gm.trqeng

99 c5. what are the inputs for torque in a stock tune? what happens if you loose the maf? and how is it with cos3 and (e.g.) a 2bar map?

(gm.trqeng seems to yield same values as gm.trqtrans. any thoughts on that?)

edit: this is what im seeing at 200kpa/no maf. (i cant upload scan for some reason.) rising ibpw to redline, dyncylair rising to redline (1.90 max), torque peaking at 3800* with a (quite realistic for max) value around 800 nm, acceleration fluctuating but highest at 5000-6000, calc.power rising to redline with 500 rwhp max (not unrealistic, a bit low). in a stock cofiguration i see max torque at 450 nm (engine rating is 475).

*140kpa

Ive never tuned a MAF for boost so i have no idea on this one.

speaking of dyncylair: its seems overreported by about 40% in the cos3 tune.

stock car reports 0.71 g at torque peak. 0.721 liters x 1.175 (15 degrees c, 300m, 50%) is 0.846 g, working out to 84% vol. efficiency. cos3 reports 1.71 g at 5500rpm/190kpa*. 0.721 liters x 1.117 (30 degrees c, 300m, 50%) is 0.795 g x 1.9 p.r. = 1.51 g. 1.21 g at 80% efficiency. 1.71/1.21=1.41. it would mean 113% cylinder filling.

any thoughts on that? if the inputs were known the numbers could be somehow scaled back, i guess.

*i took this point because the 2bar map is still well within its range.

GM.TRQENG and GM.TRQTRANS should read the same for combined engine/trans PCM.

When MAF fails PCM sets a MAF DTC, sees this and then does SD (VE table) only.

So you need to get both MAF and VE tables corrected.

In COS3 are you MAF-less (i.e. SD, VE only)...? How did you verify this (or not this)...?

If SD might have to look at temperature correction airmass tables.

maf is gone.

so are you saying the ecu looks at map and iat only to calculate torque/dyncylair? (obviously it understands boost wit cos3.) how does it then happen it thinks they are highest at low rpm/bosst (3800/140kpa)? iat* is the same and i surely do not have the largest v/e numbers in the midrange, they are rising up to redline.. a stock car reports highers tq/cylair around 5000 btw.

*in both cases maf would be well beyond the 120g/s blending table limit

ECU first calculates airmass using MAF and/or VE, it then calculates everything else, including fuel mass and ignition advance.

Are you getting a MAF DTC...?