Slo_crx1

That's because gasoline made from a toluene base. It's mixed with other additives like "cleaning agents" and such for pump use. F1 used to run a pretty strict diet of 98% toluene and 2% fillers back in the day, but something changed in the rulebooks a few years back and I don't think they can run it anymore. I haven't kept up with it in a long time, so I don't know the exact story anymore. Pump gas is something like a 60% toluene base iirc.

fe3tcourier

----, i could have sworn it was only 85%

whats the rest? diesel? it would nearly have to be to come out so low in octane if this was the case. i strongly doubt this.

not so many aromatics are used in fuel now, more than with leaded, but not so much. i'm sure waffles will chime in here with a break down. i cant be arsed looking it up.

b18.

They took out the toluene the same time they took off the turbochargers, some finicky old ****** who was head of a commission or something figured it was too dangerous, or unfair. Just like the class B rally cars back in the day, something about a 1000hp 1.3L Peugeot didn't sit right with someone in charge of the rules.

Toluene is formed by the reformation of gasoline after it's undergone hydrogenation, you can't specifically change the octane by diluting petroleum with heavier carbon chains, you get weird separation and formation of tar compounds or paraffin chains, and effectively the aqueous product is going to have a lower "octane" rating than it did before you diluted it. This is one of the reasons they have to change the entire fuel system should some moron put diesel in a gasoline tank, gunky gunk.

This explains it rather welll:
http://members.aol.com/profchm/Petroref.html

Arsed. :1

TurboG

I when i was using toluene i was told to throw a couple capfulls of ATF in it because toluene dries out the fuel system because of its pure JDM goodness.

apparently

fe3tcourier

i've mixed diesel and gas together and not had any separation. maybe i just didnt notice.

i was told to put atf in with mine too, but ignored that advice. no part of my fuel system really needs lubrication. the pumps are ok running on alcohol, and the injectors i can replace if/when they fail from it. i strongly doubt that the 2/3 of lubricants/additives left in there with a 33% mix are insufficient to do what they need to do.

b18.

Oh it works, just not chemically perfect. Like if you drew up the supposed reaction for what's supposedly happening.

You'd have a close model, but different chains would come out that you'd expect, (emissions restrictions will hate you).

fe3tcourier

so, then is he right, is typical gas 60% toluene?

if it was 50% toluene and 50% (something that has octane of zero) overall octane would be in the 60 region.

75% and it would be in the 90's where it is, BUT, its not mixed with stuff with an octane rating of zero, so i reckon there is stuff all aromatic content because if there was a lot, the octane would almost have to be higher.

your take on the composition?

b18.

On average there is 0% toluene in pump gas.

Gasoline is obtained from fractal distillation of crude oil, (boiling off different compounds at different pressures, google vacuum distillation). Toluene is obtained from reformation of gasoline through electrophilic aromatic substitution.

The average substitute in gasoline is benzene, which is a much cheaper and easier to obtain aromatic hydrocarbon (boils off at a lower temp), the methyl group tacked onto benzene (methylbenzene = Toluene) makes it around 25 times more reactive than your run of the mill benzene molecule.

Sad but true.

fe3tcourier

dunno about the states, but benzene is regulated to 0.5% or something in nz gas. all the aromatics are because they = cancer.

i agree about toluene not being in gas.

putting it in gas though, now that is a good idea if you can be bothered :-)

b18.

Yea, clean air acts like to pretend like all hydrocarbons aren't carcinogens

Average percentage was something like 20% in 2004, I think they replaced it with some aliphatic compound garbage, cyclopentane?

Like it's any better, electrolysis of hydrogen through the alternator would be a good additive to raise the octane, besides straight water.