Anyone run toluene/xylene in their EVO?
Anyone run toluene/xylene in their EVO?
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From: SoCal
Yes. It is also frequently used as the main ingredient in octane booster and is readily available at paint stores, chemical supply stores, etc. Has an R+M/2 octane of 114. Xylene is 117.
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From: SoCal
Don't run straight toluene-- mix it with premium to raise octane. I probably wouldn't exceed about a 6:1 gas to toluene ratio since gas has other things in it (lubricants, cleansers, etc.) necessary for your engine.
For example, for an 21 gal. tank you might use (in California):
18 gallons of 91 octane
3 gallons of toluene
This gives a final octane of:
((18*91)+(3*114))/21 = 94.3 Octane
Heff
For example, for an 21 gal. tank you might use (in California):
18 gallons of 91 octane
3 gallons of toluene
This gives a final octane of:
((18*91)+(3*114))/21 = 94.3 Octane
Heff
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From: SoCal
Yeah. 6:1 ===> ~15% or so. This keeps the toluene level within some ASTM specs for gasoline. The problem, I think, with putting more is that toluene is such an effective anti knock fuel it also means that it is more difficult to ignite at low temperatures. This may cause problems during startup/idle.
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Originally posted by Claudius
I heard from various sources that the toluene effect stops at about 15% of the total mixture, ie you shouldt put over 15% toluene, or that it may harm or so. Anybody know more about this?
I heard from various sources that the toluene effect stops at about 15% of the total mixture, ie you shouldt put over 15% toluene, or that it may harm or so. Anybody know more about this?
Gas companies generally don't place more than 30-35% in the mix, so adding an additional 15% should be safe, but adding more could be a bit of a gambling game.
NOTE: I'm not speaking from authority here but purely reciting information from various web sites and forum threads I have encountered on the subject.
I put in a solid day of research on the subject. If you'd like to look at my sources of info send me a messaage...
First let's get the additives out of the way. For Octane boost some add as little as 3 points and some off-road formulas will add over 10. Points are ONLY a tenth of an octane rating, meaning that if you added a typical octane booster like the street grade of 104+, you're only getting a 0.7 boost in octane. Kinda lame if you ask me. Also, you've got to be careful because some of these use MMT to boost octane, which is bad for your emissions control stuff like O2 sensor and catalytic converter... so prolonged use may even give you a check engine light, since it seems that Evo's ECU is pretty sensitive.
I'm assuming that someone would add Toluene or Xylene to gas in order to boost your octane rating. It's unconfirmed but Toluene has an octane rating of 108 and Xylene has an octane rating of 117. I did some quick math and figured out that at $10.00 per gallon for Xylene, it would only raise 13 gallons of gas a little over ONE octane rating, making the tank cost somewhere around $2.50 per gallon. I figured a 94 octane gas and xylene mix to get to 100 octane would cost somewhere around $3.25 per gallon. Alternatively, I found that some Select sunoco stations sell thier GT100 gas. I haven't been to one yet but it's worth checking out to see what it costs without having to worry about if xylene has any adverse affects to other engine systems.
An important fact I found along the way is that having too much octane just costs you more money. In very loose terms octane is a rating that shows how well the gas can burn efficiently (not detonate) under heat, changes in pressure, and other very minute foriegn combustion that goes on. The good news is that too much octane doesn't harm your engine, since the fuel burns efficiently anyhow.
Another important fact I found out is that it's more important that fuel's sensitivity is low. To determine the octane rating two tests are done to produce a research octane number (RON) and a motor octane number (MON). The RON is always higher because of the test that is done, in severely rough terms the RON is determined using an engine running at 900rpm, the MON is determined using 600rpm. The difference between the two is the fuel's sensitivity. Typically (almost relyably) pump gas has a sensitivity of 10, meaning that 93 octane gas has a MON of 88 and a RON of 98 (look in your evo manual, notice something familiar?) A low sensitivity means that the fuel will retain more of it's burning efficiency at higher rpms, or higher heat and compression.
My research on this subject has slowed but is continuing. Hope this helps.
First let's get the additives out of the way. For Octane boost some add as little as 3 points and some off-road formulas will add over 10. Points are ONLY a tenth of an octane rating, meaning that if you added a typical octane booster like the street grade of 104+, you're only getting a 0.7 boost in octane. Kinda lame if you ask me. Also, you've got to be careful because some of these use MMT to boost octane, which is bad for your emissions control stuff like O2 sensor and catalytic converter... so prolonged use may even give you a check engine light, since it seems that Evo's ECU is pretty sensitive.
I'm assuming that someone would add Toluene or Xylene to gas in order to boost your octane rating. It's unconfirmed but Toluene has an octane rating of 108 and Xylene has an octane rating of 117. I did some quick math and figured out that at $10.00 per gallon for Xylene, it would only raise 13 gallons of gas a little over ONE octane rating, making the tank cost somewhere around $2.50 per gallon. I figured a 94 octane gas and xylene mix to get to 100 octane would cost somewhere around $3.25 per gallon. Alternatively, I found that some Select sunoco stations sell thier GT100 gas. I haven't been to one yet but it's worth checking out to see what it costs without having to worry about if xylene has any adverse affects to other engine systems.
An important fact I found along the way is that having too much octane just costs you more money. In very loose terms octane is a rating that shows how well the gas can burn efficiently (not detonate) under heat, changes in pressure, and other very minute foriegn combustion that goes on. The good news is that too much octane doesn't harm your engine, since the fuel burns efficiently anyhow.
Another important fact I found out is that it's more important that fuel's sensitivity is low. To determine the octane rating two tests are done to produce a research octane number (RON) and a motor octane number (MON). The RON is always higher because of the test that is done, in severely rough terms the RON is determined using an engine running at 900rpm, the MON is determined using 600rpm. The difference between the two is the fuel's sensitivity. Typically (almost relyably) pump gas has a sensitivity of 10, meaning that 93 octane gas has a MON of 88 and a RON of 98 (look in your evo manual, notice something familiar?) A low sensitivity means that the fuel will retain more of it's burning efficiency at higher rpms, or higher heat and compression.
My research on this subject has slowed but is continuing. Hope this helps.
Last edited by netmand; Apr 6, 2003 at 07:28 AM.
Thread Starter
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From: SoCal
Toluene = 114 octane, not 108 as you said. Also, the 76 stations selling race gas (100 octane unleaded) around here are $5.49 per gallon!!! (in SoCal) Ridiculous. Anyway, I just bought a gallon of toluene for $6.00...
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From: SF
Toluene works awesome... I usually use about 2gallons/tank in my s/c'ed m3. I dont think I would use it every tank, but its a fun treat every now and then especially for those of us stuck with crap 91 octane.