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Old 12-23-2005, 10:05 AM   #1
kachok25
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Octaine equivlent of Nitro Methane

In top fuel drag racing they run alot of boost in those big 500ci monsters, and I have heard the reason they can is because the Nitro methane is a very slow burning fuel does anyone know how it would compare to gasolines octaine scale? And how many BTUs is Nitro Mathane puttind out when it burns (assuming the typical 90/10 mix used in top fuel) I am just guesing here but it is prob alot more than gas Could a small amount of nitro methae be mixed with gasonile to increase it's knock resistance, and increase it's power? I know the fuel ECU would have to be re-maped for the extra air that nitro burns I think it is 4:1 compared with gasolins 13:1 optumum air to fuel ratio correct me if I am wrong on that. Can the avrage joe get access to nitro methane or is that pretty much off limits to everybody but top fuel teams?




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Old 12-23-2005, 10:42 AM   #2
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Re: Octaine equivlent of Nitro Methane

if im not mistaken, higher octane fuel has a lower btu count. octane is resistance to burn. the reason you can run higher boost or cylinder pressures with the higher octane fuel is that it ignites at higher temperatures than lower octane fuel. that way just the increased heat from the compression of the air fuel mixture wont ignite it
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Old 12-23-2005, 03:23 PM   #3
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Re: Re: Octaine equivlent of Nitro Methane

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Originally Posted by mazdatech177
if im not mistaken, higher octane fuel has a lower btu count. octane is resistance to burn. the reason you can run higher boost or cylinder pressures with the higher octane fuel is that it ignites at higher temperatures than lower octane fuel. that way just the increased heat from the compression of the air fuel mixture wont ignite it
LOL NO I think you are way off on that one, the octaine has nothing to do with BTU rating. Octaine is just a mesurment of a type of molicule in the gas, that takes a little longer to burn because it is such a long chain of hydrocarbons. Higher octaine just menas that you can put it under more pressure before it knocks. I think Nitro Methane has a higher BTU rating than gas and it is supposed to be VERY slow burning, hence they can cram 31psi into a top fuel dragster through a roots supercharger! Gas would already be darn near ignition at that point before the pistion started compressing it. Do you know how hot the air coming out the other end of that supercharger is??? It takes 700hp just to turn it! A roots supercharger is prob heating that air to 500+ degrees at 31psi with no intercooler! No gasoline on earth could take that to my knowlage.
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Old 12-23-2005, 04:45 PM   #4
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Re: Octaine equivlent of Nitro Methane

nitromethane is not off limints to anyone, just go to a hobby shop and ask for it. model airplane fuel is available in blends up to 50% nitromethane and it should to be available in 99% pure form for the people who perfered to blend their own fuel. the down side is the quantities will be small and the price will be high unless a bulk supplier is available (think gas pump). a little bit of model fuel in the grass mower's gasoline used to make it cut like crazy when the grass was high
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Old 12-23-2005, 05:35 PM   #5
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Cool now I just want a street engine to do that too Nitro methane is a potent fuel and if it desolves well in gas it sould make the perfecet street weapon, I'll just need to make the engien run a little richer to compensate for the nitro methanes insane AF ratios
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Old 12-23-2005, 05:39 PM   #6
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Re: Octaine equivlent of Nitro Methane

you may want to do some serious research before putting the stuff in your car. brigs and straton engines are cheap compared to a car's engine. mistakes here can be costly. nearly forgot, nitromethane is a great solvent, it disolves paint, super glue, and probably rubber. methanol is corrosive. take that at face value, get a msds for the stuff to learn more (or contradict me).
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Old 12-23-2005, 06:28 PM   #7
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Re: Octaine equivlent of Nitro Methane

your question piqued my curiosity (along with my recent reinvolvement in flying models) so i did some digging around and found this:

http://www.chem.wisc.edu/courses/901...pdb/nitro.html

if the vehicle that you are planning to fuel with nitromethane is catylist equiped then do not, under any circumstances, put any nitromethane in the fuel. here is the deal, catyletic converters (and some O2 sensors) contain paltinum, which is soulable in aquariga (50% mixture of sulphuric acid and nitric acid), and nitric acid is a combustion byproduct of nitromethane. because of this i am quite sure that burning nitromethane in a catylist equiped vehicle will poision the catyletic converter. i appoligise for raining on your new found parade.
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Old 12-23-2005, 06:29 PM   #8
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Thaks for the info, yea I already know about methonols effect on rubber, I am going to have to use metal fuel lines. I'll be sure to give you some credit when I run my first 10second 1/4 mile or when I blow my motor to bits LOL.
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Old 12-23-2005, 06:59 PM   #9
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Re: Octaine equivlent of Nitro Methane

yes, yes..... but only if it makes a really big bang. on second thought, maybe i can forego the credit as long as you do not come hunting for me afterward.
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Old 12-23-2005, 07:02 PM   #10
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Re: Re: Re: Octaine equivlent of Nitro Methane

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Originally Posted by kachok25
LOL NO I think you are way off on that one, the octaine has nothing to do with BTU rating. Octaine is just a mesurment of a type of molicule in the gas, that takes a little longer to burn because it is such a long chain of hydrocarbons.
Actually he is spot on. The additives that go into gasoline (which we falsely call octane) have much fewer BTUs than gasoline. The net result is a lower BTU content of the fuel, but not by much.

Gasoline has a BTU content of about 18,400 per pound. Methanol is about 9500/lb. Nitromethane is 5000/lb, so actually nitromethane has about 70% less energy than gasoline.

But, Gasoline is typically burned at 12.8:1 for most power. Methanol is mixed at about 6.0:1 and Nitromethane a staggering 1.7:1.

All things "equal" using some equations I did for another project that used 567cfm, it works out like this at 6500 RPMs: A gasoline engine would have 53,176 BTUs released, a Methanol engine would have 67,545, and the Nitro engine would have 125,412 released.

Octane is an actual hydrocarbon; C8H18 like its kins, propane, heptane, butane, etc. Octane is very hydrophillic so fuel systems don't use it anymore. It used to be standard fare, but the fact that its highly volatile, has a high vapor pressure, and was determined to be a deadly carcinogen caused the switch to tetraethyl lead. Now we use other additives to achieve the octane rating which is an estimation of its knock preventative abilities. Its called the octane rating because of the namesake of the chemical it replaced.
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Old 12-23-2005, 07:24 PM   #11
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Don't worry if I blow somthing up I won't blame anybody but myself. I'll do it to just caus I am a little I would like to find somone else that has at leased tried it first even if they did blow up LOL Na for real I think this has real proformance potential, Maby I can set it up as a suplamental injector for a turbocharged system. could you imagine the kick that you would get from not only your turbo spooling up but a shot of nitro methane hitting the cylinder at the same time! Or even better using a spray of nitro methane to jumpstart your turbo that would all but eliminate lag times.
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Old 12-23-2005, 07:37 PM   #12
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Re: Re: Re: Re: Octaine equivlent of Nitro Methane

Quote:
Originally Posted by curtis73
Actually he is spot on. The additives that go into gasoline (which we falsely call octane) have much fewer BTUs than gasoline. The net result is a lower BTU content of the fuel, but not by much.

Gasoline has a BTU content of about 18,400 per pound. Methanol is about 9500/lb. Nitromethane is 5000/lb, so actually nitromethane has about 70% less energy than gasoline.

But, Gasoline is typically burned at 12.8:1 for most power. Methanol is mixed at about 6.0:1 and Nitromethane a staggering 1.7:1.

All things "equal" using some equations I did for another project that used 567cfm, it works out like this at 6500 RPMs: A gasoline engine would have 53,176 BTUs released, a Methanol engine would have 67,545, and the Nitro engine would have 125,412 released.

Octane is an actual hydrocarbon; C8H18 like its kins, propane, heptane, butane, etc. Octane is very hydrophillic so fuel systems don't use it anymore. It used to be standard fare, but the fact that its highly volatile, has a high vapor pressure, and was determined to be a deadly carcinogen caused the switch to tetraethyl lead. Now we use other additives to achieve the octane rating which is an estimation of its knock preventative abilities. Its called the octane rating because of the namesake of the chemical it replaced.
So how resistant is nitro methane to knocking? I am guessing that it is MUCH higher than gasoline, but what kind of octaine rating would it have?? I don't think that even 100 octaine racing fuel could stand up to 31 hot psi in a top fuel engine.
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Old 12-23-2005, 08:17 PM   #13
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Re: Octaine equivlent of Nitro Methane

I don't think you should use it on a road car, at leased not too often. the fumes are highly toxic so whatever you do don't idle using nitromethane. if you do set up a nitro system for your car, let us know with pics and videos.

I know nitro is alot more resistant to knock than gasoline because it withstands 30+psi in top fuel cars. If you just inject it into your car as well as gasoline though, it's not necessarily going to raise the octane rating of your fuel, if you have temps above the ignition temps of gasoline, the gas is going to ignite, then it's going to ignite the nitromethane. it might reduce knock a bit but unless you're running pure nitro, i don't think it will be very much. someone else probably knows alot more about this than me though, so take their word instead of mine.
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Old 12-23-2005, 08:51 PM   #14
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Re: Octaine equivlent of Nitro Methane

Another text book genious solving the worlds speed problems hard at work altering all facts and overstepping obsticals in order to boldly go where no man has gone before.
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Old 12-23-2005, 10:50 PM   #15
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Re: Re: Octaine equivlent of Nitro Methane

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Another text book genious solving the worlds speed problems hard at work altering all facts and overstepping obsticals in order to boldly go where no man has gone before.
With the exception of that altering the facts part, you are right on! Think outside the box.
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