'Cc QuickiesYikes, spikes. During our El Camino road trip, we ran across Brian Pacheco's ice-racing tires for running on frozen lakes. During the summer, he plays around on his personal dirt-track oval in his backyard.
Gimme A Boost
Kris Shields, North Hills, CA: I'm looking for some information on octane boosters. With the price of race gasoline increasing by the day, I'm thinking that an octane booster might be a better way to pump up the octane rating of my regular pump gas. In California, the best gas we can get is 91-octane, while the rest of the country gets 93.
I read some information about a particular octane booster (there must be hundreds of them for sale now). The information I read was that one 12-ounce can of octane booster would pump the gas up by as much as eight points. Does that mean that this one little can would jump 91-octane gasoline up to the equivalent of 99-octane gas? That seems a bit too good to be true. So what's the deal?
Octane boosters do increase the octane rating of pump gas, but only by very small amounts. For substantial increases in octane, mix a little race gas and have fun.
Jeff Smith: We went to the Fram/ Prestone/Autolite Web site and discovered that, yes, Prestone does offer an octane booster called 0 to 60. The company also explains that a "point" of octane boost is equivalent to one-tenth (0.1) of an octane number as listed on the gas pump. So, when a company refers to its octane booster raising the octane level by eight points, that actually means enhancing the pump-gas octane number from 91 to 91.8-big difference. Also keep in mind that octane boosters are not linear in their effect on octane numbers. In other words, adding two cans may increase the octane rating from 91 to 92.6, but after that, there are diminishing returns on how much octane will continue to rise.
The problem with most octane boosters is that for the price of the additive, you get very little return. A gain of two to five points is still moving the octane number an insignificant amount. This will cost anywhere from $5.95 to perhaps as much as $10 or more. A somewhat less expensive approach could be to mix unleaded race gas with pump gas. This is a much more straightforward proposition where mixing 5 gallons of 100-octane unleaded race gas with 5 gallons of premium pump gas rated at 93-octane would generate 10 gallons of gas with an overall octane number of 96.5. This is a gain of 3.5 octane numbers, something no octane booster we've ever seen can achieve. Granted, race gasoline is expensive. Let's say the price of a gallon of 100-octane race gas is $6, raising the octane level of 10 gallons of fuel to 96 octane would cost you $30. Again, this is not cheap.
'Cc Quickies
This is the upstairs room at Scott Gillman's Crested Butte shop he calls the Man Room. It's got a '30s-era headlight-aiming tool and other automobilia along with a killer stereo. Add a big-screen TV and a refrigerator and we'd never leave!
Another possible solution for those of you in the Midwest is E85, which is ethanol or alcohol fuel. E85 generally is rated at 105 octane, more octane than you really need. "Straight" alcohol has an R+M/2 number of 115 and then is mixed with 87-octane pump gas to come up with the 105 pump-gas-octane number. You could mix E85 in equal parts with 87-octane pump gas to lower the total octane count to roughly 96 octane, which would raise the 93-octane premium up to 96 octane. Mixing equal parts 105-octane E85 with 93-octane premium would generate roughly an octane rating of 99.
Keep in mind that mixing E85 with gasoline in equal parts will still mean you have to increase jet sizes. Mixed 50/50 with gasoline, this would still demand a larger overall metering area increase of 15 percent, which is roughly equivalent to five for a Holley carburetor on both the primary and secondary.