LAC Biodiesels, Diesels, TDI's,etc...

[Lee Levitt]

Yep, BTDT. Came back.

I bought a '93 300D 2.5L turbodiesel (W124 series) with the plan 
of producing and using biodiesel. There's very minor work involved 
in prepping a pre mid-90s car for biodiesel use, primarily 
replacing all fuel lines with Viton branded lines. Early lines 
will eventually be degraded by the biodiesel, which is a pretty 
good solvent, and will weep fuel. The Viton branded line, supplied 
as OEM in later vehicles, is available by the foot, and can be 
retrofitted fairly inexpensively.

Biodiesel is not generally publicly available...there's only a 
single pump in all of the Boston area, and the price is equivalent 
to regular diesel. The good news is that diesel cars generally get 
better fuel economy...my MB got 35 mpg on the highway at 75 mph, 
and never dipped below 30 mpg in the city, no matter how hard I 
pushed it. (Diesels love full throttle!)

The alternative is to convert the vehicle to a "grease car", where 
you'd have a second tank in the trunk for waste vegetable oil, a 
preheater and separate lines for the WVO. This runs around $1K and 
is a much larger commitment. You do have the option of running 
essentially free WVO with this version.

With regard to the choice of vehicles -- I chose a clean MB 
turbodiesel with 180K and paid $6K for the car. I put another $2K 
into it and was planning on putting another $1K into the 
suspension (Bilsteins, sway bars) but sold the car first. Older 
MBs will probably run forever, but they typically need some work 
when you buy them as the PO may well have put off some 
maintenance. Not to dissimilar from buying an older Audi...

The MB is a great car, but it's awfully dated as compared to same 
year Audis. Drove well, very comfortable, but just not up to the 
creature comforts of the Audi.

Also, it *SUCKED* in the snow, even with 4 fresh Nokian RSi snow 
tires. So I sold it and picked up another A6 quattro avant...

I did not look at VW TDIs. I bought just after the initial rush to 
older diesels last fall, and I'll bet there's something similar 
going on now. MB turbodiesels are difficult to find, and TDIs are 
*very* difficult to find. People are literally dragging rotting 
hulks out of fields and putting them up on ebay for $5K.

If I were going to buy and keep a diesel today, I'd get a Passat 
TDI. The MB is just too dated, and the W124 series is the last of 
the great MBs. The later ones have significant quality problems - 
shock mounts rusting through, all sorts of rust and paint issues, 
overall quality problems. Nice cars, but really problematic.

Or you could wait a year or two and buy one of the new clean 
diesels from VW or Audi. In 2 or 3 years, I'll be interested in a 
tdi quattro from Audi...they have some awesome engines in Europe 
that will be here soon...

Lee
'99 A6 quattro avant
'96 A6 quattro avant
'95 A6 quattro avant

Mohammed wrote:

> Lately, I've been mulling over the idea of getting a
> diesel something.  I've been leaning towards some sort
> of 90's VW TDI or an 80's Mercedes.  I think I can get
> something decent under 200k miles for less than $5k. Any 
> preference for either the TDI or the Mercedes?
> 
> My ultimate goal is to do a bio-diesel conversion.  If
> anyone has been down this road and wants to share info
> it would be very much appreciated.
> 
> Looks like you can convert an 80's Mercedes to
> bio-diesel for under $1k (rubber fuel lines-to-all
> steel) and they can be had for $3k or so.  Anyway,
> lots of good info on the net about this, but just
> wanted to see if someone here has gone down this
> route.
> 
> The motivation for this move is obvious; over $3/gal
> for premium for my A4, but the Audi stays.
>