What Xonic said is a bit of a generalization... with strict enough control over timing with sensitive enough knock sensors the Xb and Xa which are both over 10.x:1 comp ratios can run on regular 87 oct... its all in the tuning(ignition timing)

Epitrochoid- Amen!

Peace(sorry about all the posts...)

 

i use 89 octane and was contemplating jumping up to 93...... even though im going up, all the higher octane does is raise the combusion, and burn the fuel faster........ the increased and heathier combusion is good for the engine and does increase torque and hp and ____

 

This is the BIGGEST myth about octane. Seem like every car forum goes though this exercise. So, here we go..

Think of octane as 'resistance to detonation', if the fuel spontaneously explodes on compression, that is detonation, all the fuel just explodes at once instead of burning. Once you achieve enough 'resistance' for the compression you are using, any more is irrelevant.

A better fuel has more energy. Here's a write up about Xylene which is a very good fuel. I used xylene blended with Ultra 94 in my RX8.

About xylene from Doctorr at the rx8club.com...


Xylene is the perfect gasoline.

When oil companies blend their gas, they have to mix the cheap stuf, usually 'straight run' components, with the good (high octane/expensive) stuff. It is a fine balancing act, they run as much of the cheap stuff as they can to meet the octane spec.
Xylene (and its buddy Toluene) are magnificent gasolines. Toluene is about 114 octane, and xylenes can be anywhere from 115 to 121, depending on the makeup of the different isomers.

Both are very high energy fuels.

(Don't confuse octane with energy potential, we mix in a lot of Butane/Propane into the gasoline because it is cheap and has a nice 94 octane, but it is an awful fuel, not dense, no oomph, results in a poor 'drivability' index, another spec we have to meet.)

You can read in various Formula 1 articles of a time when teams ran 80% toluene mixes, until that was banned.

Xylenes have lots of uses outside gasoline, as you know we can sell it for lots o'cash as paint thinner/solvent, and toluene is also worth plenty - we make it into Styrene plastic and ship it to Japan and the USA. We don't like to have to put it into the gasoline. But gas pays the bills, so if a blend comes up short on octane, in goes just enough 'X&T' to get them out of the jam.

I can assure you that one or two gallons of xylene (or toluene) to nine of good quality pump gas will do wonderful things for your power, from an octane and from an overall power point of view. Trust me, you will not get anything like it from an oil company - most 'race gas' still has Lead additives to boost the octane, not X&T.

It is also relatively simple to work out your final octane in your tank - just add the octane of the pump gas and the octane of the X/T. So 8 gals of 94 octane and 1 of 114 octane = 866, divide by 9 = 96.2 ( if there is no Lead involved, it screws up the result)
It is best to keep it less than 40% of the total, because you are also diluting the other additives, the detergents/anti-static/stability package.

And never believe the crap on the "Octane Booster" bottle - 'adds 2 to 4 octane points' - they mean points as in "point one of an octane" 12 ounces to ten gallons may make 0.1 difference (very expensively!)

 

How many ways can the facts be stated??? People see "OCTANE" and must not even read anything that's been posted just spew silly myths over and over

 

hmm well i know if u go to the scion website it it say something about gas under the FAQ but i have a 02 chevy cav right now and i use shell vpower it 194 a gallon but i live in md....

 

Yes you are right!!!
havent you read anything above this, not just from me but everyone else who can back up their facts instead of your media/urban myth driven placebo buttdyno?

Raise the combustion??? Whats that? Sounds scientific...
Burn the fuel faster??? Nope it actually burns slower(flame front and propagation)
Healthier combustion... and ____ is right...

Peace

 

That quote is soooo wrong!

If the can says that it gives you 3 octane points, it means it will bump it from 93 octane up to 93.3 octane. Making the boosters much more expensive.

Find some toulene and mix correctly if you want some cheap race gas.

There is ZERO benefit to running over 87 octane if the car was designed right. Might as well use spring water to wash your car and dry clean your mats.

-dp