Page 1 of 7 123 ... LastLast
Results 1 to 10 of 66

Thread: EFI RWHP and EFI RWTQ

  1. #1
    Lifetime Member
    Join Date
    Jun 2003
    Posts
    205

    Default EFI RWHP and EFI RWTQ

    Hey Guys
    A LOOOOONG time ago I had enhanced the HP calc pid in this thread
    http://forum.efilive.com/showthread.php?t=3&page=5
    Calculating Instantaneous Net Power

    I am on a local musclecar forum ( http://www.musclecar-evolution.com/forums ) and thanks to one of the guys during a heated HP thread the equasion was posted for torque. Having that I figured why not create a calc pid for that also. ( thx skeeveman for the equasion info )

    I get so many people asking about a HP number and where it came from, and I only use EFI, no reason to hit a dyno, I have this and a wb02 ( lc1 from greenlight motorsports ) why waste the money to get a number from a dyno when I have everything here.

    so on with the new pid.
    The formula given was for torque based on hp numbers below
    ====================
    hp=(tq*rpm)/5252
    hp*5252=tq*rpm
    (hp*5252)/rpm = tq
    ====================


    What I had used for HP in my calc back then:

    OLD
    *CLC-00-989
    hp 0.0 400.0 .0 "(((3554+({GM.FUELREM}*6.350)+185)*{SAE.VSS.mp h})* dx({SAE.VSS.mph},6))/8226.63"

    CALC.SSHPTRUE6 F60A CLC-00-989 "kW,hp" Performance "SS TRUE HP 06"

    But to make it more accurate name: "(car) EFI RWHP Smoothing Factor 6"
    Something that can be added, instead of 3554 ( using the customer vehicle weigh pid ), the 185 is the driver weight
    NEW
    *CLC-00-989
    hp 0.0 400.0 .0 "(((3554+({GM.FUELREM}*6.350)+185)*{SAE.VSS.mp h})* dx({SAE.VSS.mph},6))/8226.63"

    CALC.SSEFIRWHP6 F60A CLC-00-989 "kW,hp" Performance "SS EFI RWHP Smoothing Factor 6"

    There are the smoothing factors for 2, 6, 12 depending just like a dyno on the change in polling.

    Now for Torque: Change the 9XX to your favorite pid #.

    *CLC-00-9XX
    hp 0.0 400.0 .0 "(CALC.SSEFIRWHP6*5252)/SAE.RPM"

    CALC.SSEFIRWTQ6 F60A CLC-00-9XX "kW,hp" Performance "EFI RWTQ Smoothing Factor 6"

    In the end you have a nice rolling dyno giving you EFI HP and TQ numbers.

    Its the dawn of a new day, forget Dyno RWHP and RWTQ
    Go with EFI RWHP and RWTQ
    Last edited by dbaxter_ss; September 12th, 2007 at 02:48 PM.

  2. #2
    Lifetime Member
    Join Date
    Jan 2007
    Posts
    293

    Default

    Wow! This is really cool.

    I did some digging and found something:
    http://ohe.cat.com/cda/files/287140/7/LEGT5364.pdf

    This PDF put out by CAT has some estimates of rolling resistance and HP required to maintain speed for certain speeds. With the VSS derived PID I think it would be super easy to make the HP calc even more accurate!!

    I tried to find you the equation that takes CDA of our cars and translates it into HP lost but couldn't find it for you. Sorry. :( All I know is HP lost would be the square of speed.

  3. #3
    Lifetime Member Chalky's Avatar
    Join Date
    Sep 2003
    Posts
    616

    Default

    Where do I copy/paste the data? I did one a while ago but forgot how and where to move the data.

    TIA
    2007 Silver Z06

  4. #4
    Lifetime Member
    Join Date
    Jun 2003
    Posts
    205

    Default

    User Configuration\calc_pids.txt


    Attached my calc_pids for you, easier then cutting and pasting.

    just make sure mine don't stomp on any of yours.
    Attached Files Attached Files

  5. #5
    Member
    Join Date
    Mar 2007
    Posts
    64

    Default

    could you pleas explain how to do this. im am computer illitertate but im trying. thanks.

  6. #6
    Member
    Join Date
    Mar 2006
    Posts
    91

    Default

    Check out the calc_pid listed in post #8. It contains the formulas needed for rolling resistance and aero drag. I have not worked on it for a long time, but am willing to continue to de-bug it with others' input.

    http://forum.efilive.com/showthread.php?t=2312

  7. #7
    Lifetime Member Chalky's Avatar
    Join Date
    Sep 2003
    Posts
    616

    Default

    Anyone tried the formula/pids? I tried these today and they seem to be on the low side by possibly 8-9%.

    My RwHP using the pids put me @ 400. based on my setup, I am closer to 440 RWHP.
    2007 Silver Z06

  8. #8
    Lifetime Member
    Join Date
    Jan 2007
    Posts
    293

    Default

    Which one did you use?


    The one that you speed up over a certain range and coast down over it?
    Or the regular one?


    I have been meaning to make one that does it all at once with my Cda and rolling resistance plugged in as a function of speed in but keep getting distracted. At least this way you don't have to low down over the same range each time.

    Only thing about the A+B method is if the wind and grade are constant during the test it figures those in. Other small changes too!

  9. #9
    Lifetime Member Chalky's Avatar
    Join Date
    Sep 2003
    Posts
    616

    Default

    I used the most current one with txt provided by DBaxter.

    Formula is working. I added 100 lbs to formula and HP did increase. maybe car weights are to light.

    I didn't realize there was a difference or a process to implement to achieve proper results.
    2007 Silver Z06

  10. #10
    Lifetime Member
    Join Date
    Jan 2007
    Posts
    293

    Default

    You stated you were about 40 horses short? How fast were you moving? Aproximately 80 MPH?

    I like the equation that DBaxter provided it is easy and simple but depends totally on speed. Wind resistance is left out.

    I used info from the Cat link to make up this quadatric regression:
    y = ax^3+bx^2+cx+d
    where
    A = 5.7358e-5*x^3
    B = 2.0635e-3*x^2
    C = 4.3544e-3*x
    D = -5.582e-04

    Where X is {SAE.VSS.mph} and Y is HP lost due to rolling resistance and wind resistance.

    If you put that into the function then it wouldn't show 0 when you were driving at the same speed all of the time. Also, it would help you realise a number closer to the dyno number of your car.

    Of course this is going to vary from car to car due to AERODYNAMICS and fiction from our drivetrains, bearings, and tyres. We should be free from weight.
    Last edited by 2002_z28_six_speed; October 3rd, 2007 at 02:45 PM.

Page 1 of 7 123 ... LastLast

Similar Threads

  1. 1000+ rwhp Z06 with an E38
    By E.A. in forum E37, E38 & E67 PFI ECM's
    Replies: 13
    Last Post: March 10th, 2010, 04:47 PM
  2. Calc.rwhp
    By TFZ_Z06 in forum Black Box Logging
    Replies: 4
    Last Post: October 27th, 2008, 11:56 AM
  3. Logged RWHP?
    By Spindoctor in forum Gen III V8 Specific
    Replies: 3
    Last Post: October 23rd, 2008, 11:14 AM
  4. Made 751 Rwhp On Only 14 Psi Thanks To Efilive!! Vid!
    By nitrorocket in forum General (Petrol, Gas, Ethanol)
    Replies: 2
    Last Post: June 7th, 2006, 01:59 PM

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •