Originally Posted by Green Dragon

Here you guys go. Here's 30 mpg. The first part is a spirited entry on the interstate. The second part I made the video continuous to prove a point. Sorry, its a bit long, but watch the whole thing. I engaged auto bahn mode at the end. I also had my Thule Roof rack on....dought!

The best I have ever gotten was 34.5 mpg on a trip for a consistent 200 miles. I had 4.10 diffs and shark injector and exhaust work. My goal is at least 40 mpg and a range of 999. I would like the most efficient e53 X5 in the world title...... the edrive F15 will have me beat. For now. I tune my cars for performance, and efficiency is a welcomed consequence.

Hand calculated mileage is very close to my obc, so I use it. +/- 0.86 I do run my own blend of fuel additives, however, this is 91 octane non-ethanol, with a few ounces of Lucus upper cyclinder lube only. Nothing special.

I'm going to be running a Euro 2 tune for the MS43 DME with headers after Christmas. The other M54 based forums have reported an nice performance bump with no cel's for catless headers and SAP (Secondary Air Pump) deletion. This set-up can pass emissions, and I will explain how in a different thread. I will be putting high flow cats eventually as a responsible compromise.

https://youtu.be/scA4atX8M18