Mileage... - PeachParts Mercedes-Benz Forum

iandiam · #1 03-28-2009, 08:38 AM

I'm curious...

By my calculations (and by those of the log book of the previous owner[s],) my 83 SD is getting 26-28 in town and up to 32 on the highway, at speeds of 45-65. Goes for WVO as well.

My compression is good, with little blow-by, first crank starter. A little smoke when cold, plenty of power, and 275k on the clock.

People have noted a 22/27 figure, roughly, and I'm pretty sure I have a stock rear end and so forth.

What gives? Is my SD an anomaly?!?1

vwbuge · #2 03-28-2009, 08:52 AM

Stock size wheels and tires?

LNGfish · #3 03-28-2009, 08:53 AM

You seem to be getting good mileage. They say 22 MPG is normal around town and if you get 30MPG hwy you are doing good. Do you want more than what you are getting?

iandiam · #4 03-28-2009, 08:55 AM

I'd say that what I'm getting is pretty damn good, no reason to ask for better. Just seems odd that it's so much higher than others.

I don't warm up very long though, only until the needle moves very slightly.

Stock 14" bundts and tires...

oldsinner111 · #5 03-28-2009, 09:01 AM

Thats what I get.My highest 37 mpg at average 75 mph was on wmo mix,more btus. But no more wmo until I get a high speed spinning filter.

iandiam · #6 03-28-2009, 09:13 AM

Quote:

Originally Posted by oldsinner111

Thats what I get.My highest 37 mpg at average 75 mph was on wmo mix,more btus. But no more wmo until I get a high speed spinning filter.

I use the dieselcraft OC20 mated to an oberdorfer N4000 gear pump. Over 3000mi between WO filter changes. 55 gallons in 4 hours at 130-150F. I'd like to put a small bypass spinner in the car for the lube oil, too.

Tymbrymi · #7 03-28-2009, 05:46 PM

Quote:

Originally Posted by iandiam

speeds of 45-65.

You've just answered your question!

iandiam · #8 03-28-2009, 06:05 PM

Quote:

Originally Posted by Tymbrymi

You've just answered your question!

I think you're right, plus the more BTU's thing with the veg.

If I could only find someone local to pop-test the Monark injectors with the 265 nozzles I pulled from the parts car I could swap them in...

oldsinner111 · #9 03-28-2009, 07:16 PM

No I was talking using waste motor and trans oils,they have higher btus.
But the carbon in motor oils is why i stopped using it.It might be like fine lapping compound in the injectors.
I use it now with diesel to heat the home.I buy my centif. wvo from a vendor 165 gals. a load.

#10 03-28-2009, 07:25 PM

Quote:

Originally Posted by iandiam

I think you're right, plus the more BTU's thing with the veg.

Other way around, Diesel has higher BTU.

probear · #11 03-28-2009, 07:34 PM

Quote:

Originally Posted by ForcedInduction

Other way around, Diesel has higher BTU.

Yup, FI is exactly right. #2 contains 140,000 BTU per gallon while VO or Bio-Diesel contains only 130,000 BTU per gallon.

Also, for your reading pleasure, #2 usually has a cetane rating between 45 and 50, Bio-Diesel is usually between 50 and 60 and Vegetable oil is 35 to 45. That is why the timing should be slightly retarded when running B100 versus #2.

Source

Jeremy5848 · #12 03-28-2009, 08:07 PM

Those mpg numbers are suspiciously good. Have you measured your odometer error with GPS over a significant number of miles, say 100, driven at one time and in a more or less straight line?

iandiam · #13 03-29-2009, 07:31 AM

Quote:

Originally Posted by Jeremy5848

Those mpg numbers are suspiciously good. Have you measured your odometer error with GPS over a significant number of miles, say 100, driven at one time and in a more or less straight line?

It matches with the mile markers on my local expressway. No GPS, I use the antiquated "maps."

iandiam · #14 03-29-2009, 07:36 AM

Quote:

Originally Posted by probear

Yup, FI is exactly right. #2 contains 140,000 BTU per gallon while VO or Bio-Diesel contains only 130,000 BTU per gallon.

Also, for your reading pleasure, #2 usually has a cetane rating between 45 and 50, Bio-Diesel is usually between 50 and 60 and Vegetable oil is 35 to 45. That is why the timing should be slightly retarded when running B100 versus #2.

Source

Good info, thanks,

Where does this fit in, though:

"'HOW WILL IT AFFECT THE POWER AND FUEL ECONOMY OF EXISTING EQUIPMENT?'

Under typical operating conditions, there should be no noticeable impact on overall power using ULSD fuel. Fuel economy may be reduced slightly because the process that removes sulfur also can reduce the energy content of the fuel."

Taken from http://fleetowner.com/mag/fleet_abcs_ulsd/ What is the mark of energy content to which they are referring?