- Are you pulling my leg?
- What's the fuel economy of veggie oil vs diesel?
- Is there any loss in power / acceleration?
The power question I can never answer definitively since you need special equipment to perform the test. That and my 2001 JettaTDI sedan is spec'd at 90 hp - not exactly a hot rod.
So when the local Ottawa Volkswagen enthusiasts group had their annual dynamometer day (wiki), I paid for two runs on the device. One diesel, one veggie.
For both runs the engine was hot for ideal performance (20min driving at 80km/h). For the veggie run, I made sure I was running on veggie for at least 10min before the test started - 100% veggie no diesel on the side. The oil temp was over 70C.
1) Calibration. Dynos need to know what wheel speed your car has in relation to the RPM of your engine. With that, they can graph torque and horsepower against engine speed. They say it was tricky because they rarely test automatic transmissions.
2) The first run.
3) Under the hood. See all my foamy fuel-line insulation? See my foil bubble wrap FPHE and GreaseCar fuel filter insulation?
4) Computer display. Wheel speed in kilometre per hour at bottom left. Engine speed in rotations per minute converted from wheel speed at bottom right.
5) Up close. Look at that monster (cough) engine heave under the hood. Seriously, I didn't realize they do that.
The Results (drum roll)
Click to enlarge
Veggie (in green) - 192 ft-lb Torque, 107 hp
Diesel (in red) - 172 ft-lb Torque, 102 hp