I drive a MKIV GTI and just got a VAG-COM for those of you in the VW world.. I was very impressed to find out you can datalog many things with this.. but most impressive of all is that you can datalog RPMs and current load. From this you can calculate torque (ft/lb) by multiplying the currently load * .738. You can then calculate horsepower as it is a function of torque over RPMs... It was then a matter of making a chart for a full dynoplot.

I'm also building a turbo LS powered del sol running uberdata and was wondering if the same calculations could be done to graph a dynoplot on the street.. anyone have any experience with this, or are the current load values from the VW adjusted by the ECU?

TIA

 

Crome does it already, last I heard, it was in development for Uberdata as well

 

So using the same constant - .738 is standard across the board I assume? It's easy enough to throw into excel and make some calculations in order to draw the graph..

Thanks!

 

I would *think* (I'm far far far from being an expert and I haven't spent too much time reading the PGMFI/Uberdata discussions on this) that the load * 0.738 might be true for a stock Volkswagen, but it might not hold true for one that has had modifications done, ie., the 0.738 is an estimation of the volumetric efficiency or something of that sort. Load would be MAF, 0.738 would be a calculated constant, torque would be the result. Or perhaps load value would change for a modded VW because the MAF readings would change. I don't know enough about it.

Thoughts?

 

The writeup I found on how to do it showed examples of it being done on modded cars using the same constant (.738).. I was wondering the same thing though, and nor am I an expert. The one factor that I came up with that could change things significantly is the weight of the car.. but that really wont' change much.

Any idea of what constant Crome uses?