Diesels - LONG

["Robert B." <robbrauns@bb.eulink.net>]

Hello List:

This is a really long email about diesels, so I've made a little help
guide so you can skip this long email:

|<--- START
| A few people on this list wanted to know about diesels, biodiesel and
converting, so here
| are my answers. First, I'll start with biodiesel:
| The biodiesel website makes it sound like you can get a barrel of used
french fry oil,
| add some methanol and drive around for pratically nothing. If you look
at their website,
| they give giblets (bit sized pieces of information that can be
swallowed whole, without
| thinking first) and then tell you to buy their stupid book! Don't buy
it! Here's why:
|
| 1. Biodiesel does not have the sulphur found in mineral oil diesel and
since sulphur is
| used to lubricate the injector pump, you will end up wearing out the
injector pump
| much faster than normal. Oh, I guess that's in the book.
| 2. Biodiesel has different emissions and a lot more particulates than
regular diesel, so you
| will end up destroying your oxi-cat (more on this later) real fast. If
you notice, the van
| they used was old enough that it didn't have a cat. Hey, thanks for
buying our book!
| 3. The effeciency of making your own biodiesel is about 40% meaning
that not every
| bit of vegetable oil is converted to useable fuel. Here's the problem:
the sludge left
| over from converting french fry oil to biodiesel is considered toxic
waste and needs to
| be specially disposed of. Wow, aren't you glad that you bought our
book?!
| So, forget biodiesel for now.
|
| PLEASE KEEP GOING IF YOU WANT TO SKIP THIS LONG EMAIL. VAG:
|
| The VAG make TDIs with a lot of differences. FWIW, TDI is registered
by VAG, so
| no other car company can call their engines TDI. Mercedes uses HDI and
others use
| CDI, etc. Only the VAG group of cars can be labelled TDI. Anyway, the
TDI engines:
| There are 3 kinds of 4 cylinder diesels, 3 kinds of 5 cylinder TDIs, a
V6 and a V8
| diesel from VAG. All TDIs use an electronically controlled injector
pump and oxi-cats.
| 1. 4 cylinder TDIs come in 90, 110 and 115 HP flavors.
| 1a. Only the 90 HP TDI is sold in North America. This engine uses a
normal turbo and
| an electronic injector pump. This is the older version of the TDI but
can be chipped to
| produce 110 HP. The cat is used to reduce NOx and is not a 3 way cat.
More later...
| 1b. The 110 HP TDI uses a variable vane turbo providing more low end
boost and
| modified electronics (chip) for 20 additional HP. These engines can be
chipped to 140
| HP. BTW chipping these engines usually gets you better fuel economy.
| 1c. The latest generation of TDIs are radically different and use a
Pumpe-Düse. There is
| no longer a big injector pump bolted to the side of the engine, but
rather a tiny injector
| pump for each cylinder built into the head. The pump is actuated by a
cam lobe and
| develops 2050 Bar (30,000 psi!). These newest engines use 4 valves per
head, mount the
| injector in the center of the cylinder and meet Euro-Norm III
emissions specs. A Passat
| with this new motor does 0-60 mph in 10.8 seconds, develops 115 HP and
300NM of
| torque (more than a VR6!). My neighbour has a Passat with this motor
and he tells me
| that is starts, runs and drives like any gas engine. Chips are
becoming available to boost
| the HP to around 170. It is very quiet and is a BIG sensation here in
Europe, especially
| since VW is offering 4-Motion (modified Synchro NOT a true Quattro
system) with the
| new TDIs and also 6 speeds for better fuel economy. Injectors and ECU
are Bosch.
| 2. 3 kinds of 5 cylinder TDIs were/are available and are rated at 110,
140 and 102HP.
| 2a. The 110 HP 5 cylinder TDI is based on the 2.2L 5 cylinder gas
engines and is the
| same as the 90 HP TDI with an extra cylinder. Can be chipped to 140
HP.
| 2b. The 140 HP 5 banger also uses variable vane turbo technology and
can be chipped to
| 170 HP and over 400NM of torque (more than an S2!). These engines are
sadly no longer
| manufactured and were available in the Audi 100 and later A6.  Quattro
was offered.
| 2c. The only 5 cylinder TDI still made by VAG is rated a 102 HP and is
available in the
| Eurovan. I haven't seen chips for it. BTW the engine sits sideways in
the Eurovan.
| 3. V6 TDIs replace the 5 cylinder ones and these use 4 valves per
cylinder, variable vane
| turbos and an electronic injector pump. Not sure of the HP, but I
believe that the 2.5L
| V6 is rated at around 140 HP. Injectors and ECU are Bosch.
| 4. The newest A8 has a 3.3L V8 with 2 variable vane turbos and a
water-air intercooler
| in the middle of the V. This motor uses common rail technology and
puts out 500NM of
| torque. I can't remember the HP figure, but it is around 400. BMW and
Mercedes also
| offer V8 diesels and these new motors put out enough to spin the drive
wheels.
| All new VAG diesels use an oxi-cat that reduces NOx emissions and
Peugot is working
| on a particulate burner that burns the small particles created by a
diesel. Diesels in
| Europe have come a long way since the 80's, but due to the lack of
consumer interest,
| North Americans don't get the best diesels. I believe that diesel is
also more expensive
| than gas in America, so that might be part of the reason.
|
| ALMOST DONE! CONVERTING TO A DIESEL:
|
| If you want to convert your Audi to a 4 cylinder diesel, this is
roughly what you have to do:
| 1. All 4 cylinders, VR5 and 6's use the same engine mounting as the
old 1.8 and 2.0L gas
| engines, BUT the bellhousings are different between the 4 and 5
cylinder motors, so you
| would need the transmission, engine mounts and accesories from a 4
cylinder Audi. Audi
| Europe offered a 4 cylinder Quattro, but these are very hard to find
since most Quattros
| were sold with 5 cylinder motors. This would only work on a FWD car.
For a Quattro, you
| would need to find a 5 cylinder TDI motor and I haven't be able to
find one myself.
| 2. You have to change the fuel tank to a diesel one. This is because
the filler necks are
| different and gas engines have a fuel return line that recirculates
fuel back into the tank.
| Diesels do not have this return line, so you would need to change the
tank or plug the
| return line. I also believe that the lining inside the tanks are
different, but I'm not sure
| about this.
| 3. You would have to figure out how to run the tach and get the trans
signal to the ECU,
| since the TDI computer measures speed to determine engine load and
adjusts the fuel
| accordingly. MAYBE a Torsen that already has the electronic speedo
signal could be
| made to work, but that means finding a 5 cylinder TDI engine again.
| 4. Diesels don't have an ignition, so running the tach signal would be
difficult. I believe
| that TDIs have a TDC sensor to let the ECU know where TDC is and this
same signal
| is used to determine engine RPM, so you might be able to use the tach
still. On the subject
| of RPMs, the TDIs redline at 4500 RPM, but power drops off fast after
4000, so sporty
| driving is definately out of the question. Max torque is available at
1900 RPM, so that's
| why spinning the front wheels is easy. You can modify a diesel to let
in more air by
| porting and polishing the heads, but without more fuel injected into
the firing chamber,
| the engine will not produce more power. Larger intercoolers also help
and reduce turbo
| lag, which is very small with a TDI to begin with.
|
| I hope this LONG email helps clear up any questions about diesels.
|
| Kind Regards
| Rob in Germany
|
| --> WHEW! END OF LONG EMAIL.