Sorry, but that was a very ignorant post. He didn't buy this diesel. You need to read what he said and what I said. Everything I said is correct and he can measure what I told him to. I didn't say anything about specific gravity.

The question here is not whether he can use the diesel or not. The question is how to find how much gas (a percent, for example) is in the fuel. I have already given the answer.

 

I know that flash point is a definitive measure of gasoline contamination. A low flash point is definately testable. send me a sample. diesel fuel usually has a flash point between 140 and 155. anything lower than 140 indicates gasoline contamination.

 

The problem is not that the fuel wil or will not burn but that the nozzle tips blew off. This can happen because of the different molecular size of diesel versus gasoline. Some of the nozzles in the high HP engines now use really small (Measured in microns) orifices for extra fine atomization of fuel for combustion. Gasoline can be too big to fit through the orifices and at the extream injection pressures used the nozzle tips blow off and things get ugly.

 

I know - I was inferring that if the test fuel won't ignite with an open flame, there's not enough gasoline blended in to damage the injector tips.

On the common rail engines, the fuel molecules flow through the injector nozzles at Mach numbers...

 

Actually, you should be able to use Shovelhead's numbers as those are the densities and not the specific gravity values.

The catch to using those numbes is that when you test the density of your mixture, you'll need to make sure that your sample temperature is also at 60F (15.5C), otherwise it will throw your calculations off.

And since it is a range specified for diesel, you can calcuate once for the low value and again for the high value to give yourself a percentage range for your sample.

Otherwise, if you have access to clean samples of gasoline and diesel, you can stabilize the temperature of all three samples then do the measurements. You won't be exact on the percentage since you don't have a sample of the exact diesel used in your blended sample, but you should get close.

 

Maybe, but he didn't say what the units were. We need to know the units and convert all measurements to the same units.

 

I knew I forgot something I wanted to put in that post.

The density values are:

Diesel fuel oil - 15C - 820-950 kg/cu.m
Gasoline - 60F - 737.22 kg/cu.m

So as drolex said, you'll need to take your measurements in the same units or convert these to the values you're using.