Discussion
avance70 said:
what are the advantages of the gasohol?
The ethanol in it is a carbon-neutral renewable resource. Also, it burns somewhat more cleanly than straight petrol.
avance70 said:
can i use gasohol in my reault clio 1.2 petrol, or is gasohol only for diesel engines?
Gasohol is for petrol engines, the stuff for diesels is called biodiesel. I dare say you could put it in your Clio, but why bother, and where would you get it?
avance70 said:
can i produce my own gasohol by just adding 10% ethanol after tanking at the gas station?
Gasohol is more like 85% ethanol IIRC. There are other things that are cheaper, more readily available and more worthwhile as a fuel additive than ethanol, but unless the Clio has a knock-sensing advance control ignition system (which I don't think it does, though I am prepared to be corrected) you won't see any difference.
Pigeon said:
There are other things that are cheaper, more readily available and more worthwhile as a fuel additive than ethanol
i do keep it in good shape, but i think the age and the mileage are doing their part.
my clio has done 90000 miles (10 years old) and its a very small city car... which additives should i consieder? (fuel and other)
Um,
If its its gasohol and its 85% ethanol then you're clio won't run on it unless you get it remapped.
the reason is because the difference in calorific value of petrol and ethanol. You'd need to inject more gasohol to keep the engine from running lean.
Also there would be no benefit (power or economy) unless you could rebuild the engine with a higher compression ratio (or advance the ignition timing).
Hope this helps.
Andy
If its its gasohol and its 85% ethanol then you're clio won't run on it unless you get it remapped.
the reason is because the difference in calorific value of petrol and ethanol. You'd need to inject more gasohol to keep the engine from running lean.
Also there would be no benefit (power or economy) unless you could rebuild the engine with a higher compression ratio (or advance the ignition timing).
Hope this helps.
Andy
I thought he was planning on making his own gasohol by putting 10% or so ethanol in petrol, not buying 85% stuff in Brazil and shipping it over 
My comment about other more worthwhile and cheaper additives was not referring to things like STP in little bottles, but things like cellulose thinners, which would give a significant octane boost if you put 10% in petrol. However, as has been pointed out many times, that on its own won't make the car go better. You'd need a knock-sensing ignition system that could advance the ignition to take advantage of it. Raising the compression would be of greater advantage but tends to leave you stuck if you run out of thinners
The difference in fuelling rate required when using ethanol is not due to the different calorific value, but the different stoichiometry of the oxidation of ethanol compared to petrol. Basically you need a much richer mixture to use up all the oxygen. Since pretty well everything these days adjusts fuelling using feedback from an exhaust oxygen sensor, the ECU should apply appropriate enrichment automatically as long as you don't use too high a proportion of ethanol - I'd guess 10% would be fine, but 85% would take you well outside the possible range of adjustment unless you fitted bigger injectors etc.
My comment about other more worthwhile and cheaper additives was not referring to things like STP in little bottles, but things like cellulose thinners, which would give a significant octane boost if you put 10% in petrol. However, as has been pointed out many times, that on its own won't make the car go better. You'd need a knock-sensing ignition system that could advance the ignition to take advantage of it. Raising the compression would be of greater advantage but tends to leave you stuck if you run out of thinners
The difference in fuelling rate required when using ethanol is not due to the different calorific value, but the different stoichiometry of the oxidation of ethanol compared to petrol. Basically you need a much richer mixture to use up all the oxygen. Since pretty well everything these days adjusts fuelling using feedback from an exhaust oxygen sensor, the ECU should apply appropriate enrichment automatically as long as you don't use too high a proportion of ethanol - I'd guess 10% would be fine, but 85% would take you well outside the possible range of adjustment unless you fitted bigger injectors etc.
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