Andy@Ross-Tech

This applies to drive-by-wire 1.8T's and 2.7T's. DBW 2.8 and 3.0 may have the same torque calculation in group 122. One of our customers came up with this excellent tutorial spreadsheet and gave us permission to link it from our website.

The torque calculation in Bosch ME-Motronic ECU's is just that, a calculation. The good folks at Bosch (who literally wrote the book on how engines operate) have a pretty good idea of how much torque an engine is generating at a given moment, based on a multitude of sensors as well as knowledge about the specific engine design (volumetric efficiency, number of cylinders, etc.). The ECU tries to come up with a plausible figure for torque in Newton-Meters (Nm) as "Net Flywheel Torque". This is supposed to be comparable to torque measured by load cells on an engine dyno, so the resultant figures are "crank", rather than "wheel".

One problem with using 120 to figure out your vehicle's performance is the effect of performance modifications. First of all, changing the fuel pressure regulator (say from a 4.0 bar to a 5.0 bar) will throw these calculations WAY off. The ECU doesn't know that you are now dumping in 25% more fuel every millisecond that the injectors are open (it won't be exactly 25%, but you get the idea). Also, some performance chips do things to the engine's running parameters that throw these calculations off.

The moral of the story is 120 is interesting, and in some cases, very accurate, but don't yell at your chiptuner if your 120 results show you only got 190 hp instead of the claimed 215 hp. :-)<ul><li><a href="http://home.earthlink.net/~cogent001/vw/Block_120_Tutorial.xls">UKAussi's Block 120 Tutorial</a></li></ul>

Singletrack

<center><img src="http://pictureposter.audiworld.com/25380/vag-torque.jpg"></center><p>
VAG-COM is the best investment I've made in my car.

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