I've been messing around with Biodiesel for years. It's what my business is too.
It runs extremely well in older diesel vehicles, but anything 2007 or newer is going to be a struggle to run Biodiesel in high blends with. More details on that here:
Why 2007 & Newer ULSD Emission Vehicles Don't Like Biodiesel - Topic Powered by Social Strata
Ford & GM have announced plans to change the way their Diesel Particulate Filter Systems will self-clean starting in 2011 which will make running Biodiesel in higher blends MUCH easier. From 2007 through current though, if you run Biodiesel in high blends in diesel engines with the diesel particulate filters installed you risk diluting your engine oil with Biodiesel, which can cause all sorts of problems in the long run.
Also, pre-1995 diesel vehicles sometimes need to have their fuel hoses replaced with Viton hoses in order to work well with high blends of Biodiesel.
Biodiesel acts like a solvent and can break them down.
That said, barring the DPF issue, Biodiesel runs extremely well in diesel engines. I actually know the group at Mississippi State University and the work they're doing. That's cool that they're experimenting with the raw sewage now.
If you'd like to learn about Biodiesel in general, there's a great website out there called The Collaborative Biodiesel Tutorial:
Welcome - Collaborative Biodiesel Tutorial Website
I also have several tutorial video's on my website as well at Utah Biodiesel Supply.
Here's the direct link to them:
Learn How To Make Biodiesel With Our Biodiesel Tutorial Videos - Utah Biodiesel Supply
Now, about Mahindra & Biodiesel.
I called them and talked to them and out the gate they aren't going to recommend using ANY Biodiesel in the trucks.
I believe this is probably because they're using a diesel particulate filter system that regenerates INSIDE the cylinders (like most other diesels engine manufacturer's implemented in 2007). If that's the case, you can actually use Bio in them, but you'd have to change the engine oil a lot more frequently to avoid getting any oil dilution going on....or.....just rip out the Diesel Particulate Filter and install a DPF Delete Kit. However, my guess is those won't be available for Mahindra's for a very, very long time.
Also, I'm far from a granola head either. I'm just a Biodiesel nut.
Here's my website:
Utah Biodiesel Supply - Biodiesel Homebrewing Supplies, Equipment, Processors and Information
I'm hoping that Mahindra will recognize the importance of Biodiesel in the US market place and approve blends of Bio in their engines soon, but for now, the "official corporate answer" from GV was "No. They won't be able to use Biodiesel".
-Graydon