[bondvagabond]

Okay, I'll ask my important question first, then those interested can read the rest of the post for more detail. So I wont bore everyone to tears.

Is adding the correct size turbo to an NA diesel good for mpg increase?
What model turbo should I use to optimise for mpg?
Bonus points if it is a common junkyard turbo, to keep it cheap
Guys are adding turbos to these motors to make crazy horse power, so not worried about blowing up the motor, but what should I set my max boost to to optimize for mpg?
What gauges would be good for tuning for optimum mpg, in addition to basic engine protection gauges like EGT, and Boost?
What additional info do you folks need from me to help you answer my questions? weight of car? horsepower of engine? peak torque rpm? rear end ratio? Let me know if you need any of this stuff and I will get it posted asap. Thanks again.

Well, for all you who are following the drama with my electric truck batteries being stolen on my other thread, I was trying to figure out a way to throw a geo metro motor in it instead since I didn't have a couple of grand for new batteries.

I found a guy, who hangs out on this forum (I'll let him out himself in case he wants to be incognito) through craigslist who wanted to trade his sweet mercedes diesel project and parts car for an electric vehicle project.

A match made in heaven, two happy campers flowering out of a manure pile of theft.

Anyway, on to the project. People on the internets are telling me that these W110 chassis mercedes with the OM621 2.0 diesel are getting between 30-35mpg stock. There have been worse starting points.

First I will baseline the vehicle, change fluids, filters, adjust valves and check compression,(checking compression is like checking the spark plugs for a diesel, it matters that much!) to make sure the basics are covered.

Then mercedes source sells a kit to upgrade the 60's style glow plugs to the 80's style which work a lot better apparently.

I will rebuild the injectors with monarch nozzles, supposedly an upgrade in mpg and power. I found some great plans on the net to build an injector tester out of a bottle jack and some other parts. Tuning the injectors for pattern and opening pressure should help everything else.

The pre-chambers on this engine are removable, so I think I will pull them and scrape all the carbon out that could impede the quality of the fuel squirt.

I could to rear wheel spats and underpan without wrecking the sweet style of the car

The car has a solid rear axle with leaf springs, so swapping to different axles from a different car to get other axle ratios should be doable.

Also, the same body was available with auto transmissions and gas engines, so maybe those came with different ratios and I could swap. The mercedes comes with a parts car that is gas engine manual transmission. I will check to see if it has different axle ratios.

On another thread on turbocharging gas engines for efficiency, it was stated that numerically dropping axle ratios was important for getting the most fuel economy out of adding a turbo.