Monthly Archives: December 2015

Two-Stroke Oil

With fuel prices a cheap as they’ve been (diesel across the street at the Four Winds Travel Center is currently $1.889), and Love’s continuing to charge a ~25% premium for B10 biodiesel, I decided to look into less expensive alternatives.

I have heard from many people that Cummins engines like a quart of TC-W3 ashless two-stroke oil mixed into a tank (32-35 gallons) of petrodiesel. The two-stroke oil improves the lubricity considerably and may even increase the cetane rating. And a gallon¬†of SuperTech¬†two-stroke oil is $12.88, making the per-tank cost $3.22. Loves’ price for B10 today is $2.289, a thirty-cent (or 21.3%) premium. Thus a tank of petro plus a quart of TC-W3 works out to $69.34; a tank of B10 is $80.12.

Bio is good, but is it that good?

Anyway, I found an unopened quart of TC-W2 (old stuff from chainsaws) in the garage and decided to fill up with plain petrodiesel at Murphy Express in Los Lunas after putting the quart of oil in the tank.

The engine seems to run hotter with the oil-and-diesel mix. Whether this is attributable to the TC-W2 oil itself, or just that petrodiesel has more BTUs per gallon than B10 does, I don’t know. But even in mid-teens temperatures, the truck warms up by the Isleta exit, whereas before it would take slightly longer.

EGTs seem higher, which squares with the fuel burning hotter, too. EGTs seem to be around 400 degrees minimum under load, a bit higher than usual.

And the fuel economy has improved as well. The lie-o-meter is saying I’m getting over 21 MPG at 65 MPH, whereas before it was about 1 MPG less. We’ll see what the hand-calculated numbers say on my next fill up.

It does seem to create more smoke in the exhaust. The bumper has quite a bit more soot on it than usual.