[Macleod]

Does anyone have any recommendations on a octane booster? I filled my car up with regular by accident yesterday. It was only like half a tank, but I have had the Supra for almost three years and have never put anything less than supreme. Any feedback would be greatly appreciated.

 

[Boost Junkie]

I would not trust any of those so-called octane boosters. If you have a half tank of 87 and a half tank of 93, you presently have 90 octane in the tank, so you're little worse off than California people always are with their 91 octane premium. Either just drive that tank of fuel out without getting into more than about 14 PSI boost, or drain it out (you can use a 5/8" hose and siphon it out if you don't have any other mechanism). Or, you could burn it down to where it'll hold about 7 gallons and fill up with 100 octane (if you have access to this locally) and bring the octane back to at least as much as your normal 93.

 

[hiken]

Do not put Octane Boost in your car! Just fill up with high octane and empty the tank on low boost...

 

[Nick 95 6sp]

If you can find some locally, you can add a couple gallons of xylene or toluene to your half tank of low octane and bring the octane up safely. I just cut & pasted this from a site discussing octane:

"...by using aromatic toluene and xylene as octane-boosters, you get none of the bad side-effects of using organo-metallics (cancer and engine-deposits) or ethers & alcohols (low gas-mileage and rotting fuel-lines). By using just two gallons of xylene in a 15-gal tank of 91-octane pump gas, you've brought the octane-rating up to 94.5..."

 

[Supra-Holic]

Do not put Octane Boost in your car! Just fill up with high octane and empty the tank on low boost...

+1

Then fill up and reset your ECU a couple of miles later.

 

[8valveprick]

Do not put Octane Boost in your car! Just fill up with high octane and empty the tank on low boost...

I agree. Just drive it till you need more gas and don't beat on it. The high octane is for knock resistance mainly. If you keep the boost down it shouldn't matter.

 

[Beau]

Do you need a mixture of Xylene and TOulene, I thought one was kinda like equiv of 100 octane, and the other is like 95? True?

Its hard for me to find high octane gas around here.

 

[Nick 95 6sp]

^ you don't really have to mix the two. These forumulas are well published all over the internet, not my personal concoction:

FORMULA 1
Toulene
R+M/2...114
Cost...$2.50/gal
Mixtures with 92 Octane Premium
10%...94.2 Octane
20%...96.4 Octane
30%...98.6 Octane
Notes: Common ingredient in Octane Boosters in a can. 12-16 ounces will only raise octane 2-3 *points*, I.e. from 92 to 92.3. Often costs $3-5 for 12-16 ounces, when it can be purchased for less than $3/gal at chemical supply houses or paint stores.

FORMULA 2
Xylene
R+M/2...117
Cost...$2.75/gal
Mixtures with 92 Octane Premium
10%...94.5 Octane
20%...97.0 Octane
30%...99.5 Octane
Notes: Similar to Toulene. 12-16 ounces will only raise octane 2-3 *points*, I.e. from 92 to 92.3. Usually mixed with Toulene and advertised as *race formula*.

 

[Beau]

Can you go over 30%? I mean Gas is like $3.50 a gallon for 93. SO.. :} Why not buy and run a much higher content? Also does it mess with A/F ratios very much?

 

[Hefti2]

IIRC the prices for Toluene / Xylene have also climbed up.-Unfortunately

 

[John H]

you presently have 90 octane in the tank, so you're little worse off than California people always are with their 91 octane premium.

Not just Cali. I live in Texas and have to drive 3 hours to get anything above 91 octane. I've been trying to source E85 and straight ethanol to mix with my 91, but I've been unsucessful.


JH