Best way to monitor clutch slip

[robz]

What pid would best monitor this?
I figure watching the rpm is one way.
Is there anything for input shaft speed?
Any suggestions to monitor this?
Thanks

[mistermike]

VSS and RPM should be at a fixed ratio in gear. If they drift apart, the clutch is slipping.

[robz]

VSS and RPM should be at a fixed ratio in gear. If they drift apart, the clutch is slipping.
anyone else?

[joecar]

Create a calc pid for this: Trans Input RPM = VSS * 336 * GR / TD

where:
VSS = vehicle speed [MPH]
TD = tire diameter [inches]
GR = overall gear ratio = trans ratio * axle ratio



T56 in 3rd gear (1.30), thru 3.46 axle at 70 MPH on 275/40R17 tires

TD = 2 * (275 * 0.40) / 25.4 + 17 = 25.66 inches

GR = 1.30 * 3.46 = 4.498

Trans Input Speed = 70 * 336 * 4.498 / 25.66 = 4123 RPM

Then in your log you can compare engine RPM to Trans Input RPM, or you can create a calc pid for RPM / Trans Input RPM.

This is what Mr.Mike is saying to do.

Cheers,
Joe
:beer:

[robz]

Create a calc pid for this: Trans Input RPM = VSS * 336 * GR / TD

where:
VSS = vehicle speed [MPH]
TD = tire diameter [inches]
GR = overall gear ratio = trans ratio * axle ratio


Then in your log you can compare engine RPM to Trans Input RPM, or you can create a calc pid for RPM / Trans Input RPM.

This is what Mr.Mike is saying to do.

Cheers,
Joe
:beer:
sent pm

[joecar]

Replace calc_pids.txt with the following [see attached file]

(be sure to first save your existing calc_pids.txt):



# ================================================== ============================
# File details
# ------------
#
# This section defines various details about the file format.

*FILE

#Parameter Value Description
#---------- ---------------- ---------------------------------------------------
VERSION 7.1.1 File version
DECSEP . Decimal separator used in this file



# ================================================== ============================
# Units
# -------------------
# See sae_generic.txt for more information on the *UNITS section

*UNITS

#Code System Abbr Description
#-------- ---------- -------- -------------------------------------------------------------

None None "" "No units"
inch Imperial "in" "Inches"


# ================================================== ============================
# Add slot definitions here
# --------------------------------
# See sae_generic.txt for more information on "SLOT" formats
#
#Units Low High Fmt Expression
#------------ ------------- ------------- ---- --------------------------------------------------------------

*CLC-00-080
inch 0.0 60.0 0.2 "26.2"

*CLC-00-090
factor 0.0 10.0 0.2 "4.10"

*CLC-00-101
rpm 0 8000 0.0 "{SAE.VSS.mph} * 336 * {CALC.AXLE} * 2.66 / {CALC.TIRE}"

*CLC-00-102
rpm 0 8000 0.0 "{SAE.VSS.mph} * 336 * {CALC.AXLE} * 1.78 / {CALC.TIRE}"

*CLC-00-103
rpm 0 8000 0.0 "{SAE.VSS.mph} * 336 * {CALC.AXLE} * 1.30 / {CALC.TIRE}"

*CLC-00-104
rpm 0 8000 0.0 "{SAE.VSS.mph} * 336 * {CALC.AXLE} * 1.00 / {CALC.TIRE}"

*CLC-00-105
rpm 0 8000 0.0 "{SAE.VSS.mph} * 336 * {CALC.AXLE} * 0.74 / {CALC.TIRE}"

*CLC-00-106
rpm 0 8000 0.0 "{SAE.VSS.mph} * 336 * {CALC.AXLE} * 0.50 / {CALC.TIRE}"


# ================================================== ============================
*PRN - Parameter Reference Numbers
# --------------------------------
# See sae_generic.txt for more information on the *PRN section
#
#Code PRN SLOT Units System Description
#------------------------- ---- ------------ ---------------- ---------------- ------------------------------------------

CALC.TIRE F080 CLC-00-080 inch Testing "Tire diameter"
CALC.AXLE F090 CLC-00-090 factor Testing "Axle Ratio"

CALC.TIS_1ST F101 CLC-00-101 rpm Testing "Trans Input Speed 1st Gear"
CALC.TIS_2ND F102 CLC-00-102 rpm Testing "Trans Input Speed 2nd Gear"
CALC.TIS_3RD F103 CLC-00-103 rpm Testing "Trans Input Speed 3rd Gear"
CALC.TIS_4TH F104 CLC-00-104 rpm Testing "Trans Input Speed 4th Gear"
CALC.TIS_5TH F105 CLC-00-105 rpm Testing "Trans Input Speed 5th Gear"
CALC.TIS_6TH F106 CLC-00-106 rpm Testing "Trans Input Speed 6th Gear"





Of course, if you have other calc pids in your existing calc_pids.txt, you need to copy the 3 sections above (colour coded) to your calc_pids.txt without disturbing your existing definitions.


:cheers:

Edit History:
0. initial post.
1. changed MPH to RPM.
2. changed SAE.VSS to SAE.VSS.mph.
3. changed gauge/chart high to 8000.

[joecar]

After copying the calc_pids.txt file do this:
- start the scantool,
- open your log file,
- goto the PIDs F8 tab,
- select the tire and axle calc pids shown in the attached pic,
- select whichever other TIS pids you want,
- press the replot button,
- on the dash tab, add the TIS pid(s) to your chart display
- press the replot button.

[Bruce Melton]

I guess you are referring to what I might call "runaway" which is slip after engagement? It seems this is how many LS clutches overheat and first fail > in third gear near max torque?

[Ninety8C5]

Create a calc pid for this: Trans Input RPM = VSS * 336 * GR / TD

where:
VSS = vehicle speed [MPH]
TD = tire diameter [inches]
GR = overall gear ratio = trans ratio * axle ratio


Then in your log you can compare engine RPM to Trans Input RPM, or you can create a calc pid for RPM / Trans Input RPM.

This is what Mr.Mike is saying to do.

Cheers,
Joe
:beer:

If the PID is calculating Trans Input Speed, shouldn't the PID be RPM instead of MPH in the calc_pids file?

I think you need to add mph to {SAE.VSS.mph}. The numbers looked high without it.

[joecar]

If the PID is calculating Trans Input Speed, shouldn't the PID be RPM instead of MPH in the calc_pids file?

I think you need to add mph to {SAE.VSS.mph}. The numbers looked high without it.Ah, yes RPM not MPH, slipping brain... :cheers:

[joecar]

Thanks for the feedback, I recorrected post#6.

[robz]

Thanks you Joe!
and thanks for the MAF Bruce M.

[mistermike]

This is what Mr.Mike is saying to do.

Cheers,
Joe
:beer:
But, said so much more eloquently by you.

Great job, joe.

[joecar]

Thanks Mike... :cheers: