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octane booster


Guest leoibb
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i was told bout these octane bosters with the lead aditive and wondered usin it is there any benefit? i am assuming these engines we used was designed to run on leaded fuel , and lead being a lubricant would there be any reason not to use it>

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Leoib,

The lead in petrol is an anti-knocking additive, not a lubricant. Two stroke engines use the 2 stroke oil mixed into the petrol as their lubricant. Although the Solo 210 was designed initially for leaded fuel, it can run quite happily on either- as long as you have the correct mix of 2 stroke oil in the fuel. I belive Adventure state in their manual that unleaded is recommended.

Octane boosters will provide marginal difference on a 2 stroke- the 2 stroke system has such great inneficiencies that it will make little difference. Did you know that at full throttle, almost 1/4 of the fuel passes out of the exhaust unburnt? Direct injection 2 strokes are the future.... efficiency of a 4 stroke, and power to weight ratio of a 2 stroke.

GD

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Probably seemed like a great idea at the time-

Thomas Midgley, Jr. (May 18, 1889 – November 2, 1944), was an American mechanical engineer turned chemist. He developed both the tetra-ethyl lead (TEL) additive to gasoline and chlorofluorocarbons (CFCs), and held over a hundred patents. While lauded at the time for his discoveries, today his legacy is seen as far more mixed considering the serious negative environmental impacts of these innovations. One historian remarked that Midgley "had more impact on the atmosphere than any other single organism in Earths history." [1]

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Apparently some paramotoring manufacturers and engine companies have already looked at it, but the cost is inhibiitive at present. It needs a computer module to govern the injection system- but even the injection and metering system is quite complicated too.

Advantages would be-

-Greater fuel economy on a 2 stroke

-More efficient use of fuel and cleaner emmissions

-Lighter and more powerful than a 4 stroke

-Can be used in any orientation

-No carb, no needles- auto adjustment

Disadvantages-

-Cost

-Need to carry electrical power supply for the control system

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It really shouldn't be that much of an issue to produce this, although there will be weight added in the form of the CPU, various sensors and a high pressure fuel pump to deliver to the injector. Many motors have an electric system, so that part becomes almost trivial. To make the most of the advantages of an injection system, it would be best to have an oxygen sensor in the exhaust in order to provide feedback for a closed loop. However, such devices are rather prone to the sort of contamination that might be likely in a two stroke exhaust. On the other hand, you could have a simple metering system, where the carb. butterfly actuates a potentiometer which together with air and engine temperature sensors, and an ambient atmospheric pressure sensor provide the inputs required for the injection system to map a suitable injector period to meter the required amount of fuel. I would probably still stick with premix rather than a pumped oil supply, as it removes a little extra weight and complexity.

I can imagine all the components adding perhaps a couple of pounds (a kg) of weight to the motor, but given that you could probably reduce your fuel load by 25% for a similar duration, this seems reasonable.

On an experimental level, there are motorbikes with manifolds and injectors that could probably do the job (an 800cc four cylinder machine should provide a reasonable starting point). If you chose one that is compatible with a 'Power Commander' device, it becomes a doddle to remap the fuel injection, either manually or on a dynamometer. You would just have to convince it to deliver fuel once per revolution instead of the four strokes two revolutions.

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I would probably still stick with premix rather than a pumped oil supply, as it removes a little extra weight and complexity

If you do not have a pumped oil system then the 2/ mixture would have to be injected in the the crank housing and follow through the engine as it does now so you would still have fuel going straight through.

The savings with injection come from the fact that only oil and air are wasted as the fuel is only injected at the firing point so you do not have any waste fuel going down the exaust.

Pete b

At least that's how I understand it

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Yes Pete- you're right.. It's precision metering- that's the key. Infact if it's done right, you don't need the backpressure/shockwave from the tuned pipe to force unburnt fuel back into the head either- this would make the exhaust system much smaller and lighter..

Here is an illustration of a conventional 2 stroke system -

engine10.gif

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I was going to suggest the old moth ball additive, but thought I'd look for some factual(ish) data on it as I heard it as a rumor too.

Turns out, not such a good idea, even when they were nathalene based.

http://stason.org/TULARC/vehicles/gasol ... ctane.html

Adding octane is beneficial to avoid detonation or preignition but does not unleash or add power to the fuel, it may have gained that reputation because it allowed the throttle jockey to use more of the throttle range without damage however:

http://stason.org/TULARC/vehicles/gasol ... power.html

The old seat of the pants dyno giving false readings again.

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