When it rains it pours!
- Thread starter sicivicdude
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Look up using Nitro fuel for R/C cars, its 2-stroke and ive seen it used successfully in weed-eaters before. it just seems a bit easier get than what fuel you're thinking about running (idrk?)
Sounds like a really cool build. then again I do like anything fast enough to do something stupid on haha keep us updated to me it sounds like you got hoed a bit I woulda told the guy 200, 250 tops. I mean I could bought my buddie's 05 blaster that was blown up for $400 last year but couldent cause his dad sold it already but like you said 
Same stuff there. The rc cars run nitromethane. Same thing he plans to run. Same thing I am planning on running in the future. It can be done since the 2 stroke r/c cars love to drink some nitrometh, its just it hasnt been done often enough with quads and bikes to have all the tuning info at easy access.
Some interesting facts about nitromethane.
14.7 lbs. of air is required to burn 1 pound of gasoline, but only 1.7 lb. of air for 1 lb. of nitromethane. Since an engine’s cylinder can only contain a limited amount of air on each stroke, 8.7 times more nitromethane than gasoline can be burned in one stroke. Nitromethane, however, has a lower energy density: Gasoline provides about 42–44 MJ/kg whereas nitromethane provides only 11.3 MJ/kg. This analysis indicates that nitromethane generates about 2.3 times the power of gasoline when combined with a given amount of oxygen.
Nitromethane has a laminar combustion velocity of approx. 0.5 m/s, somewhat higher than gasoline, thus making it suitable for high speed engines. It also has a somewhat higher flame temperature of about 2,400 °C (4,352 °F). The high heat of vaporization of 0.56 MJ/kg together with the high fuel flow provides significant cooling of the incoming charge (about twice that of methanol), resulting in reasonably low temperatures.
Nitromethane is usually used with rich air/fuel mixtures because it provides power even in the absence of atmospheric oxygen. When rich air/fuel mixtures are used, hydrogen and carbon monoxide are two of the combustion products. These gases often ignite, sometimes spectacularly, as the normally very rich mixtures of the still burning fuel exits the exhaust ports. Very rich mixtures are necessary to reduce the temperature of combustion chamber hot parts in order to control pre-ignition and subsequent detonation. Operational details depend on the particular mixture and engine characteristics.
A small amount of hydrazine blended in nitromethane can increase the power output even further. With nitromethane, hydrazine forms an explosive salt that is again a monopropellant. This unstable mixture poses a severe safety hazard, and is forbidden for use in model aircraft fuels.
In model aircraft and car glow fuel, the primary ingredient is generally methanol with some nitromethane (0% to 65%, but rarely over 30% since nitromethane is expensive compared to methanol) and 10–20% lubricants (usually castor oil and/or synthetic oil). Even moderate amounts of nitromethane tend to increase the power created by the engine (as the limiting factor is often the air intake), making the engine easier to tune (adjust for the proper air/fuel ratio).
@uncagedshadow: Thanks for the informational blurb. I missed the "proper" AFR for pure nitromethane by a bit but I have *read* that there really isn't a proper AFR for pure nitromethane.... it's basically limited the the amount you can get into the cylinder. The richer it is, the more oxygen is present in that portion of the fuel and the more burns.
I know about the lack of available information about using this fuel.... I'm going blind.
I know about the lack of available information about using this fuel.... I'm going blind.
i have one of those r/c cars. that sure wouldn't be the way to get this gas. you pay like$30 a gallon for the cars. we just pay that because in those little cars a gallon will last like a year
Actually, nitromethane is about $100 a gallon. $30 a gallon for 25% nitromethane isn't a terrible price, about what it would cost to mix and R/C car fuel already has castor 2 stroke oil mixed in.
I may actually end up running R/C car nitro fuel in the 25% blend in this machine. I'm figuring about 600cc's of fuel for a 300ft pass not including ANY warmup time. I'll need about a half a gallon for a whole run LOL. Not going to be a very economical playtoy but should be an absolute blast while I'm at it.
Stay tuned. I'm doing a write-up on my crankshaft tonight....
I may actually end up running R/C car nitro fuel in the 25% blend in this machine. I'm figuring about 600cc's of fuel for a 300ft pass not including ANY warmup time. I'll need about a half a gallon for a whole run LOL. Not going to be a very economical playtoy but should be an absolute blast while I'm at it.
Stay tuned. I'm doing a write-up on my crankshaft tonight....
There are deals out there..... I got my yellow blaster in a parts bin for $50. It needed a top end to be fully functional but there are deals out there.
The extent of the damage this blaster engine had wasn't obvious from the outside either. The busted case was covered in grime and the guy was running it with the busted up clutch. I *thought* it only needed a top end to be 100%.
The extent of the damage this blaster engine had wasn't obvious from the outside either. The busted case was covered in grime and the guy was running it with the busted up clutch. I *thought* it only needed a top end to be 100%.
No problem civic... When you go searching for your fuel at say hobby shop or whereever, take a look at some different bottles and read the back of them. It is legal to sell nitro fuel for r/c cars with anywhere from 25-65 percent nitromethane. The rest is methanol and the oil additive. They also sell them at different oil mix ratios i beleive. As long as there is nitro present at 25% or greater then it can be labeled nitro fuel for use in r/c cars and r/c airplanes/helicopters.
I have nitro R/C equipment and have done quite a bit of homework on what the various blends of fuels and oil ratios are. I actually have some "airplane" nitro fuel here that is 10% nitromethane and 5% castor bean oil. I also have some 15% heli fuel with 7% oil. 5% oil is 19:1 mixture 7% is more like 14:1. I think I'm going to shoot for 25% nitro with 5% castor oil for my mixture.
The higher nitromethane ratios are for pregressively "hotter" tuned engines (misnomer, nitro runs cooler than methanol) like 1/10 on-road nitro cars. I have seen as high as 33% nitro in a hobby store never anything as high as 65%...
I think I'm going to be getting what I want out of this at about 25% nitro methane so I *should* be able to pick up that fuel at about any hobby store.
A quick update and an offer:
I got a crankshaft rebuilt a while back. My original intention was as a spare stock stroke crank but upon seeing the product, this idea grew.
First the pics, then the pitch!
We all know what a busted crankshaft looks like.... but here's a pic anyway!
Now the finished product:
Now for the pitch...... I contacted a crankshaft rebuilder about doing a sustainable but inexpensive crankshaft rebuilding service for the blaster forum.
Competitive Crankshafts out of California does crankshaft rebuilds on just about any 2 stroke you can think of. That ^^^^^^^^ crankshaft was rebuilt by them after I purchased a rod kit. I asked them how much they'd be willing to turn around blaster cranks for (regular everyday parts plus labor price). They agreed to press our crankshafts for $99 return shipping included. The process is as follows in case anyone is interested: send them en email and mention the "blaster forum" crank deal. Give them your name so they'll be on the lookout. Ship them your busted crank (USPS parcel post with delivery confirmation about $8) as long as the webs are in good shape. They press the assembly apart and clean the webs. Press a new rod kit back into the newly cleaned webs and mail it back to you in a medium flat rate Priority mail box. You pay them $99. As long as your crank webs are in good shape, you can save about $50 off the price of a new crankshaft and this is to book specs rebuilt using all new components.
The higher nitromethane ratios are for pregressively "hotter" tuned engines (misnomer, nitro runs cooler than methanol) like 1/10 on-road nitro cars. I have seen as high as 33% nitro in a hobby store never anything as high as 65%...
I think I'm going to be getting what I want out of this at about 25% nitro methane so I *should* be able to pick up that fuel at about any hobby store.
A quick update and an offer:
I got a crankshaft rebuilt a while back. My original intention was as a spare stock stroke crank but upon seeing the product, this idea grew.
First the pics, then the pitch!
We all know what a busted crankshaft looks like.... but here's a pic anyway!
Now the finished product:
Now for the pitch...... I contacted a crankshaft rebuilder about doing a sustainable but inexpensive crankshaft rebuilding service for the blaster forum.
Competitive Crankshafts out of California does crankshaft rebuilds on just about any 2 stroke you can think of. That ^^^^^^^^ crankshaft was rebuilt by them after I purchased a rod kit. I asked them how much they'd be willing to turn around blaster cranks for (regular everyday parts plus labor price). They agreed to press our crankshafts for $99 return shipping included. The process is as follows in case anyone is interested: send them en email and mention the "blaster forum" crank deal. Give them your name so they'll be on the lookout. Ship them your busted crank (USPS parcel post with delivery confirmation about $8) as long as the webs are in good shape. They press the assembly apart and clean the webs. Press a new rod kit back into the newly cleaned webs and mail it back to you in a medium flat rate Priority mail box. You pay them $99. As long as your crank webs are in good shape, you can save about $50 off the price of a new crankshaft and this is to book specs rebuilt using all new components.
That crank looks rather nice and 99$ is just about unbeatable. I happen to have a crank that needs a new rod and I was contemplating just putting her away for a stroker right now, but I might just go this route for the time being.
Now on to nitrometh. I am happy to see you do lots and lots of research(explains your vast knowledge). I also do massaive amounts of research on anything that comes into my crazy mind. The cooling properties of nitromethane are one very awseome effect that made me want to setup my blasty on it other than the fact you can get about 3 times the power output as gas with equal amounts of air. The 65% blends arent exactly sold in everyday hobby shops. Only reason I know of this blend is becasue a buddy of mine ordered some and ran it with great power results but not so great wear qualities, apparently it has quite a bit less oil mixed.
Now you shouldn't have too much trouble finding a 25% mix nitro fuel. That is what my buddy runs just about all the time. Gets it at our local hobby shop.
A very interesting but scary thing about nitromethane, is that it can burn even without the presence of oxygen. I.E. a monopropellant. Let me pull up the chemical formula for all the science buffs on the net.
Here we go --- 2 CH3NO2 → 2 CO + 2 H2O + H2 + N2
This could result in the engine running continuously until no more fuel gets introduced. I am confident this would only result if a high concentration of nitrometh was used(probably close to 100%, but not sure). I mean nitro r/c cars, helicopter, and airplanes are built to run this stuff and I have never heard of one going crazy. This most likely is a result of the fuel they use being, usually, 10-30% nitrometh, 5-10% castor or synthetic oil, and a varying amount of methanol added for some stability.
Now on to nitrometh. I am happy to see you do lots and lots of research(explains your vast knowledge). I also do massaive amounts of research on anything that comes into my crazy mind. The cooling properties of nitromethane are one very awseome effect that made me want to setup my blasty on it other than the fact you can get about 3 times the power output as gas with equal amounts of air. The 65% blends arent exactly sold in everyday hobby shops. Only reason I know of this blend is becasue a buddy of mine ordered some and ran it with great power results but not so great wear qualities, apparently it has quite a bit less oil mixed.
Now you shouldn't have too much trouble finding a 25% mix nitro fuel. That is what my buddy runs just about all the time. Gets it at our local hobby shop.
A very interesting but scary thing about nitromethane, is that it can burn even without the presence of oxygen. I.E. a monopropellant. Let me pull up the chemical formula for all the science buffs on the net.
Here we go --- 2 CH3NO2 → 2 CO + 2 H2O + H2 + N2
This could result in the engine running continuously until no more fuel gets introduced. I am confident this would only result if a high concentration of nitrometh was used(probably close to 100%, but not sure). I mean nitro r/c cars, helicopter, and airplanes are built to run this stuff and I have never heard of one going crazy. This most likely is a result of the fuel they use being, usually, 10-30% nitrometh, 5-10% castor or synthetic oil, and a varying amount of methanol added for some stability.
yeah, it's the pure nitromethane variant that will burn in the absence of atmospheric oxygen. Top fuel is limited to about 90% for this reason. The ability for it to "run-away" drops dramatically once less than 100% nitro is used because the methanol "dampens" the heat needed to produce a "free" hydrogen and carbon monoxide. At high levels (90%) some hydrogen does escape the combustion chamber and ignites open contact with air (which is actually the white ghostly flames shooting out of top fuel engines)
I'm not going to be near the mono-propellant area with 25%.
I'm not going to be near the mono-propellant area with 25%.
Ok thanks for clearing that up civic.
Question. Would it be possible to mix some, say, 93 octane pump gas with some pure nitrometh and have a feasible fuel?
I've never heard of this so I am wondering if it would mix, becasue it seems it would be way more economical to mix some nitro meth with pump gas to get the end fuel you want. Even say a 25% nitro to 75% pump gas would net some pretty awesome power gains. However easier it would be to buy some r/c nitro fuel and just run that, might be more cost effective to mix pure nitro with some gas, and then add you oil blend to whatever ratio you want.
Question. Would it be possible to mix some, say, 93 octane pump gas with some pure nitrometh and have a feasible fuel?
I've never heard of this so I am wondering if it would mix, becasue it seems it would be way more economical to mix some nitro meth with pump gas to get the end fuel you want. Even say a 25% nitro to 75% pump gas would net some pretty awesome power gains. However easier it would be to buy some r/c nitro fuel and just run that, might be more cost effective to mix pure nitro with some gas, and then add you oil blend to whatever ratio you want.
The problem with mixing and blending is the difference in densities, energy densities, flame front speeds, and stoich mixture rates.
Nitromethane doesn't actually blend, it just mixes for a little while and then it will fall back out of suspension
Engine design considerations are different (and somewhat conflicting) for top fuel and gasoline.
Nitromethane doesn't actually blend, it just mixes for a little while and then it will fall back out of suspension
Engine design considerations are different (and somewhat conflicting) for top fuel and gasoline.
I'm thinking about whipping the old plastic and purchasing a set of 12" slip rolls for bending cones I'll be making a wide fit in frame drag pipe. Probably come way out the right side and then tuck back in just ahead of the rear frame tube.
I found a nice one that's within my price range... A woodward fab WFSR12.
I'll be making a wide fit in frame drag pipe. Probably come way out the right side and then tuck back in just ahead of the rear frame tube. I found a nice one that's within my price range... A woodward fab WFSR12.
I WILL NOT have an OOF pipe for a "trail" machine (not that is will ever see a trail but I'm still calling it a trail bike) but I will hand roll cones into a monster drag pipe as long as it still tucks back into the frame before coming out the back of the machine.... perhaps a distinction without a difference but I will have the distinction...
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