| We tested a common additive, Torco, to see if it | | | | desired burn rate in a Kart at 16,000 RPM is very |
| could add performance to your vehicle or increase | | | | different than the target burn rate of something like |
| mileage. Before discussing this product, lets first | | | | a big-block V8 at 9,000 RPM. Too fast of a burn and |
| address key differences between a racing fuel and | | | | you may experience less than optimum power. Too |
| pump fuel. The one everyone thinks of is octane. | | | | slow and your valves may be opening before |
| Under the US octane rating system AKI (Anti-Knock | | | | maximum pressure is reached. |
| Index) pump fuel is graded as (RON+MON)/2. | | | | Without going into further detail such as specific |
| Meaning if a fuel had a RON (Research Octane | | | | gravity, dielectric constant, and numerous other |
| Number) of 96, and a MON ( Motor Octane Number) | | | | variables, you should now have a basic understanding |
| of 90 its AKI would be 93. Race fuels can be graded | | | | that there is a lot more to fuel than just octane. |
| on any of the standards AKI, MON, RON. So what is | | | | Altering these variables randomly can serve to be |
| octane and why is it important for performance? | | | | counter productive. For the purpose of objectivity |
| Octane is what gives gasoline its ability to resist | | | | lets look at one of the most common indicators. |
| pre-ignition. As displacement, compression, boost, | | | | Octane. |
| RPM, go up it becomes harder to keep the fuel | | | | Torco advertises that it can raise 93 pump to 107 |
| mixture from igniting prematurely. | | | | when used in the highest concentrations. Tested in |
| If under load or high heat, you experience knock | | | | the highest recommended mixture we saw an AKI |
| with 87 octane, stepping up to 91 octane is logical | | | | of ~99 though a secondary testing method. 8 full |
| step for both performance and longevity. If you | | | | points from 107 if you assume Torco was implying |
| experience no knock or timing pull at 91 there is no | | | | 107 AKI and not 107 RON. This would mean it was |
| benefit to you stepping up to 93 or higher. Raising | | | | raising 97RON to 107 RON. If you standardize the |
| the octane further would only serve to decrease | | | | results on AKI you will see that 107RON is actually |
| mileage. The additives that raise octane have less | | | | fairly close to 99AKI. This is much better than you |
| energy than the base fuel, effectively lowering the | | | | could hope for with the more common additives such |
| BTUs of the fuel. That is you will make the most | | | | as with xylene or Tulene. If you assume $3.00 per |
| power and have the best fuel economy with the | | | | gallon of 93AKI pump and $17.50 for a can of the |
| lowest octane that is capable of preventing knock | | | | Accelerator that works out to $6.50 a gallon. With |
| under your specific conditions. | | | | race fuel such as VP and Sunoco in the $5.00 |
| Another major distinction between race and pump | | | | neighborhood this does not make since. On the other |
| fuel is RVP (Reid Vapor Pressure). The easiest, | | | | end if the spectrum, you could mix 1 can with 20 |
| overly simplified, way to think of RVP is as a system | | | | gallons. In areas where only 91AKI is available, this |
| to rate the tendency for the fuel to want to | | | | makes a little more sense at ~$3.80 per gallon to end |
| evaporate. The lower the number the less tendency | | | | up with 93AKI. |
| the fuel has to evaporate. In general racing fuels | | | | So an additives replace race fuel? No. Do they have |
| have a much lower RVP than would be found in | | | | limited applications? Absolutely. If you have a |
| pump fuel due to the poor starting characteristics | | | | legitimate need for slightly more octane this is a |
| that come along with low RVP fuels. | | | | great way to go. If you are tuning a highly modified |
| Burn -speed is another major difference. Race fuels | | | | engine for maximum power stick to race fuels. |
| are blended towards a specific application. The | | | | |