[Vwdiesel] Playing with Vag Com

[Val Christian]

I've been trying to solve a couple of problems on my TDI, so today
I drove it around, with VAG-COM running.  It was kinda windy, so 
I thought I'd have some fun. 

On the expressway, I was able, with a 30 knot tailwind, to run for about 
5 miles on level ground, averaging 80 mpg, doing 65 mph.  Dropping the speed 
10 mph didn't help much, although in theory it should.

Bucking into the same headwind, the 5 mile run was 42 mpg.  However, I 
tended to notice 36 or 37 mpg when I looked at it.  Not apples and 
apples, because I did 55 into the wind.

The TDI will drop injection to "0" going down a hill, or braking with the
engine.  That's about what I expect.  In the winter, when temps are
around 0F, you can watch the coolant temp gauge drop, while going down
a slight grade on the expressway.

Firing up the rear window defogger takes about 0.12 liters/hr of fuel.

The heater blower takes a bit more, 0.22 on high.

Temps were about 50F, but the coolant sensors showed coolant dropping
temp when driving with cruise control down 1 mile slight descents.

I estimate that DRLs take about 0.05 litre/hr, which probably translates 
to well over 100 gal over the life of the car.  More if city driving.

The cruise control on my 03 Jetta has a pretty good servo setup.  It 
keeps the RPMs within 1.5%, over my test period.  I betcha a TDI hacked
into a genset would have pretty good frequency control, assuming the 
constants could be hacked to shorter time constants, etc.

If I could get a PDA sized device to run VAG COM then I could panel mount 
one, and I'd really have fun.  Running the laptop in the right 
seat makes me as dangerous as cops who drive around running their laptops
on the road.

Merry Christmas.

Val