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Old 11-29-2009, 11:40 PM   #19 (permalink)
Christ
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Quote:
Originally Posted by The Atomic Ass View Post
I don't suppose you have any data on the FE with straight diesel?
I don't, unfortunately, and I haven't had to do it enough to really have gotten any reputable data to begin with. TBH, I've only ever owned two cars that could use a SG, and I'm driving one of them now... the other is my wife's.

When I used to put diesel in my cars, I was like 16-18, always running out of fuel, etc. Right now, I don't think I'd be quite as willing to do it, but I'm not really sure why... probably because I have a gas station next door, and I actually pay attention to my fuel gauge now.

I've read in older Briggs and Stratton manuals that you could convert most of their gas only engines to diesel... they say to expect a power loss of about 20-30%, and an economy increase (run time on a metered tank at X load) of up to 30%, if that helps at all. I've never converted one, or tested the theory with a small engine, though.

I'll tell you what, though... I can give you a single tank reading when I pull the van off the road... I'll put 5 gallons of diesel in 15 of gas, fill the tank, and drive it out, then refill with gasoline. Its not accurate, but you've seen my average, so it'll be kinda obvious if there's a big increase that something worked.

Quote:
Originally Posted by tjts1 View Post
Does adding diesel fuel to gasoline in any proportion increase or decrease the overall octane rating for the fuel?
I dunno, actually... Diesel's knock rating is in Cetane, not Octane... I dunno how to measure Octane levels on my own, and don't have a test block to do it with, so I couldn't honestly say.

Cetane and Octane are "made up" numbers, which give you an idea of the chemical composition of the fuel... Cetane, at higher numbers, gives a higher chance of autoignition, which is desirable in those type engines.

Octane, on the other hand, measures the resistance to compression ignition, a completely different beast.

Cetane is an alkaline molecule that ignites under very low compression situations. It has a Cetane number of 100. The higher your oil fuel's cetane number, the lower compression is required to ignite it.



Read more: cetane number - Comparison to Octane Rating, Chemical Relavance, Measuring Cetane Number, See Also, External Links cetane number - Comparison to Octane Rating, Chemical Relavance, Measuring Cetane Number, See Also, External Links
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