New MPG numbers
 

In this day and age with diesel being so expensive it's imperative to squeeze as many miles per gallon possible. I decided to do a few modifications to increase my fuel efficiency and INOP it was totally worth it. These are the mods I have done to date....

1. Fitch Fuel Catalyst
2. Flex-a-Lite Syclone 14" fan w/ VSC speed controller
3. K&N air filter
4. Bosio nozzles installed and pop tested

I recently took a highway trip and yielded 36 MPG. The biggest difference was the installation of the Bosio nozzles, but the other mods have helped. My car runs great and in my opinion the money spent was well worth it.

The first two do little to help MPG, the K&N filter does nothing but pass dirt, the 4th is way past due maintenance on most every MB diesel. It looks like you got everything running closer to what it should be.

A better change to raise MPG would be to swap that 3.69 rear end for a 3.46 ratio. Advance the timing to 26-28*BTDC and get the cam back in time with the crank. Swap in the larger turbodiesel radiator and your electric fan will come on even less.

larger turbodiesel radiator?


As for gas mileage on my sd I removed the condenser, ac compressor, and receiver dryer when I did the motor swap to save weight and increase cooling efficiency. If your trying to get that fan to run less I suggest you remove the condenser if you don't use it.

Yes. Its wider, thicker and has many more core tubes spaced closer together.

is that the radiator that has a separate pressure tank with the cap off on the side and not on top of the radiator. if so I changed from the cap on radiator to the thicker and slightly more narrow one with the expansion tank and it makes quite a bit of difference in cooling.

yes.

Its not something I would do on a stock 240d though. They run so cool that the fan probably seldom runs anyway. If you are going very fast the forward movement of the car will probably to all the cooling needed.

If you do a lot of town driving it might be worthwhile, but otherwise I probably wouldnt do it unless the rad needed changing anyway.

Tom W

Both of my 123 diesels gained about 2 mpg by switching tire brands. Both had Bridgestone before, I forget the exact model number. The Bridgestones gave kind of a hard ride, and eventually developed some funny wear patterns that rotating wouldn't fix. Switched to Michelin Harmony's. MPG went up immediately, plus the ride is better. The 300D now has about 55k on the Michelins and will need new ones in a year or so. MPG has gradually increased by about another 2 MPG on the 300D. It finally dawned on me that it might be due to the tread wear (less rolling resistance). I bet the MPG goes down by a couple MPG when it gets new Tires with full tread depth.

Keep the K&N filter well oiled and you should be fine. I also run a K&N, but mine has a outer foam element that wraps the K&N to help keep it saturated! They don't nearly pass the dirt claimed unless neglected.;)