Dyno questions

Joined
Aug 26, 2010
Messages
8,216
Your maths needs work. Serious work.
On that chart you quote
29,700 is not 80% of 48,000 ??
And thats ethanol compared to gasoline.
Thats only ~60%.

Methanol has a stoichiometric ratio of about 6.5:1, and ethanol is about 9:1 to 10:1 so is much closer to petrol/gasoline as a fuel.

If you'd bothered to look at the data set I linked to, which shows methanol, ethanol and gasoline all on the same chart,
then methanol is almost neatly half the energy of gasoline.

Explosives factories, tubes of gunpowder ????
We seem to have diverged here somewhat.
Methanol is synthesized from hydrocarbons, although technically is termed an alcohol.
Nitro fuel isn't normally associated with petrol burning engines, but is in methanol fuelled engines ??
 
Joined
Jun 30, 2012
Messages
9,488
Country flag
Rohan, you are simply being perverse as ever. My comment about using nitromethane was made in relation to toluene/methanol blends. Methanol is not classified as a hydrocarbon fuel, it is an alcohol. Mixing nitromethane with hydrocarbon fuels (no hydroxyl groups) is dangerous. Babbling on about stochiometry proves nothing when there is a high latent heat of vaporisation involved. In any case, in many hydrocarbon fuels the combustion reactions of the various components probably compete, some give exothermic reactions and some give endothermic reactions at various stages in the process ?

'Which came first, the chicken or the egg ?' :

https://sites.google.com/site/hoyatherm ... ichiometry

http://au.search.yahoo.com/search?p=bom ... alorimeter

I would say one thing very clearly - BP JA is the best racing fuel that I have ever used.
 
Joined
Aug 26, 2010
Messages
8,216
You seem to be throwing red herrings and bad info left, right and centre...

Is this a planned strategy, or forgetfullness....

Just what is BP JA ?
It doesn't even come up in BPs Product Search
http://www.bp.com/business/iframe.do?ca ... Id=7070696

Methanol does.

http://www.bp.com/business/sectiongener ... Id=7070720

"BP Methanol
This is the only readily available fuel that produces any significant increase in power over petrol.
It may need up to 3 times the flow rate of petrol. Methanol may attack certain conventional fuels system components.
Many boat and car racing regulations prevent the use of this fuel. "

In conjunction with higher compression, maybe, they have ommitted to mention.... ??
 
Joined
Jun 30, 2012
Messages
9,488
Country flag
BP JA was a blend of 50% methanol, 50% Benzene with acetone added to facilitate blending. It hasn't been sold since the early 70s due to the toxicity of benzene. ( BP JB used t o be 40% benzene, 60% methanol). Your 'red herrings' are proof of your ignorance , both of the links I posted are relevant to this discussion. You need to learn some physical chemistry.
 
Joined
Aug 26, 2010
Messages
8,216
If, as you claim, methanol had 80% of the power of petrol, and BP says you need to burn up to 3 times the amount, then that would give over double the power.
That simply doesn't add up..... ?
 
Joined
Jun 30, 2012
Messages
9,488
Country flag
Not 'power', calorific value - energy content per unit volume. Common petrol contains much more e nergy for a given volume. HOwever the high latent heat of vaporisation means much more air is sucken in needing more fuel, wirh further cools the incoming charge , and so on. My point is that you don't need 100% methanol to ge t t he supercharging effect, and it's better to use a blend of a high energy content fuel with the high late nt heat of vaprisa tion material, to get more of it into the motor.

Found this interesting, but I couldn't find a decent link to Maserati fuel, also Mercedes use d t he benzene/methanol blends . :
http://www.megamanual.com/begintuning.htm
 
Joined
Jul 8, 2011
Messages
2,668
Country flag
..........................................Mass basis
..........................................Energy Ratio
kg/m3.....Item.........Mj/kg ......Compared to gasoline
737........Gasoline......45.8 ..................100%
789........Ethanol.......29.7.....................65%
791........Methanol.....22.7.....................50%
 
Joined
Jul 25, 2010
Messages
4,942
Country flag
'Which came first, the chicken or the egg ?' :


The EGG PLANT ! :wink:

Tolulene , in the model aircraft , is used for a RANGE IMPROVER .
Class B Team Race , 5cc engines , about 1/2 Hp. has a one ounce
fuel tank limit . Fuel could be 20 % oil , Nitro(methane) & Tolulene ,
thus 40 % methanol .

The Nitro produces tourque , and prefers a rich mixture to avoid melting things . the team racers DONT get a Rich Mixture They run a small intake , in the trade off off spped for laps ( Control Line ) . About 3/16 i9n. bore , running 'suction '.
The same engine would use a 9 mm bore intake , running a pressurised or ' bladder ' tank , which is akin to fuel injection .

the trade of is( was ) a airspeed of say 110 mph , and a 70 lap range , 1 stop 140 lap race . Without the tolulene theyed be 2 stops at 115 - or 3 @ 120 mph , the deceleration & acceleration time plus refuel & restart time would useually be
more than the airseed advantage provided .

Outside of all that , theres a minute ' warm up ' then 30 sec. ' stand clear ' before the Race Start .
Cool weather , theyre likely to bung the ducts with rag , to maintain tempreture for Race ' start ' ,
as a cold motor on tolulene likely wont start .

http://www.youtube.com/watch?v=MR7PNSQSxYQ

some fancy drivle on fancy fuel ingrediants : http://dkd.net/clmodels/glowfuel.html
 
Joined
Jun 30, 2012
Messages
9,488
Country flag
It's the result that counts. Any four stroke engine will be faster on methanol than petrol even iof the comp ratio is not raised ,especially if jetted to leaness to a level just before destruction. Two stroke engines are dramatically faster on methanol because the crankcases are part of the inlet tract. If using methanol, both types of motor will slow as they heat up - two strokes more so_On a 3Km road race track, with a two stroke you get two very fast laps and the rest are slower. So you don't warm the motor up before the race, and bore clearances are critical.
Matt, - Using nitro compounds in contact with hydrocarbons is bad practice and I wouldn't store that model aircraft fuel alongside my bike, or inside my house .
In a commando engine methanol is brilliant, however I've never raced anything other than a two stroke on petrol.
 
Joined
Jun 30, 2012
Messages
9,488
Country flag
About the calorific value of methanol. If it is anly half that of petrol more than twice the amount must be used because extra power must come from somewhere? Perhaps petrol fuelled engines always run rich to keep the engine temperature down, and the methanol can be run leaner to get the same combustion temperatures ? I think the main jets in a petrol fuelled Commando engine is about Amal 250, in my 850 motor on methanol they are Amal 670. And I am running an extra 4 degrees ignition advance. If you know what flow rates those numbers represent ...... ?
There is one thing about using methanol - it hides up the tuning errors. You can be a long way wrong in the rich direction, and still go relatively faster than on petrol.
 
Joined
Aug 26, 2010
Messages
8,216
You are obviously still floundering here.
The beauty of methanol is that it can be run RICH and even vastly rich, and still makes good power while keeeping engines cool enough to survive.
Why on earth would anyone run it lean - and heat the engine......

For it to make more than a token increase over petrol power though, the compression needs to be upped.
Seriously upped.
12:1 or even 14:1 Loves it !
(if your engine will do it, some can't physically cram that much piston in there, or shave the head enough.

Its methanols' resistance to detonation that makes this possible.
While keeping the engine cool.
THATS where the real power comes from.
You have obviously not explored this aspect in your Commando engine ?
 
Joined
Jul 25, 2010
Messages
4,942
Country flag
Heres a better one ; http://www.geistware.com/rcmodeling/glo ... istics.htm , with tecnical things , Like B.T.U.s .

One should be wary of inhalation & saturation with some of these substaces , due to there carcenogenic characteristics .
The more tecnical site is no more as is its owner whom suffered such conditions from such substances .

So wearing latex ? gloves & standing UPWIND when mixing , may further your longevity , substance & wellness .

no point in emulateing gluee sniffers or substance abuses , inadvertantly or otherwise .
 
Joined
Jun 30, 2012
Messages
9,488
Country flag
'Its methanols' resistance to detonation that makes this possible.
While keeping the engine cool.
THATS where the real power comes from.
You have obviously not explored this aspect in your Commando engine ?'

This is rubbish Rohan. To get the most out of methanol, it is as difficult to tune as petrol. The inlet tract is the only area which really needs t o be cool - that's where the extra power comes from. It is possible to run much higher comp. ratios, however it is not essential. Methanol will give a large power increase at comp.ratios as low as 7 to 1. Heat build-up is a problem in petrol fuelled racing motors, however very few Australian races these days are over long distances. If they were you wouldn't use methanol anyway, because of the poor economy it offers.
I suggest you need to think about how the high latent heat of vaporisation works. In a carburettor the air movement physically vaporises the fuel. That action creates a requirement for heat which is removed from the incoming air, and the carburettor body. This means the charge becomes denser, and the air component increases creating a need for more fuel to get sensible combustion mixtures. It is a self-generating cycle with a limit, and you don't need 100% methanol present to get it.
Perhaps you should actually try using methanol fuel in a four stroke bike sometime, and find out for yourself what it does ?
Incidentally, increasing comp. ratios is often a futile exercise. High crown pistons tend to be heavier, and obstruct the flame front in the combustion chamber. In most cases it is an unecessary complication, and if your motor is 'top end', it makes it that much nastier. In two strokes it is a recipe for disaster, regardless of the fuel used. The highest comp ratio that my brother or myself have used is in his stroked 600cc Jawa speedway engine which is on 17 to 1 comp. However the motor is actually a racing motor, not some modified, fragile street motor like a commando engine. The commando engine is fast enough on methanol without doing the silly stuff. It actually amazes me just how good it is, and it hasn't exploded - yet.
 
Joined
Aug 26, 2010
Messages
8,216
It is becoming very evident here that you only have half a clue of this stuff, and only half a memory of what has been previously discussed here.
It is also obvious it is a waste of space discussing it any further.
 
Joined
Jun 30, 2012
Messages
9,488
Country flag
Rohan, go away and find out for yourself what actually works with a racing motorcycle. When you discover it, build a fast commando and come and join me on a race circuit. I've been doing this stuff for 54 years both on road race circuits and speedway with both four stroke and two stroke engines. My brother and I have almost come to blows over tuning for methanol, and it has cost us a bomb learning how to do it. He now wins every race he ever enters with his speedway sidecars . I think you have a real problem with motorcycles, you seem to have something to prove and no physical way of doing it. Why should I waste my time getting into discussions with you ?
 
Joined
Aug 26, 2010
Messages
8,216
For the benefit of other readers, this was in the catalog as
high compression piston - alcohol.

As you can see, bumps the compression up, quite considerably.
Turns a road bike into a near racer, in one easy lesson.
Other tuning tweaks - cams, carbs etc add to it...



Incidentally, this would go near into bolting into a Commando.
Not that it was intended for one.
 
Top