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Thread: Question about Torque Inverse Calculator

  1. #21
    Advanced Tuner
    Join Date
    Sep 2018
    Posts
    213
    Quote Originally Posted by mattlinke View Post
    lol. Same boat.

    Im tuning a Boss 302 with a Kenne Bell 3.6 and mono blade 168 on it. I finally got the surge/oscillation mostly worked out and other than a few minor things I hope to iron out this season, it drives pretty decent for the most part. The TQ error however is off the charts in some areas. However while its having a fit about tq error it still drives fine.

    I tried 99 different methods to tune the TB airflow table and the Tq tables based on the 99 different methods ive seen on these forums. some worked sorta and others didnt. Id get to a point where it would start getting worse using the same methods, or TQ error would reduce but it would still drive like garbage.

    I gave up and started winging it. I literally just kept moving the tq tables up or down and adjusting DD (mostly to soften the transition to boost when the bypass would close because its kinda harsh) until the car drove smooth and would accelerate smooth with a steady throttle. I did reference a few other blower tunes to get a general idea of where i should be, but in large part the tq tables i use in that car are just ones I made up for now and it drives pretty great.
    You're exactly right. Trying one method starts to get results but than goes haywire the next adjustment. Heck just last night I had it really smooth made one adjustment and now throttle opens way to far when trying to accelerate at highway speeds. Had it open far enough at 1800 rpms without it downshifting or pulling timing that I'm lucky it didn't knock....
    There has to be some calculation were missing...… I'm sure Ford is basing torque numbers on air consumed and timing correct? I wouldn't think Ford's ECU stores what combo equates to how much torque. Makes me wonder if they just interlope current timing from MBT is spit out a torque number. For example if you put in torque table 50 foot pounds at 700 RPM @ .25 load than the computer looks at current air consumed and current timing. Assuming air flow is spot on it looks at how far off timing is from MBT and calculates a slightly lower torque number.... I know there is way more to it but trying to think in simple terms.....

    I'm trying to put together a spreadsheet that does the following.
    Border line spark from tune
    MBT from tune
    Torque table from tune
    Inverse torque from tune
    Driver demand table from tune
    Logged airflow in G/S
    Logged actual spark
    Logged pedal A/D on Inverse table and torque table
    Logged throttle angle on torque table
    Logged air load on inverse table

    Use airflow to calculate torque but use math to calculate what torque should be based on logged spark. So if spark is at MBT than torque is true. If it's below than find how much lower and figure what it would be. Then have sheet somehow reference driver demand table to torque table (rearrange or whatever) so that it's easier to follow driver demand to torque table. Adjust driver demand to be on the lower side of the torque table (or higher still unsure of this) Input new torque numbers in tune and drive in the same conditions. Paste logged values back into the spreadsheet. Now compare throttle opening to the log before. Also, have the spreadsheet look at the airload to torque and calculate any errors...

    I'm just shooting from the hip on this based off of what makes sense to me but I could very wrong. Also, I probably didn't explain it well enough. Math is not my strong subject and I'm no super user of excel so my whole idea could be impossible...

    Alright.... Back to endlessly chasing my tail on this. Not having it perfect is bothering me LOL

  2. #22
    Advanced Tuner
    Join Date
    Sep 2018
    Posts
    213
    Quote Originally Posted by momotunes View Post
    You're exactly right. Trying one method starts to get results but than goes haywire the next adjustment. Heck just last night I had it really smooth made one adjustment and now throttle opens way to far when trying to accelerate at highway speeds. Had it open far enough at 1800 rpms without it downshifting or pulling timing that I'm lucky it didn't knock....
    There has to be some calculation were missing...? I'm sure Ford is basing torque numbers on air consumed and timing correct? I wouldn't think Ford's ECU stores what combo equates to how much torque. Makes me wonder if they just interlope current timing from MBT is spit out a torque number. For example if you put in torque table 50 foot pounds at 700 RPM @ .25 load than the computer looks at current air consumed and current timing. Assuming air flow is spot on it looks at how far off timing is from MBT and calculates a slightly lower torque number.... I know there is way more to it but trying to think in simple terms.....

    I'm trying to put together a spreadsheet that does the following.
    Border line spark from tune
    MBT from tune
    Torque table from tune
    Inverse torque from tune
    Driver demand table from tune
    Logged airflow in G/S
    Logged actual spark
    Logged pedal A/D on Inverse table and torque table
    Logged throttle angle on torque table
    Logged air load on inverse table

    Use airflow to calculate torque but use math to calculate what torque should be based on logged spark. So if spark is at MBT than torque is true. If it's below than find how much lower and figure what it would be. Then have sheet somehow reference driver demand table to torque table (rearrange or whatever) so that it's easier to follow driver demand to torque table. Adjust driver demand to be on the lower side of the torque table (or higher still unsure of this) Input new torque numbers in tune and drive in the same conditions. Paste logged values back into the spreadsheet. Now compare throttle opening to the log before. Also, have the spreadsheet look at the airload to torque and calculate any errors...

    I'm just shooting from the hip on this based off of what makes sense to me but I could very wrong. Also, I probably didn't explain it well enough. Math is not my strong subject and I'm no super user of excel so my whole idea could be impossible...

    Alright.... Back to endlessly chasing my tail on this. Not having it perfect is bothering me LOL
    I want to add that I know there is way more to it than spark but my thinking is start simple, prove the theory, and if it works bring in things like VCT and such. My guess is there is so many variables that anything available (that I've found) doesn't work as it doesn't account for everything. What people have put together works because their motor had different variables but it doesn't work for us because our conditions are different?

    I forgot where exactly I read it or what post but Ford wanted to be able to increase speed (torque) without always opening throttle. Things like VCT and what not. That's why I'm assuming driver demand maybe goes on the lower end of your torque tables??