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Discussion Starter · #1 ·
i know xylene has a bit more octane

but what is the actual difference between the 2 and which is a more aggresive liquid as far as strength, harmful effects, hard on your parts rating sort of thing

Im mixing in 1 gallon of xylene into 10 gallons in my gas in my car(turbo focus) but am just wondering if xylene is higher octane, why is anyone even using TOLUENE????
 

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Lets go Nets
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well if you think about it this way... you can only have a mix of 70% pump, 30% xylene, xylene i believe is 117 octane.

toulene i think the max mixture is 66% pump 33% toulene, if you used the same pump and stuff you might get the same numbers overall. as for the difference between the fuels, idk.

you might want to use 1 gallon of xylene for every 2.3333 gallons of pump gas, to get the max out of that xylene!

-Brett
 

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Xylene just requires the use on an added lubricant, otherwise it is perfectly safe. Adding ATF or MMO to both is fine for good measure. The octane of ATF is ~98 and it has lots of lubricant and detergent properties.
 
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Discussion Starter · #4 ·
i use 5oz of MMO in the 1 gallon of xylene

I just keep worrying about how its gonna affect my plastic/rubber fuel components, cause its ALL plastic and rubber, literally, pump, tank, line is rubber into metal, intake manifold is even plastic, lol

BUt 1 gallon xylene in 11 gallons of 91 should be dissolved enough to not cause any damage right???
 

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nazthug said:
i use 5oz of MMO in the 1 gallon of xylene

I just keep worrying about how its gonna affect my plastic/rubber fuel components, cause its ALL plastic and rubber, literally, pump, tank, line is rubber into metal, intake manifold is even plastic, lol

BUt 1 gallon xylene in 11 gallons of 91 should be dissolved enough to not cause any damage right???
They suggest using a lubricant at 3% of your "octane boost mixture" so 7% Xylene to 3% AFT/MMO.
 

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How did they come up with the actual octane level for xylene? I have heard anywhere from 104 to 117. I have a gallon of it sitting in my garage since racing fuel is hard to find around here and am trying to figure out the best mixture for 93 octane fuel and xylene with ATF.
 

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Anyone looking at running toluene or xylene might want to take a look at a thread by someone who did some testing on toluene and monitored timing on the stock ECU.
http://www.supraforums.com/forum/showthread.php?s=&threadid=156914

There is also some info I posted there on the Blending Motor octane of toluene. Short version: the effective blending motor octane is what determines how well a mix with pump gas will suppress detonation. For toluene at least, the blending octane is apparently a *lot* less than the research and motor octane usually quoted. The testing done seems to indicate that a toluene mix is not nearly as effective as the commonly quoted octane numbers would indicate. I don't have any info on the blending motor octane of xylene but I suspect the difference is similar to toluene.

Bottom line: Be careful and don't assume a 30% xylene mix is going to be better or equal to good race gas. It's probably not nearly as effective.

Mike
 
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Discussion Starter · #9 ·
Mike,

I wouldn't draw any definitive conclusions at this point. One interesting observation is my first set of graphs. I was on my second 1/3 toluene 2/3 93 mix when that was done. So, I had been running around for over 200 miles boosting some at 1.6kg/cm2 for that time. That first graph is perhaps the best indication of what the stock ECU learned for a mean value timing map. Doesn't look too bad as it looked like timing would have climbed up to the low 20's by redline. I guess the question is how much timing should be pulled at peak torque? The 11 degrees certainly looks like too much on that last pull.

BLKMGK made a comment in which he said that he knows a tuner that said that even on race gas that some retard would still be apparent.

The plan is to get 5 gallons of GT104 and make the same comparison. Then, I'll use a leaded mix of C16 and pump at the same ratio as the toluene. Then we'll have a very good idea of exactly how it performs in comparisons to other racing fuels. Look for the thread to be bumped shortly, I'm hoping the place I get the race fuel from will be open today or later in the week.

A question I have is ECU reset. After a reset I have always driven it 20-30miles and shut the car down a couple times before taking the data. I'm just wondering how long it takes to learn...or do I even need to reset it when I change fuels?

- Greg Johnston
 

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Exists in unleaded gas, adding more may have no effect; Need more than 10% to be effective; Low RVP

This was part of the listing for xylene and the others. It's kind of contradictory don't you think? If I was going to try this with the gallon of Xylene I have would 1 gallon Xylene and 4 gallons of 93 octane plus 4 onces of either Marvel Mystery oil or ATF be acceptable?
 

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I just finished reading a really good book about the fuel chemistry during the big boost era in the eighties. It's about the McLaren cars that used to make 1100bhp out of a 1.5 litre engine at FIVE BAR boost. I can't remember exactly what they used to run on, but at the end of one season the regulatory body decided that the fuel the teams used the next year would have to under ~100 octane. They ended up using a 95% toluene mixture, because although it was knock resistant enough to let them run well over 3 bar boost (not quite as high as the "rocket fuel" they had been using previously) it behaved quite differently at low rpm and temperatures where the knock measurements were taken that determined the octane rating. I can't remember any more of the science, and I lent the book to a mate ages ago so I can't remember what it was called either! It was by a highly respected techincal author though with lots of other publications to his name so definitely not bullshit. Perhaps someone else on here might know what I'm talkinga bout? Interesting stuff, anyway!
 

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damn 5 bar of boost? they run 3 bar with under 100 octane? wow! so its ok to use a bunch of toulene? 95% mixture?

good article silvino, interesting to read about the advantages and disadvantages of all the fuel addatives.

- Brett
 
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