DreamWeaver

How high of a octane can I run without dammaging my sensors?

mobius

its not so much the octane level as the lead level. most of the very high octane fuels have lead in them which will coat the sensoprs and ruine them. someone correct me if i am wrong.

J-Rod

The highest unleaded race gas is about 104 octane.

You could of course run on pure Toluene which is 120 octane or so, but you have to heat it to 70^Celcius before you inject in the combustion chamber (this was what F1 did when they ran it).

Higer octane race gas has lead which will eat your 02 sensor in a matter of hours.

DreamWeaver

thinking about mixing some toulene or xylene up to around a 97 octane lvl in tank. So this would be safe?

trackbird

iTrader: (4)

Is there a reason that you need this much octane? With properly tuned aluminum EFI engines you should be able to run 11.0:1 or somewhere close to that with 93 octane. If you are running lots of boost or nitrous or have raised compression a considerable amount, then I could see where the extra octane would be beneficial. 93 octane fuel has the same amount of thermal energy per gallon as 87 octane, it is just more resistant to preignition or detonation....it won't actually make more power in most situations. you will likely need to add additional timing to see any benefit at all (or even break even with your stock power #'s). Also, you are working with some rather nasty chemicals here, I'd not attempt to mix my own fuel products without the proper information for correct mixture ratios for specific octane ratings. Option 2, is to mix 100 octane unleaded race gas with 93 octane to get 97 (much safer). Simply average the octane of each fuel and the amount for your total (leaded gas actually comes out higher than this formula suggests, but it works for unleaded). 10 gallons of 93 octane and 5 gallons of 100....10x93=930, 5x100=500, 930+500=1430, 1430/15(gallons)=95.33333 octane. You can experiment from there. Hope this helps. Good luck.

DreamWeaver

All stations here only sell 91 octane premium. The 100 octane stuff can be found I think at 1 station for about 10 bucks a gl. WAY to steep. I know it used to go for around 4.99 a gl. I know I can mix 20% xylene with 92 octane premium for appx 97 octane - considering i'm only getting 91 octane to begin it will be slightly less. Xylene's octain rating is 117 so at 20% the math is 12x91=1092 , 3x117=351 , 1092+351=1443 , 1443/15=96.2
so mixing 3gl to a 15 gl tank raises octane in this case to 96.2 with no lead??? 3gl of xylene will be much cheaper than 5gl of 100 octane fuel too right?

DreamWeaver

thinking about mixing some toulene or xylene up to around a 97 octane lvl in tank. So this would be safe?

trackbird

iTrader: (4)

That sounds reasonable. My only remaining concern would be any possible negative effect on fuel system parts (rubber lines etc) and to verify that high concentrations of those chemicals won't harm O2 sensors (not the octane rating,but the "large" quantity of your mixers). If you can verify these concerns, I'd say "go for it" (and if you have an old beater...then you have a "test bed". Are there any chemical engineers in the house????

Good luck....let us know what you find out.

parish8

iTrader: (6)

i have done xylene at 30% a couple of times for testing purposes, it is 117octane and about the same price as 100octane race gas per gallon in my area. both are about $4/gallon.

i got the info from http://www.gnttype.org/techarea/misc/octanebooster.html
sounds like they have been doing this for awhile and they actualy mention corosiveness of some of the mixes on that page so that leads me to believe that the xylene is ok. i have put about 10 gallons thru my set up and as far as i can tell have had no bad effects, i have heard of some guys buying a 50gallon drum and running it all the time(at 30%).

i was testing for false knock, runing at 6psi i got the same amount of knock(atap) with 92octane as i did with the 100octane xylene mix. from that i went on to desensitize my knock sensor 22% and my truck went from a 15.1 to a 14flat ET. that is when my tranny died and i haven't got to do anymore testing, i am prety sure i have another 1/2 sec waiting for me to find.

1slowCamaro

A few days ago when I was reading these posts I started to think that my car running like crap might not actaully be from an exhaust leak, but from having lead covered O2 sensors. I was buying 110 octane non oxogenated fuel. It didnt say it contained lead but I guess it didnt say it wasnt either. From what you guys were saying I was very skeptical that this was unleaded fuel. So I ran my gas down and filled up with 100 octane unleaded for $2.95 a gallon and mixed in some 92. Then I changed out my O2 sensors for a nice $185 <img border="0" title="" alt="[Eek!]" src="gr_eek2.gif" /> and now my car runs like 4000 times better! Just wanted to say thanks cause if I didnt read this post I would have never considered that as my problem and I would have put my car away for the winter in bad running condition. That 110 seemed like a sweet deal at $2.90 a gallon. Most stations around here that sell leaded race gas say there is lead in it and the nozzle is to big to fit in the tank. This one fit just fine so I never thought anything of it. Ahhhhh!! Wont be buying that again. <img border="0" title="" alt="[Big Grin]" src="gr_grin.gif" />

Justin