June 7, 2006
If you frequent any of the popular Mustang Web sites, you're probably familiar with the owner of this black '90 LX hatchback. Gunny's 'Stang hit Westech's SuperFlow chassis dyno packing a stock T5, 4.10s, and a Coast High Performance 347 Street Fighter with 10.8:1 compression that includes AFR 205 heads, a Trick Flow intake/75mm throttle-body combo, and Anderson Ford Motorsport's N-91 camshaft. Despite a rather restrictive (for that size AFR) header design and a chip that was made with more of a temporary, "get-it-to-run and-live-under-Gunny's-thrashing intent" rather than air/fuel levels and timing that were the result of extensive dyno tuning, which is recommended, Gunny's ride got with it in our baseline test, turning the drums with 341.30 hp and 325.70 lb-ft of torque.

Just pour this stuff in the fuel tank, and your car will run like it's (turbocharged, supercharged-fill in the blank). We're all certainly familiar with the sometimes outlandish claims of incredible performance gains that are brought on by different brands of higher-octane gasoline and fuel "boosters" of various types. Yes-gasoline's octane rating certainly does play a key role in the horsepower mix. The higher the rating, the better (for making big power) seems to be the popular sentiment shared by most gearheads.

When it comes to the pump gas we use in our Mustangs, the octane rating-usually 87 to 93, with the exception of California where 91 is the maximum-represents the total amount of compression capacity the fuel has before it spontaneously ignites. So, using a naturally aspirated 'Stang motor as an example, its compression ratio is the variable that helps determine the correct octane required for making it run at its best. And as power adders such as nitrous, blowers, and turbos help raise the compression ratio of a 'Stang's engine, higher-octane gas is always a requirement-not an option-for making killer power.

Octane is definitely something the folks at Klotz Special Formula Products are familiar with, as the company makes 100- to 118-octane fuels, and even 100 percent, pure nitromethane (the stuff that powers NHRA Top-Fuel dragsters). While these fuel products are geared more toward hardcore racers and heavily modified Mustangs-not the daily drivers of the world-Klotz does make a pour-in-and-go fuel additive for street enthusiasts. The product is called Coxoc, pronounced "Co-Zoc," (PN KL-614; $71.00/gallon), and it goes against the grain when compared with other fuels and fuel enhancers in the Klotz lineup. According to company president, John Klotz, Coxoc basically increases combustion efficiency and promotes cleaner-burning exhaust by adding 37 percent more air (pure oxygen) into the fuel mixture.

More air helps make horsepower. That's another popular sentiment, but it's also one we endorse because we've proven it many times in induction and airflow tests. While the whole air-in-a-can thing seemed feasible to us when the concept was presented, what really intrigued us is Klotz's claim that the oxygen in Coxoc can be a benefit to modified 'Stangs that are on the edge with regard to passing state emissions tests. By sampling the number of hydrocarbons (measured in parts per million) and the carbon monoxide (measured in percent) of the car's exhaust, a state determines whether or not a vehicle is operating in compliance with SMOG laws.

With the help of U.S. Marines Gunnery Sergeant O. Carl White, (aka "Gunny" on many popular Mustang Web sites) and his 347-powered '90 LX, John Mihovetz and George Klass of Accufab for the dyno hookup, and Steve Abbruzzese and Eugene Walde of Westech Performance Center in Mira Loma, California, we conducted a performance test with Coxoc.