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 :lol: 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?




Look ma I'm goana blow myself up :newburn:

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

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.

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 :)

Cool now I just want a street engine to do that too :evillol: 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

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).

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/901/901-spring00/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.

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.

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.

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.

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 :screwy: 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.

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.

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.

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.

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. :evillol:

Sorry to burst your bubble kid, but your not going to think of anything that hasnt been done before just by using a differnt fuel or changing a minor detail.

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.


By mixing a low octaine and a high octaine fuel you do raise your avrage octain rating of the low grade fuel which raises your pre-ignition temps, which is exactly what I want. The mixing of two liquids that do not react with each other on the molecular leval will result in a mixture that has the properties of both in proportion to the percentage of which they were mixed, me and my chemestery teacher had it out as to any exceptions to this rule, it applies to all liquids, and vapors too I think.

Sorry to burst your bubble kid, but your not going to think of anything that hasnt been done before just by using a differnt fuel or changing a minor detail.

You are not busting any bubble kid I know it has been done before. I am not trying to break any new ground now if you have somthing to contribute to this dicussion please say it, if all you are going to do is talk $hit go away the internet is full of chumps like and we don't need one here. Go play on a porn site or somthing.

BTW how is your worlds largest vibrator coming LOL :lol: :evillol: :loser:

Your problems are going to lie in getting your a/f ration right and big problems with internal engine corrosion.

By the way, the vibrator thread was an inside joke- that you obviously did not understand.

Your problems are going to lie in getting your a/f ration right and big problems with internal engine corrosion.

By the way, the vibrator thread was an inside joke- that you obviously did not understand.

I don't think anyone understood, I did not see anyone laughing, at leased not with you LOL. Ok I am not one for petty fudes lets end this now and get back to the topic if I want to blow up an engine being stupid it's no skin off your back right? So lets just stick to the facts OK.

Do I have to close another thread? :grinno: Don't make me stop this car! Let's keep to the topic. Flames are for PMs. :grinyes:

Kachok25, your question is valid, but SilentChamber and the others are correct, too. Its probably been done, but the hundreds of pitfalls associated with it make it unfeasible.

So, back to the original engineering aspect of it, let's find the actual octane rating of Nitro and then do some math. No problem bench racing it and using new information to expand your knowledge, but let's stay realistic. Its not going to really work on the street.

I have seen staged injectors firing Methanol for high boost situations. A guy kept his 10.2:1 in his NSX and used two VATN aerochargers for about 10 psi. In order to keep it in one piece he piggybacked a simple injector computer and six nozzles to start laying on the alcohol when boost hit 4 psi or so.

That is really cool, all I needed was a piggyback ECU, six injectors,a small tank , and a fuelpump. That would be one of the best mods doller for doller around if you figure that alcohol can handle about 15psi more boost than 92 oct gas. Or about 7psi more with an even amount of both at full boost, that would allow about up to one bar on a high CR engine! How much would an intall like that run? I imagine it would require some fine tuning at the dyno though. Was there any other special mods that he had to do to optimaze the alcohol injection setup?

His install was over $10k if I remember correctly. It requires a completely separate dedicated fuel system, including tank, lines, sensors, computer, injectors, welding modifications to the intake, etc. All of the issues of EFI times two.

Other than that its basically figuring out the math and making a base map for the alky.

I think I could do that install for way cheeper than that I have seen complete fuel injector conversions including manifold for 2k. But I guess that is assuming that I do all my custom fabracation and fine tuing by meself. I wounder if anybody sells aftermarket kits for just this purpose.

Actualy now that I think about it I could probably attach a high flow nosle onto a water injection system ($500), it is boost actuated, now I just need to find a way to make it flow enough (some of them run 150psi), I seem to forget my forumula how much alcohol per minute would I need to sustain 100hp?
Update: Cooling mist makes a twin nosle kit with 150psi of pressure, their nosels are rated for up to 18gph so assuming that the pump can keep up with twins I could flow 36gph how much HP could I support with that? I am not sure one pump can keep up but I could intsall a second pump I just don't know if I can make it run off the same computer. It would cost me around $400 with twin pumps. Is there somthing that I am missing here or is this a relativly safe idea?

You could guess, but you'll be incredibly rich under low boost and incredibly lean under tall boost. You can't just inject massive quantities or wait for a pump to build pressure. That half a second could melt pistons.

You need the whole thing; computer, fuel map, boost-referenced pressure regulator, MAP sensor, the works. It has to be spot on for all conditions, not just a flood that hits the middle.

You could guess, but you'll be incredibly rich under low boost and incredibly lean under tall boost. You can't just inject massive quantities or wait for a pump to build pressure. That half a second could melt pistons.

You need the whole thing; computer, fuel map, boost-referenced pressure regulator, MAP sensor, the works. It has to be spot on for all conditions, not just a flood that hits the middle.

Oh no they claim that it is completly variable, it is a computer controled (check out the vari-cool computer control) sytem complete with pressure sensor, it is not a one speed setup. Besides even if it did take a half a sec to presurize (which it is supposed to be instant) while the turbos were spooling up the ECU could be programed to give it a little extra gas to compensate. By time the turbos reach full boost it could already have the alcohol flowing. You gatta remember this system was designed for high boost aplacations. Here I'll give you the link and then tell me if you think thei system is too flimsey for reliable use http://www.coolingmist.com/categories.aspx?action=set&res=1280
If I did go with the whole fuel injection system could I use the regular sensors and use an ECU with water/alke injection already calabrated into it? I know they make them. Oh BTW I would not be using this system much just for the occasinal trip to the track so running a little rich would not be a prob. And do you know how much alcohol I would need to run to make an extra 100hp? Would 18lbs an hour be a good enough flow rate. If not the pump is rated for 1.5 GPM I would think that would easly be enough for almost any applacation.

Duh my bad they go up to 18gal per hou not 18lbs per hour. Two of those would accamadate just about any injection needs I have:) They claim it is instant, and that the computer is programable with 10 fixed algorithms which is as accurate as I would need on a 1/4 mile run I think. Would there be any downsides to using this as opposed to a custom piggyback controled EFI system? Oh and one more thing would the EFI have to be built for methonol? I know parts built for gas don't like it much.

methanol eats away at rubber so you'd have to raplace anything with rubber.

methanol eats away at rubber so you'd have to raplace anything with rubber.
I know I am planning on replacing anything rubber in the system, but I don't think that is going to be a prob since water injection systems are designed to have alcohol in them anyway. But if I can find a stronger anti-detonante stronger than methonol that I can readly get I would gladly use it insted, I know I can get 116 octaine with toluine and 126 octaine with methonol. Now I am trying to find the octaine rating of karosine, diesel, and nitro methane. I would also like to know what kinds of whiches brews they used back in the turbo F1 days that allowd them to get 1,100hp out of a 1.5L engine I know they were primarly toluiine but what else made them that tough I don't know, because they had to be over 116 oct.

Well I still have not found the octaine rating of nitromethane but I do know that it is higher than methonol since it reportedly has a less tendency to knock at lower concentraitions of the 126 octaine fuel. It is supposedly so slow burning that it cannot completly burn inside the combustion chamber of a top fuel dragster before the exaust valve opens again! Hence the flames from their exaust. I am just guessing here but I think diesel burns faster than that. I am still woundering how much octaine I could add to pump gas by mixing it with this stuff in the intake runners. I'll keep yall posted as to any other cool facts that I find.

OK here is another site that is informative yet frustrrating. http://www.pricechemical.com/default.htm it says that mixing in 1/2% of nitromethane with pump gas will allow you to run a 14:1 CR!!! Yikes that stuff is potnet! if memory serves it would take about 100oct racing gas to handle that kind of compression, and if 1/2% nitromethane can raise 92oct to 100oct that would make it the most potent fuel addative on earth to my knowlage. If this is true following the principal that all mixtures react in proportion to the liquids in them that would give nitromethane an octaine rating of over 1600 if it brings the gas to 100oct and 1200 if it only gets it to 98oct. These numbers seem unreal and I need to do some more reserch but it looks promising. Nitromethane does not mix with gas without an addative and nitoromethane cannot be used in high concentration without having to remap your ECU since it burns at such low AF ratios compared with gas. It does mix well with alcohol though. There is also an oil addative that goes in your gas that also slows the combustion on this site, I wounder how close that is to my idea of using diesel to slow the combustion, since diesel is also an oil fuel. I just need to find a way to suspend it in gas.

OK one downside found, apparently when nitromethane burns it creates several funky acidic fumes that break down your oil, I have only heard about this on one site and it might be here say but since they are not selling anything I am inclined to beleve them over someone that is.

Update: OK I am now reading from another source that Nitomethane drasticly reduces the octaine rating of your gas I don't know what to beleve here sombody saying that it is better than methonol, and another site saying that it is worthless and dangerous, all I know is that the more i read the more confused I become so if anybody has any experence with this stuff please tell me what you know but I am going to quit reading about it online because it is giving me a headache! Does slower burning mean more knock resistant? If it is slower burning how can it be prone to exploding permaturly in the cylinder? If it is more prone to detonation then why do companies but it in commercial octaine boosters? And Summit racing defines it as an extreamly high octaine fuel used in top fuel dragsters.
I have found some cool hydrocarbons that would make intresting fuel addatives though
RON MON
cyclopentane 141 : 141
toluene 124 : 112
meta-xylene 162 : 124
para-xylene 155 : 126
3-ethyltoluene 162 : 138
1,3,5-trimethylbenzene 170 : 136
2-methylbutene-2 176 : 140
1-methylcyclopentene 184 : 146
1,3 cyclopentadiene 218 : 149
dicyclopentadiene 229 : 167
2-methylbutene-2 176* (113) 141*
http://www.faqs.org/faqs/autos/gasoline-faq/part1/

Have you had a search of this sub forum?

There is a really good thread hiding in here somewhere about running nitromethane, and the hows and whys of when it will and won't work.

Ok thanks

Kachok, looks like you're getting close to an answer. I just turned up a lead on some EPA and DOT regulations concerning nitromethane. Since its so volatile, using it on the road is a federal felony :( Up to 15 years in jail :D Basically you'd be transporting enough of a volatile gas to require a permit, and be transporting it without a commercial hazmat license in a non-approved container.

Methanol is still illegal on the road, but just for EPA reasons, not because its DOT-prohibited.

The other fuels you mention like diesel will cut down on power. Injecting diesel in a fine enough mist requires thousands of psi. I think my powerstroke operates between 1800 and 2500 psi. Then, without the intense heat available from the extra compression it doesn't burn well.

Kerosene would have very similar qualities to diesel, heating oil, and jet fuel, so they can probably be ruled out.

Another thing is that burn rate and octane aren't necessarily related. There are measurable differences in flame speed, but it shouldn't be used as a determining factor. Diesel fuel burns very slowly, but its octane equivalent is (from what I understand) lower than gasoline. Think of octane rating as how much energy it requires to get it burning, or in the textbook, delta +H or activation energy. http://www.gcsechemistry.com/rc23.htm

Higher octane ratings raise the peak of that curve in the above diagram so that it requires more energy to start. The activation energy is supposed to come from the spark, but if that curve's peak is too low it gets enough energy from surrounding sources that it ignites itself.

You'll want to select a burn rate that is nearly the same or faster. That will let you set the timing curve more conservatively and ensure that all of the additional fuel is spent in time for the exhaust valve to open. Choosing diesel might limit your RPMs and lower the overall octane rating. Methanol is probably the best choice. Pretty quick to burn, higher octane, easy to vaporize, legal to transport. :)

Thanks for the imput, yea I finnaly found the octaine rating of diesel and it is 35-50octaine depending on its centaine grade, but karosione is the primary ingredent of alot of octaine boosters. If nitromethane is iligal haow can they put it in octaine boosters??? Maby it is only legal at cartain concentrations I would still like to evauate the clames of that company that say that 1/2% nitromethane mixed with primum gas can withstand 14:1 CR but I somehow doubt that (never trust a sales man) Oh I just found an intresting alcohol injection kit it caims that all you need other than the $500 kit is EGT meter, and a wideband O2 sensor and a stock WRX is ready for 24psi of boost! I found a guy online that owns one and he highly recomended it, but like always I am still skeptical and reserching. If you find anything else intresting let me know.
BTW the EPA does not have to know aabout my methonol injection, because the system that I saw actualy uses the winshild wiper tank, and even has colored methonol to make it look real :)

If nitromethane is iligal haow can they put it in octaine boosters??? Maby it is only legal at cartain concentrations

Exactly. As a non-hazmat CDL driver, I am allowed to carry up to 5 gallons of certain substances like alcohol, gasoline, lighter fluid, and paint thinner. I can carry something like 50 gallons of kero, diesel, or oil in an approved container. I can't carry any nitromethane since any quantity of it is illegal without a hazmat endorsement, but like fat in food products, if its under 2% they don't have to list it. If there is below a minimum of nitro in that fuel booster, its legal to transport. DOT calls it something like insignificant quantities.

Oh cool I'll remember that next time I am transporting drug LOL! Hey check out this system I was talking about and let me know what you think of it http://www.smcenterprises.com/subaru.htm this is kind of like what I was talking to you about earlier just without the advanced "vari-cool" computer system.