Switch from Pump to C-12
- Thread starter Txbigguy
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'00kx250spode
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- Oct 21, 2000
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I was able to make the only necessary jetting adjustment with the air screw. I had to turn mine in - making the slow circuit richer. The bike bogged terribly until I did this. After I adjusted the screw, it made a very noticeable difference in throttle response.
But note that having to make the slow circuit richer seems to be an exception to everyone else's experience. Go figure.
But note that having to make the slow circuit richer seems to be an exception to everyone else's experience. Go figure.
Having to lean the jetting across the board is the most common scenario when switching to C12.
For a non-oxyegenated fuel I really like C12.
Here are the specs for the two fuels mentioned.
VP C-12
Motor Octane:_____ 108 MON
Specific Gravity: ___.717 @ 60F
RVP: ______________7.3
Oxidation Stability (min.) 1440+
Distillation:
10% evap ________@131.0°F
50% evap ________@194.0°F
90% evap ________@228.0°F
E.P. _____________@233.3°F
Color: ____________Green
Lead: ____________4.23 g/gal
Torco Mach 110
Specific Gravity____.710
Pump Octain_______110
Distillation _________F
10% evaporation____@160°F
90% evaporation____@211°F
color______________purple
leaded ____________yes
end point___________246
Can anyone comment on theses fuels using the data I was able to get to tell me if one is better than another, and more importantly why? I'm trying to make some sense out of the fuels I use. This looks like it may be a good learning experience for me. Maybe someone else too. :)
Mike, where do you get the Torco fuel locally?
VP C-12
Motor Octane:_____ 108 MON
Specific Gravity: ___.717 @ 60F
RVP: ______________7.3
Oxidation Stability (min.) 1440+
Distillation:
10% evap ________@131.0°F
50% evap ________@194.0°F
90% evap ________@228.0°F
E.P. _____________@233.3°F
Color: ____________Green
Lead: ____________4.23 g/gal
Torco Mach 110
Specific Gravity____.710
Pump Octain_______110
Distillation _________F
10% evaporation____@160°F
90% evaporation____@211°F
color______________purple
leaded ____________yes
end point___________246
Can anyone comment on theses fuels using the data I was able to get to tell me if one is better than another, and more importantly why? I'm trying to make some sense out of the fuels I use. This looks like it may be a good learning experience for me. Maybe someone else too. :)
Mike, where do you get the Torco fuel locally?
Keith I get the Torco for $4.75 a gallon at my friends gas station/machine shop in N. Scituate. Karls east coast speed sells the C-12 for something like $6.50. I think the Torco and the C-12 are both better than Cam-2, so I buy the Torco. It`s cheaper and my friend sells it.
VP C12 contains no additional oxygen.
Keith - The temp range between the 10% and 90% point on the Torco fuel is fairly narrow with the 10% point being on the high side. Usually fuels like this can exhibit weird quirks and can leave a hole in the fuel curve on engines that run at high speeds with short intake tracts (YZFs CRFs). But the 10% isn't so high that it's guaranteed to exhibit this behaviour. I'd say this fuel is a try it and see call. All bets are off if the fuel is coming from a bulk storage source like a ground tank or large drum. No telling how close to spec the fuel is in those cases.
- Nov 13, 2001
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Watch out I read VP C-12 goes bad,dyno showed the bike lost 1HP after being mixed for only 2 weeks.
C12 will last as long as any other leaded race fuel if stored properly.
- Nov 13, 2001
- 1,178
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According to the guys at ATV News magazine who did the test on VP C-12, 2 week old VP C-12, VP MR-2 the 2 week old C-12 ran 1HP less on the dyno when compared to the fresh C-12. They also have like 3 pages about fuel octane and compression ratios. This is the April 2002 issue.
WELL if it came from them it must be true. :silly:
Excuse me while I go stand in the corner of the internet and bang my head against the wall.
jmics19067
LIFETIME SPONSOR
- Jan 22, 2002
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:)
Rich
you can use this to your advantage. Just imagine how bad pump fuel loses horsepower before you even get into your bike? I find this a very strong and <ahem> credible :confused: reason to make sure the fuel you use is fresh.
Magazines!!!!!
Just because they buy ink by the barrel doesn't mean they know beans about fuel or anything else for that matter. One week, really! Maybe they stored it in an open container.
Two quotes by Samuel Clemmens come to mind.
1) A lie will go halfway around the world before the truth can put on its shoes.
2) Never fight someone who buys ink by the barrell.
C-12 is an excellent fuel for 2-stroke offroad use. The initial point of the evap curve is low enough to give good throttle response and the end point is high enough to provide some cooling effect. As Rich said the evap curve is nice and smooth with no hitches. This contributes to consistent results.
It's better to have 47 horses in the corral than 48 out on the range. ;)
Just because they buy ink by the barrel doesn't mean they know beans about fuel or anything else for that matter. One week, really! Maybe they stored it in an open container.
Two quotes by Samuel Clemmens come to mind.
1) A lie will go halfway around the world before the truth can put on its shoes.
2) Never fight someone who buys ink by the barrell.
C-12 is an excellent fuel for 2-stroke offroad use. The initial point of the evap curve is low enough to give good throttle response and the end point is high enough to provide some cooling effect. As Rich said the evap curve is nice and smooth with no hitches. This contributes to consistent results.
It's better to have 47 horses in the corral than 48 out on the range. ;)
- Jun 15, 2001
- 2,552
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lol, fishhead. Anyone who quotes Twain is a friend of mine and of course, correct. ;) Particularly in this instance. I've been using C12 recently, & have enjoyed, for the first time in a while, a relieving decrease in time spent cursing jetting woes or trying to achieve reasonable throttle response.
In reality, I think pump fuel's just gotten so damn bad lately that the gap in performance and consistency has broadened terribly. And I've had no problems with storing the C12. Also, hp is a mute point, since (at least to me) the biggest reason to use something like C12 is to improve throttle response and to obtain consistency in jetting. I really haven't been able to tell any difference in "peak" horsepower c/t pump gas, since I can't use everything I've got already. I could see how a fuel with a nice curve and oxygenates could help the cause with a screaming 125, but me? Nah. I'm just a spode that can't use a 3rd of what I've already got. :silly:
In reality, I think pump fuel's just gotten so damn bad lately that the gap in performance and consistency has broadened terribly. And I've had no problems with storing the C12. Also, hp is a mute point, since (at least to me) the biggest reason to use something like C12 is to improve throttle response and to obtain consistency in jetting. I really haven't been able to tell any difference in "peak" horsepower c/t pump gas, since I can't use everything I've got already. I could see how a fuel with a nice curve and oxygenates could help the cause with a screaming 125, but me? Nah. I'm just a spode that can't use a 3rd of what I've already got. :silly:
Thanks Rich, but what part of the fuel is doing the evaporating? Is that like the MBTE that evaportates so quickly, that it evaporates before it can drip? Or am I completely lost here?
I guess I was looking for an explaination on what the numbers mean. Is there something available in the form of a link or a book at the library that I could read about the good bad and ugly of fuels? Or, if you would rather provide a dissertation right here; that would work too. :)
As always thanks for any insight that you can provide.
I'll take a stab here.
The evap curve is provided to let the tuner know what the physical properties of the fuel are. A fuel with a fairly high initial evap point might be best used in a 4 stroke with higher inlet tract temps as the evaporation provides cooling to the intake tract, valves and piston crown. This property enhances cylinder filling. This is a good thing. As an extreme example fuels with a very high initial evap points are often used in turbo applications because low evap point fuels are less ideal as evaporation produces expansion which interfers with cylinder filling and robs power. Not a good thing. The end point is important because if the fuel in the combustion chamber does not get to the end point of the evap curve prior to combustion then there is unburned fuel wasted in the combustion process. Again, this is not a good thing. So the temerature characteristics are different for different applications. Matching the temp charateristic of the fuel and engine is a good thing. This is one reason there are so many different flavors of fuel out there. Generaly speaking offroad 2 strokes prefer a fuel with a fairly low initial evap point. A fuel with a too high of an initial evap point kills throttle response. This is what usually occurs with octane boosters.
I know very little about this subject so if anyone can further enlighten me on the subject or correct my misunderstandings please feel free to do so.
Gasoline is a homogenous mixture of different molecules, kinda like Jim Beam, The more volatile or lighter fractions evaporate first and so on. If you heat up your Jim Beam the alcohol will evap first then the water and finally the brown goo from the charred oak barrels that give it color and flavor.
The evap curve is provided to let the tuner know what the physical properties of the fuel are. A fuel with a fairly high initial evap point might be best used in a 4 stroke with higher inlet tract temps as the evaporation provides cooling to the intake tract, valves and piston crown. This property enhances cylinder filling. This is a good thing. As an extreme example fuels with a very high initial evap points are often used in turbo applications because low evap point fuels are less ideal as evaporation produces expansion which interfers with cylinder filling and robs power. Not a good thing. The end point is important because if the fuel in the combustion chamber does not get to the end point of the evap curve prior to combustion then there is unburned fuel wasted in the combustion process. Again, this is not a good thing. So the temerature characteristics are different for different applications. Matching the temp charateristic of the fuel and engine is a good thing. This is one reason there are so many different flavors of fuel out there. Generaly speaking offroad 2 strokes prefer a fuel with a fairly low initial evap point. A fuel with a too high of an initial evap point kills throttle response. This is what usually occurs with octane boosters.
I know very little about this subject so if anyone can further enlighten me on the subject or correct my misunderstandings please feel free to do so.
Gasoline is a homogenous mixture of different molecules, kinda like Jim Beam, The more volatile or lighter fractions evaporate first and so on. If you heat up your Jim Beam the alcohol will evap first then the water and finally the brown goo from the charred oak barrels that give it color and flavor.
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