A8 1.2TDI is alive registered and running lean
 

1997 Audi A8 1.2 TDI 6 speed manual Gas Mileage (A8 luxury fuel sipper) - EcoModder.com

Very good result in my first calculated "tank".
5.62 L/100 km
41.9 mpg (US)
50.27 mpg (Imp)
2.39 gal (US)/100 mi
804.38 Wh/mi
https://scontent-arn2-1.xx.fbcdn.net...3f&oe=56466B92

Congratulations on this epic conversion! You always have interesting projects but the work involved is a testament to your ingenuity and tenacity. Would the Audi be about the same weight as your Passat now? I think the 1.2 TDI is about 250 pounds so did the car loose about 200 pounds after the conversion? I bet the handling is much better now.

Good to see this project up and running :D

I wonder if a 1.2 is actually too small and running high loads means richer AFR's?

That's an epic project anyway.

That's an awful lot of mass to tow around with a 1.2. I reckon once it gets up to speed it isn't too bad though. God knows the TDI engines make good torque for their size, if you have the time I don't doubt it'll accelerate up to highway speed eventually.

Have you done any aero mods to ease the engine's workload at cruising speed?

Diesel engines do not regulate AFR, there is no throttle. As long as the turbo supplies enough air, the AFR will be lean under all load conditions.

Well, nowadays that Ford uses a 2.8L turbodiesel in the Brazilian version of the F-350, let's give some credit to the 1.2L in Vekke's A8.

He shows it weighing 1605 in his avatar info but I think he means 3500 pounds. Thats roughly my SUV's power/weight ratio. I have under 160hp/torque and he lists 120hp and 285NM which is about 211 ft/Lbs I think. He's getting that power around 1500 rpm and I have to rev my socks off to what I have. I don't think I've ever used more than 130 hp to merge onto the highway giving it the full beans according to scangauge. I don't think that Audi would seem sluggish. Heck, most of the time I'm using 20 hp to climb hills in town and less than that when I'm getting 40+ mpg. The Amarok truck uses the VW 2.0 with turbos to do 4x4 duty too.

Considering that it has a lower GVWR and is more aerodynamically-enhanced than many Euro and Jap vans from the 90's which had lower power and torque ratings, but still have a safe road performance, I would also assume it's going to be anything but sluggish.

Second tank data are ready, so took some trip as weather was very warm in this summers scale on Finland +25 celsius in the evening and +17 on the night at the moment.

4.24 L/100 km
55.55 mpg (US)
66.66 mpg (Imp)
1.8 gal (US)/100 mi
606.69 Wh/mi

Had 50 km of traffic light driving in the beginning of the tank. Cam timing is now adjusted from -2.2 degrees to 0 degrees. That seemend to help quite much specially to low end torque.

Rest of the tank tried to drive 100 km/h avg speed as much as possible.

AVG temperature +22 celsius.

Measued odo trip error to be 1% so that is now corrected.

Speedo error is -6% which is also corrected for the avg speed.

Lot of black smoke is coming on bigger uphills so the ecu tuning is still way off before its fixed to this turbo and car. One driver opened his window on highway and warned that is my engine OK due to that smoke.

I would not say this is slow already at current state, even its not working perfectly yet ;).

Weight of the car is 1430kg at the moment plus driver which in my case is +100kg. With current level of fuel I would say under 1600 kg easily total in driving condition.

Although the mechanism differs from petrol, diesels main party trick is changing AFR to suit load conditions. A diesel can run 100:1 at idle and 14:1 under load. If diesels always ran lean, they wouldn't make smoke under heavy load - even the latest BMW will put out visible smoke if driven hard.

Renault is one of the first in modern times to go to a really small engine for a really big car, in the Trafic, you get 1.6 litres to move a 1700kg van. It still does 0-62 in 10.8 seconds (still faster than some hatchbacks), and is rated for a total train weight of 5 tons :D

Looking at Vekke's figures, his car has the same power for less weight and a better frontal area. I thought the first tank was a disappointment, but the second tank shows promise. I'd have hated all that work to have gone to waste. But it looks like a 'fast enough' car that will do 60mpg now :thumbup:

Sure, I see plenty of overpowered diesel pickups that smoke like trains, but that's because they've chipped them to make more power by adding fuel. But in a factory setup, it's difficult to make them smoke because they are designed to be clean. Volkswagens are some of the cleanest around. When I get mine emissions tested (at load), it regularly turns less than 6% opacity. They are designed to run lean of stoichiometric.

So, what are you considering to do in order to overcome the smoke issue?

Its just a matter of ecu tuning in my case. ecu tries to get more boost even its not capaple to deliver so it injects more fuel. The Turbos vnt control is not fully in use due to program is for smaller turbo whichs boost peaked a lot so its not closing totally the vanes in current program.

There are 3 "programs" in depending on my gas pedal position.
0-70% is at the moment very efficient but no boost is the 2 liter fuel consumption range. 70-90% is efficient acceleration with 0.8-1 bar boost
90-100% is flat out acceleration (all in) with 1.5-1.7 bar boost

at the moment the car goes on to that 90-100% range on bigger uphills and gives smoke.

If I remember right from my mark 4 VW days the 1749 was an up sized turbo for those 1.9 liter TDI and even in factory form they would go just fine with 90 hp and 177 Ft/Lbs.

Got the vehicle weight down to under 1500k - WOW. That's a lot of dieting!

I don't think I had accurate numbers to look at for the 1.2's output. If it's going as well as all that, I think the numbers I saw were either old or just flat wrong.

I let the large size of that car distract me from the fact that it is an aluminum monocoque platform. Its very light for its size! There is even a picture of one with polished aluminum--no paint.

Today tested acceration and result was 10.5 seconds average for 60-120 km/h acceleration.

Weighted the car in corner weigth scales and resuts were:
Front Left....Front Right
420............430kg

Rear Left......Rear Right
300 kg..........320kg (12V battery is in this corner.)

Total 1470 kg with full tank in this measurement.

That's not bad for a big car. 3240 US pounds for the metric-challenged.

Today got new record:
3.39 L/100 km
69.42 mpg (US)
83.31 mpg (Imp)
1.44 gal (US)/100 mi
485.42 Wh/mi

Neste green diesel works better.
50% of the tank +100kg
80% tank @ 100 km/h (avg speed 88 km/h
last 60 km of the tank in heavy rain.
avg temp on whole tank about +25 celsius
cars computer was 4.3 l/100km so error 21%

Next tank will be with "new" injectors so it should be much better as these current ones are not working at all.