Overview

I'm creating this blog to document my E320 CDI Conversion. I hope this will help others in their conversion of this vehicle.

Some of the posts may be random now but I'll go back and edit/organize them later as I have time.

I've pretty much finished the conversion at this point (with the exception of testing and a valve leak problem). This is a brain dump right now before I forget everything:

Overall the 2005 E320 CDI is a very easy vehicle the convert. The reasons for this are numerous:

1) The E320 CDI has a series of plastic underpans that bolt to the bottom of the car - these basically shield the entire underbody of the car except the exhaust and drive axle. The result of this is that running hoses (3/8" I recommend) is pretty easy and completely concealed/protected/insulated simply by bolting the underbody panels back up.

2) The bottom part of the trunk that holds the spare tire is entirely plastic. This means it is EXTREMELY easy to cut/drill/patch/etc. Running hoses into/out of the trunk and sealing them up afterwards through this plastic body is exceptionally easy since it is easy to drill individual holes for each hose.

3) The spare tire well is a perfect spot for a tank. Unfortunately it has to be custom made because there is no commercially available tank on the market, but I had one made for $500. This was a 15 gallon tank and fit the spot exactly. $500 included the flush-mount fill port that they special ordered from Summit Racing. The reason you need a flush-mount fill port is so that you can maximize the height of the tank (maximizing the amount of fuel it can hold) without hitting the trunk base panel (more on this later).

4) The fuel pluming at the engine is very simple, unlike the 96-99 E300s. It consists of a diesel supply line which feeds the diesel fuel filter. From the diesel fuel filter it goes into a mechanical fuel pump (big black metal thing bolted to the head, looks like it's part of the engine almost). From there it is pressurized to common-rail pressure (very high) and distributed to the common rail system. There is a return from the mechanical fuel pump as well as the end of the common rail. These tee together and run right back to the tank in a return to tank system. There is no fuel fed back into the diesel filter, there are no crazy loops or random places the fuel is routed. Tank -> Filter -> High pressure pump -> Common rail -> Tank. SIMPLE.

5) The coolant system is relatively easy to tap into (I'll post pictures showing you where to do it).

6) With the simple relocation of a bracket (and not so simple griding off of the bracket's bolting spot) you have a nice flat easy to use spot to mount valves that is in an ideal location. It's very close to the diesel filter, common rail, and diesel supply/return hose locations.

7) Wiring up the controller is also relatively straightforward.