True HP PID

Don't want this lost in the other post.

Just add to the calc_pids.txt

400 or whatever you think your max hp should be.
3554 is the vehicle weight ( replace with your value here )
185 - driver weight ( and passenger(s))
,6 is the change in (x) polls. I used 3 different ones. One at 1,6,12

chose the sae.vss.mph and gm.fuelrem pid then you are all set. You can add in the hp pids later to review or have them real time.

# Add slot definitions here
*CLC-00-989
hp 0.0 400.0 .0 "(((3554+({GM.FUELREM}*6.350)+185)*{SAE.VSS.mph})* dx({SAE.VSS.mph},6))/8226.63"


*PRN - Parameter Reference Numbers
CALC.SSHPTRUE6 F60A CLC-00-989 "kW,hp" Performance "SS TRUE HP 06"


http://www.purplegto.com/files/42to83.PNG

What about aero and rolling drag corrections ?

That pid calculates HP left over to accelerate the vehicle after all resistance/friction has been overcome (i.e. "road HP" rather than dyno HP);

if you know how to compute aero/rolling/drag corrections then add them on and you got dyno HP.

:cheers:

With this pid you can roughly compute flywheel hp....

On a given stretch of road:
a. log accelerating at WOT all the way to speed X;
b. in the same direction, log coasting (neutral) down from speed X;

a will give you positive hp numbers;
b will give you negative hp numbers;

at each MPH compute (a - b) and this is approximately flywheel hp;

this can be close if you don't spin, and if you do a and b minutes apart.

a is engine power minus all the losses.
b is only all the losses.

Of course this assumes you have dfco on immediately!?

Quote:

---

Originally Posted by ringram

Of course this assumes you have dfco on immediately!?

---

If the trans. is in neutral, then it won't matter.

Not to nitpick, but technically you need to have the clutch disengaged to keep from turning the input shaft of the trans.

Can someone tell me why the following PID will not work? It is identical to the 'CALC.POWER_RW' except I use my 'CALC.SPEED.mph' for higher resolution. The PRN numbering appears to be correct and should calculate the speed before calculating the power. 600 and 601 work properly.

By the way, the following PIDs will calculate true rear wheel Hp with rolling resistance and aero drag. The only variables left out are road inclination and wind.

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

*CLC-00-600
mph 0.00 160.00 .2 "{GM.TOS}*28.68/(3.73*336.135)"
kph 0.00 260.00 .2 "{GM.TOS}*728.47/(3.73*5305.16)"

*CLC-00-601
Roadhp 0.0 400.0 .1 "((0.012*5060)+({GM.BARO.inHg}/({SAE.IAT.F}+460)/22.0824*0.506*20.125*{CALC.SPEED.mph}*{CALC.SPEED. mph}))*{CALC.SPEED.mph}/375"

*CLC-00-602
RealHp2 0.0 400.0 .1 "5060*{CALC.SPEED.mph}*dx({CALC.SPEED.mph},5)/8226.63+{CALC.RLHP}"

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

CALC.SPEED F600 CLC-00-600 "mph,kph" Performance "Speed Calc"
CALC.RLHP F601 CLC-00-601 "Roadhp" Performance "Road Load Hp Losses"
CALC.REALHP2 F602 CLC-00-602 "RealHp2" Performance "Real Horsepower"

Send me a log with the correct pids so I can check it against mine. I think I have it all setup right for you.

Here is the short log I took to test the PIDs.

I am going to try and get with you in a few hours to go over this with you if you are around. Can you get some WOT runs to see how it looks at WOT.

I tried the RWHP PID with a known Dyno tested 50 Shot. On the dyno The 50 shot was 341 RWHP, The PID had it at 344 on the street. Not to shabby within 1%...:cheers:

Those are pretty much equal... :cheers:

Is CALC.RLHP "RoadHP" the amount lost due to road/air...?

Yes, the 'RoadHp' calc is the Hp lost due to rolling resistance and aero drag. I had to use IAT values to calculate the "actual" air density since the I6 cal file does not recognize the ambient air temperature sensor.