Hey guys/gals, I was thinking of possibly adding some octane booster to my Z06, and was wondering 1) If I should do it, and 2) What kind if any would you all recommend. I do run Premimum in the car, but I was just wondering if I should put any in from time to time, or if I was planning a trip to the track would it help???? Thanks in advance for any advice!

:seeya

 

Kind of a waste unless:

1) You made internal modification to the engine.
2) Maybe for a dyno run with 1/4 tank.
3) Maybe just on the track.

Now for a factory 11.3/1 compression on a Porsche...... for fun....yea you could tell a slight diff.

 

Thanks alot, that is what I figured, but I thought I would just ask and see what people had to say. Thanks again for the advice.

:cheers:

 

Gasoline is composed of hydrogen and carbon atoms. Octane is gasoline composed of 8 carbon atoms per molecule. The octane rating, traditionally, was a measure of what percentage of gasoline is composed of octane molecules. 90 octane gas is composed of 90% octane gasoline molecules and 10% heptane gasoline molecules and other additives. There are several ways to measure octane which is why you can have gas with an octane rating of over 100.

Octane, amongst the gasoline molecules (heptane, octane, nenane, decane) has the desirable characteristic that it can be compressed quite a lot before it spontaneously combusts. It also burns slower. A 4 cycle car engine doesn't count on spontaneous combustion. Instead it assumes that combustion will occur when the spark plug fires. If the gasoline combusts before the spark plug fires (beginning of power stroke), the engine will not make maximum power and can be damaged

The compression ratio of the engine determines the amount of octane you need in gasoline. The higher the compression ratio, the higher the octane percentage.

Here is the key thing. Your car's performance is a function of how many BTU's of energy it can process in a given period of time. Does higher octane gasoline possess more BTU's per gallon than lower octane gasoline - emphatically NO (octane and heptane have the SAME BTU rating)!! Thus using gasoline with more octane than required to control pre detonation, gives no added value, and may cause unburned gasses to pass directly to the catalytic converter unburned, shortening its life. :)

 

Pre-ignition is not the only concern you have with lower octane fuels. A bigger concern is detonation. This happens when the cylinder pressure and temperture exceed the stability of the fuel and the fuel no longer burns in a controled manner. Instead of 1 constant flame front originating from the spark plug you end up with multiple flame fronts upon combustion that push against each other violantly putting uneven pressure on various parts in the combustion chamber. Under extreme circumstances you end up blowing up the plugs and usualy the piston rings along with the plugs. When detonation occurs you hear it as "pinging." Pre-ignition in its self is not dangerous, but if pre-ignition is happening in a gasoline engine that means you have already exceeded the stability of the fuel, the problem with pre-ignition is that the ECU no longer has control over timing as the spark plug is no longer functioning as your ignition source so pre-ignition almost always leads to detonation. Since the Z06 is not using forced induction or insane compression mild detonation really isn't a big deal but it will hurt performance as the ECU pulls timing out to reduce the knocking. For this reason the engine is equipped with a knock sensor. If your pulling timing your loosing power...now the question is are you loosing timing? WEll I havn't gotten my z06 yet to play with, but I know on my friends LS1 I do hear audiable pinging on a hot day at WOT. But of course here in CA we have the worst premium gas in the country. He could benefit from a few points higher octane. Unfortunately octane is not one of those things where more is always better. You basically want to run with the minimum octane possible and still have a controled burn. The more stable the fuel is the lower the energy content of the fuel. If you were to put VP C16 into a z06 the car would run **** poorly as this 117 octane fuel is formulated specifically for forced induction applications where you are exceeding 250hp/liter and are running 13.0:1 a/f ratio. LS1 and LS6 is tuned pretty rich to prevent detonation on various gas across the country (Since these motors do run fairly high compression for a street car) so if you had a way of leaning out the fuel trim you could definately pickup some healthy horses if you had readily available high octane gas in the area to prevent the engines from knocking with this leaner fuel trim. You guys out there with Sunnoco 94 are damn lucky, I'm sure with some ECU tweaking these cars could pickup at least 10 horsies at the wheel. Octane boosters in general are complete BS tho. When they promise 2-4 octane points that means they raise up 91 octane to 91.2 - 91.4 not 93 to 95. To raise the octane of a full tank of gas you need VOLUME. A common way of raising up pump gas in the forced induction community is to run a significant percentage of Tolulene or Xylene into the tank (along the lines of 20%). Octane boosters are usualy made up of similar chemicals but in such tiny quantities that they don't do much. ITs all marketing gimic, if you look behinde the physics of it you see that one small bottle of any high octane fluid won't be enough to stablize a large quantity of fuel. An exception to this rule is the leaded octane boosters available in Europe and Australia, unfortunately this stuff is illegal to sell here in the states so we can't get ahold of it. Basically forget about running higher octane unless you can get it at the pump or are willing to buy it by the barrell. Hope that helps :).

 

I would add that the major ingreedient for Octane boosters is Tolulene and Xylene in about 50% / 50% mixture (with trifflings of other stuff). Octane boosters cost on the order of $4.00 per pint, with you can get a gallon of Tolulene at a paint store for on the order of $5.00 (a savings of 16X). Both T and X have octane rating in the 114 range, so a little goes a long way.

 

To add to this discussion I will quote a patient of mine from years past. He worked for Texaco(?) (or one of the other major producers/refiners) blending the gas for sale. He suggested (to help me with my slight detonation problems in my old '96 Cobra in Houston) that a pint of toluene per approx 15 gals should get you a point or two. He also said that this was how it was done at the refinery end to quickly, easily (and cheaply) adjust the octane up when needed. It's just nice to know that toluene in the gas tank is OK...

-Ed

 

amen to Toluene! But I have never seen it pass for $5 a gallon. Cheapest I have found is closer to $8 . I think more people will become aware of Toluene as the octane of premium fuels drops to 91 in the rest of the country.





[Modified by 2ndVette, 11:13 AM 9/25/2002]

 

Toluene is good for a poor man's octane boost. The Turbo Buick and Supra guys do it all the time.

Here is the gasoline FAQ, it will explain everything you ever wanted to know about gas.
http://www.gsal.org/articles/fuel/ga.../gasoline.html


They call Toluene doped fuel "rocket fuel"

Here is the FAQ on it.
http://elektro.cmhnet.org/~audi/audi/toluene.html

 

If anyone is interested: you can also add tolulene to fuming nitric acid. the sticky yellow residual (when dry) is TNT--tri-nitrated-tolulene--no wonder its high octane stuff.

Warning, you need to understand chemistry and the handling of dangerous substances to attemp (and survive) this mixture.

 

TNT eh? That might be helpful to know some day :).