Hello folks,

I just finished using Craig's software for hte first time (BTW Beautiful job works great!) and I'm getting TPS voltage % of -1.7 the actually volts is .47 (This is at idle. haven't drove yet) any ideas what could be causing this? should I just adjust the TPS?

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1987 IROC-Z T-Tops wait... GUTTED MAF!

 

That's OK, it's how %TPS is being calculated by the software. The computer has it's own way of calculating %TPS that isn't even sent in the data stream to the ALDL. I think there's a default table in Craig's software where you tell it what your initial and WOT TPS voltages are, from which it can correctly calculate %TPS.

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Greg Westphal
'87 IROC 355TPI/A4

 

In the change defaults selection from the main menu, you can tell the software what the baseline and top TPS voltages are. The defaults are .54 and 4.7 (I think). Change these to your actual values to get accurate % measurements.

Bob

 

I don't know my actual measurements. but I can do without. also at one point (about 2200 RPM) the software is reporting I have 300 HP. How accurate is the HP formula in the software?

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1987 IROC-Z T-Tops wait... GUTTED MAF!

 

The program itself will act as a DVM for the TPS. Let it sit at idle & look at the TPS voltage. Then hold it to the floor hard and look at the TPS volts again. Plug these numbers back into the defaults menu.

The horsepower numbers are not ones I'd take to the bank. They are based on a couple of things, such as max velocity, horsepower consumed to maintain velocity, vehicle weight, change in speed over time, essentilly the equations of motion.
net F=ma =applied force-force for max velocity
a=dU/dt=d(mph)/dt
U=dx/dt=mph

Make sense? The values for mph and time are registered every 2 seconds, so to imagine it, just picture your speed at time "10 seconds", then compare it to your speed at time "12 seconds". Plug that into the equations above, and you get HP, or work per unit time, that is,
HP=dW/dt
W=F*d
d=mph(avg)*dt
F=net force=Fapplied (your power) - Fdrag (from max velocity, assumed 140mph).

Anyways, I'll not go into any more detail at this point other than the HP calc is relative, kind of like the 1/4 mile calculator, and can only be as accurate as the input data...

 

Was evaluting some software one time, and saw a flash reading of 575 HP, on the 2-3 gear change. Needless to say the tire spin really screwed up the HP calculation, I figure was at least 5% off LOL.......
Not bad for a lil v6.