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Why can't we use deisel fuel in our high compression engines


olie05

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I started thinking about it, and shouldn't we be able to run diesel fuel in our engines as long as were running a ridiculously high compression setup? (13:1+) It seems that diesel fuel works like high octane gasoline... Correct me if I'm wrong, (I probably am cus I don't know the first thing about diesel fuels...) But I want to know why were not using diesle.

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You need at least 16:1 or 17:1 compression to generate enough heat to ignite the fuel. A spark will not ignite diesel. You would also have a hard time pumping diesel through the EFI system, it's very viscous compared to gasoline, and it would not vaporize once out of the injector.

 

Diesel fuel is nothing like high octane gasoline - it's basically a light oil, similar to kerosene or home heating oil. It's flammability is called "Cetane", the lower the number the more resistant it is to ignition, and has nothing to do with how controlled the burn is, or "Octane".

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Guest skittyscott

my cousin's excursion with the powerstroke is running a 24:1 comp ratio

 

sleeperz, home heating oil IS deisel fuel. it is also known as "off road" deisel fuel for use in tractors and other heavy equip. the only difference between home heating oil and deisel is that they dye home heating oil so they can tell the difference. it is also one of the reasons why all new deisel trucks come with a see through fuel filter housing. if you are caught driving on the road with the dyed fuel, you can face up to $1200 in fines. because home heating oil is tax free and deisel fuel is not....

i dont usually agree with breaking laws, but with gas prices so high right now, i would deff take my chances running $0.90/gal home heating oil in my truck instead of $2.00/gal deisel...

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Guest bastaad525

Heh... are there any alternatives like that that can be used in stead of regular gasoline????

 

 

Kind of a side question here, but related: Even with todays modern EFI, an N/A motor is pushing it's luck at anything much higher than 10.x:1 compression on pump gas, 11:1 tops, right? However, according to a couple car calculators I've found, a bone stock 280zxt motor, at, what... like 7.5:1 CR (sorry if I'm wrong on that) running 10psi of boost, actually equates to running 12.6:1... the same motor pushing say, 18psi, is actually running 16.6:1 CR!!!! Now, I know there's guys running 18psi or more on pump gas... how is that possible?? I dont think you could run an N/A engine with that kind of compression that's for sure!!

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my cousin's excursion with the powerstroke is running a 24:1 comp ratio

 

sleeperz' date=' home heating oil IS deisel fuel. it is also known as "off road" deisel fuel for use in tractors and other heavy equip. the only difference between home heating oil and deisel is that they dye home heating oil so they can tell the difference. it is also one of the reasons why all new deisel trucks come with a see through fuel filter housing. if you are caught driving on the road with the dyed fuel, you can face up to $1200 in fines. because home heating oil is tax free and deisel fuel is not....

i dont usually agree with breaking laws, but with gas prices so high right now, i would deff take my chances running $0.90/gal home heating oil in my truck instead of $2.00/gal deisel...[/quote']

 

I've heard that about the fuel tax thing. I'm doing a similar dodge right now - I converted my daily driver (a Benz 300D) to burn used fryer vegetable oil, free. The filtering brings the cost per gallon to about $0.10.

 

However, according to a couple car calculators I've found, a bone stock 280zxt motor, at, what... like 7.5:1 CR (sorry if I'm wrong on that) running 10psi of boost, actually equates to running 12.6:1... the same motor pushing say, 18psi, is actually running 16.6:1 CR!!!! Now, I know there's guys running 18psi or more on pump gas... how is that possible?? I dont think you could run an N/A engine with that kind of compression that's for sure!!

 

The comparison of turbo vs. compression is just an equivalence. If you were not running an intercooler, you would have the internal temperature rise associated with such a compression ratio, but with intercooling you get the air volume without the temperature rise, making MAD POWA YO!

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