Primary vs. Secondary VE
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Primary vs. Secondary VE Just want to completely understand this before I go any further. Is the primary VE table the only one that should be edited when the MAF is used? The secondary should be edited when the car is in SD mode and the primary shouldn't be touched?? I may be completely wrong but definitely want to figure it out. Thanks once again!
With a car running a stock operating system ('98-'00), the PCM will reference the secondary VE and low octane timing tables. While the MAF is active, it will use the primary VE and the high/low octane timing tables (depending on where the octane scaler is, which reacts to KR).
Ideally, once you tune the car in SD, you want to copy over the secondary VE to the primary and hand smooth in the x5kPa cells. Then, re-enable your MAF and tune the MAF table. You shouldn't have to adjust the VE once it has been tuned and the MAF has been re-enabled. But if you must, then yes the primary one is the one to go for. Also, if you do change the primary VE, you should copy any changes to the x0kPa cells to the secondary VE to keep things consistent. Just make sure you save a copy of the last SD tune you did so you always have a point to go back to if things get too messed up.
Ideally, once you tune the car in SD, you want to copy over the secondary VE to the primary and hand smooth in the x5kPa cells. Then, re-enable your MAF and tune the MAF table. You shouldn't have to adjust the VE once it has been tuned and the MAF has been re-enabled. But if you must, then yes the primary one is the one to go for. Also, if you do change the primary VE, you should copy any changes to the x0kPa cells to the secondary VE to keep things consistent. Just make sure you save a copy of the last SD tune you did so you always have a point to go back to if things get too messed up.
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I'm curious as to why the Secondary VE table does not have all the numbers that the Primary does. So when you are editing the Secondary what do you do about the missing numbers? For example, Primary has 15, 20, 25, 30, 35, etc. Secondary has 20, 30, 40, 50, 60, etc. 
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Originally Posted by JimMueller
I apply the changes to the primary table, then copy the matching rows to the secondary.
The secondary VE is just a 'blurrier' version of the primary. As long as the 10, 20, 30.....110 rows match, that's the best you can do. The 15, 25, 35....105 rows are something you'll have to guess-timate, hand smooth, etc. That's all the PCM is doing in SD mode. Instead of working with cells 5kPa wide, it's working with cells 10kPa wide in SD.
Yeah, basically the primary is fine resolution and the secondary is coarse resolution. I don't follow why folks are choosing to manually interpolate the x5 rows. I haven't used EFILive, but I assume they have a feature similar to HPT's histograms which will map out the entire primary VE table. Seems like the long way around to map the secondary and guess the missing rows in the primary.
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