT value of -10, a STFT value of -5, and a Current VE of 50
Calculation Sheet: LTFT - STFT = % VE Change, (-10) - (-5) = -5
New VE Table Sheet: Current VE - Calc Sheet Value = New VE, (50) - (-5) = 55
The problem I see is that if the car is pulling fuel you want to lower the VE and these calulations end up raising it.
Same values using the 2nd formulas:
Calculation Sheet: LTFT + STFT = % VE Change, (-10) + (-5) = -15
New VE Table Sheet: Current VE + Calc Sheet Value = New VE, (50) + (-15) = 35
Obviously I just pulled these values out of the air, but the calculations are valid (I think). Sorry this is hard to follow, but let me know if I'm on the right track or totally wrong. Thanks!
1. On the Calculation Sheet: The formula you're using is LTFT - STFT / 2 to get the %
change on the VE Table. Don't you want LTFT + STFT / 2 ?
2. On the New VE Table Sheet: The formula you're using is Current VE Value - Calculation Sheet Value. Again, don't you want Current VE Value + Calculation Sheet Value?
The problem I've noticed is if you have negative fuel trims. Let me show an example:
Say you have a LTFT value of -10, a STFT value of -5, and a Current VE of 50
Calculation Sheet: LTFT - STFT = % VE Change, (-10) - (-5) = -5
New VE Table Sheet: Current VE - Calc Sheet Value = New VE, (50) - (-5) = 55
The problem I see is that if the car is pulling fuel you want to lower the VE and these calulations end up raising it.
Same values using the 2nd formulas:
Calculation Sheet: LTFT + STFT = % VE Change, (-10) + (-5) = -15
New VE Table Sheet: Current VE + Calc Sheet Value = New VE, (50) + (-15) = 35
Obviously I just pulled these values out of the air, but the calculations are valid (I think). Sorry this is hard to follow, but let me know if I'm on the right track or totally wrong. Thanks!
Here's a copy of 99FormulaWS6's spreadsheet with the formulas adjusted how I'm thinking they might need to be. Let me know what you guys think. He really did a great job on this spreadsheet. Makes things much simpler.
Lowell, I'm not sure why it would or wouldn't work i'll have to try your copy, and see what it does. Mine worked for me, so
OrangeWs6 it won't work in Edit, because you need a Data logger with the histogram function.
OrangeWs6 it won't work in Edit, because you need a Data logger with the histogram function. Lowell...see if this makes sense. Lowering the VE tables, will lean out the car in that area. Its telling the PCM there is less air there, so there will be less fuel introduced. So in your example if your at a (-) LTFT, then you go from 50 to 55 in the VE you should come less (-) or closer to 0 from your previous reading, which is the goal, or slightly negative. Does this answer your question or help you in anyway? I hope so, cause now I am confused
Originally Posted by CAT3
Lowell...see if this makes sense. Lowering the VE tables, will lean out the car in that area. Its telling the PCM there is less air there, so there will be less fuel introduced. So in your example if your at a (-) LTFT, then you go from 50 to 55 in the VE you should come less (-) or closer to 0 from your previous reading, which is the goal, or slightly negative. Does this answer your question or help you in anyway? I hope so, cause now I am confused 

Will this spreedsheet also work on a 98 C5? I am in the process on tuning the STFT first, is that the right way to do it? I was told by doing the STFT first, the LTFT should fall in line?
Thanks,
Jason
Thanks,
Jason
Blown, Your STFT's with time will zero out, reset your Fuel trims and watch your STFTs in your histogram they will gradually fall. Get your STFT's within +(-)5 then use the sheet, and yes it will work for your car.





