On Tue, 26 Feb 2013 14:31:18 -0800 (PST), jon_banquer
wrote:

On Feb 26, 2:06*pm, Ed Huntress wrote:
On Tue, 26 Feb 2013 14:02:10 -0800, wrote:
On Tue, 26 Feb 2013 15:26:19 -0500, Ed Huntress
wrote:

On Tue, 26 Feb 2013 11:52:10 -0800, wrote:

So I was wondering, from a post here about a bone stock engine running
nitro methane instead of gasoline, how much extra horsepower could a
stock engine produce just by changing fuels from gas to nitro? I'm
thinking that the engine won't run very well. Now, I'm sure that if
the compression was changed, and the carb re-jetted, and the cam
changed, things might work better. But if all you do is change fuels I
think there won't be much of an increase. This is of course in
response to gunner's assertion that he was clocked going 264 mph on a
bone stock Ninja motorcycle burning nitro methane fuel. I don't think
the motorcycle could develop enough power to push itself and someone
sitting on it to over 200 mph no matter what kind of fuel it was
burning.
ERic

At the time Gunner initially made this (absurd) claim, an all-out
lakes-modified Ninja did 231 at Bonneville. That was considered to be
the world record for Ninjas, although it wasn't a class record. Some
other make was slightly faster.

The 1000 cc *Honda that topped 270 was claimed to have 400 hp. That
doesn't sound unreasonable: the engine was built by Honda specifically
for this attempt. That must be very recent, because Gunner held the
world record for sit-on motorcycles until very recently. g!

That is, if Gunner had actually gone 264 when he said he did, that
would have been a world record at the time. The record for "sit-on"
motorcycles was broken by Al Lamb in 2012. It was 265 mph, and the
bike was another Honda.

As for running a stock engine with nitromethane; only if you want to
turn your engine into shrapnel. It is very weird stuff, behaving
differently with different percentage combinations of gasoline or
methanol. You may get lucky with small amounts, or, if the gasoline
sucks up the oxygen in the mix, you may blow your muffler into the
next county when the resulting hydrogen explodes in your exhaust pipe.
If you use much, you will blow up any of several parts of your engine.
It's strictly for people who know what they're doing. It also costs
too much to be practical. And if your engine is newer than, say, 1980,
forget it unless you're an electronics expert, too.

If you want a chemical jolt for more horsepower, go for nitrous oxide
("the bottle"). You'll find kits for it all over the Web. We used to
have an expert on it here (Bottle Bob) but I think he left.

With nitrous, your engine may actually hold together long enough for
you to get home. g
In the early 80s I found a radio control airplane store that sold
nitromethane for the engines in these model planes. It came in quart
bottles at different concentrations. So I used to buy the stuff and
run it in lawnmower engines. I would mill the heads until they would
just clear the valves to increase the compression some too. I was
amazed at how much better the lawnmowers would cut tall, thick grass.
Engine life was poor though. I never did try to run straight nitro. It
smelled good too.
Eric

Jeez, Eric, that's the only nitro-fueled lawnmower I've ever heard of.
Did you have to run behind it to keep up?

Regarding the model planes, yes, and I had to soup glow plug fuel with
an extra 10% nitro to start my model OS Wankel. That would mean about
20% nitro in total.

But a lawnmower? Jeez. Yeah, I'll *bet* engine life was poor. g

--
Ed Huntress

http://en.wikipedia.org/wiki/Glow_fuel

"Ingredients

Glow fuel is a mixture of methanol, nitromethane, and oil.

Methanol is the primary ingredient as it provides the bulk of the
fuel, and is needed as a solvent for the other ingredients. The
presence of methanol causes the glow plug found in model engines to
heat via a catalytic reaction with the platinum metal wire element
which glows in the presence of methanol vapor.

Nitromethane is added to the methanol to increase power and to make
the engine easier to tune. Typically glow fuel is about 0-30%
nitromethane. While higher concentrations can result in better engine
performance, usage of highly concentrated nitromethane is rare due to
its cost. Although a given amount of nitromethane contains less energy
than the same amount of methanol, it increases the amount of available
oxygen in the combustion chamber per every intake stroke, which allows
the engine to draw in more fuel while still maintaining a favorable
mixture setting. The increased amount of fuel entering the engine
increases power output, and also aids in cooling. For racing use, the
nitromethane content can be increased to the range of 30%-65%.

Nitromethane is often difficult to obtain in many countries, so in
these countries glow fuel typically has no nitromethane at all.

Lubrication

Most model engines require oil to be included with the fuel as a
lubricant since the engine has no independent oiling capability. Model
engine fuel is typically 8-22% oil, with the higher percentages run in
older design two-stroke glow engines that use bushings for the
crankshaft bearings. The most commonly used lubricants are castor oil
and synthetic oils, and many glow fuels include a mixture of the two.
The oils included in glow fuel generally are not burned by the engine,
and are expelled out the exhaust of the engine. This also helps the
engine dissipate heat, as the oil emitted is generally hot.

Four stroke model engines, since they are generally designed to be
simple powerplants while still incorporating the usual camshaft,
rocker arms and poppet valves of larger sized four stroke engines, are
generally meant to use glow ignition and their fuel. Often, the oil
percentage for four stroke glow fuel can be lowered from the 18-20%
figure used for some two-stroke engines, down to as low as a 12-15%
percentage per unit of blended glow fuel, but use of such low-
percentage lubricant fuel can also mandate the need for a small
percentage of castor oil in the mix to avoid having too little oil in
the mix, and also mandates setting the high-speed fuel mixture
carefully by using a handheld digital tachometer to check engine speed
to avoid over-leaning of the fuel mixture.

Glow engines generally have to be run slightly rich with a higher fuel/
air ratio than is ideal to keep the engine cool as the fuel going out
the exhaust also takes heat with it, and so vehicles with glow engines
generally get coated with lots of oil. Almost all the oil comes out
the exhaust, and some nitromethane and methanol as well (as it's not
all burned) requiring some cleaning when one is done using the model.

The nitromethane that exists in many glow fuel blends can cause
corrosion of metal parts in model engines, especially four-stroke
designs, due to the nitric acid residue formed from combustion of
nitromethane-content glow fuel, making the use of a so-called "after-
run oil" a common practice after a model flying session with a four-
stroke glow engine-powered model.

Glow fuel is not difficult to make, and so many modelers mix their own
to save money, but some of the ingredients are flammable and/or
explosive and so can be dangerous, especially in large quantities.
Most modelers buy their glow fuel premixed from such manufacturers
such as Byron, Blue Thunder, FHS Supply, Model Technics, Morgan,
Powermaster, Tornado, Wildcat, and many others.

"Typically glow fuel is about 0-30% nitromethane."

Yeah, standard old blue-can Cox was 10% nitro. It probably still is.
Cheaper stuff has 5% or less.

--
Ed Huntress