Our first attempt to compare...
Our first attempt to compare the performance of 91-octane, pump premium gasoline to E-85 was at Southwest International Raceway in Tucson, Arizona. The Charger weighed in at a hefty 4,256 pounds, but ran 11.60s at 118 mph with a 5,250-foot density altitude. We were impressed with the power, but it was consistent results we were after, and three problems emerged. The Charger is a street car with no line-lock for consistent tire heating; it has a production shifter that occasionally goes from first to third, not first to second to third; and we were running entirely too close to the NHRA limit of 11.50 seconds without a rollbar. We were at risk of being barred from the track if we happened to make a really good run. So it was off to the dyno.
We believe the current world situation will force the U.S. to fully develop our own energy supply in the not-too-distant future, and that E-85 will play a huge part in that transformation. So until hydrogen, or whatever it is that comes along to answer everyone's dreams, let's further look at E-85's possible benefits for the high-performance enthusiast.
We're sure everyone already knows what E-85 is, or at least has heard of E-85, and what it's made from, but just in case, we will begin with a short quiz. Is E-85:
A: 85-percent moonshine liquor poisoned with 15-percent gasoline so we won't drink it?
B: A lower-cost race and high-performance street fuel?
C: An alternative new car, SUV, and pickup truck pump premium? (flex fuel)
D: A small first step for the United States towards independence from foreign oil?
E: All of the above?
There are no wrong answers to this quiz, but (E) is the most correct.
The United States is taking a small first step towards independence from foreign oil. E-85 is 85-percent plant-based ethanol and 15-percent unleaded gasoline. It appears that E-85 will be readily available and relatively inexpensive across the entire U.S. within the next couple of years. In southeastern Arizona, E-85 is 30 cents a gallon less than 87-octane regular, and about one-third the cost of 100-octane race fuel. True, we will use about 25- to 30-percent more E-85 than gasoline per application, but do the math and it still comes out to be a great value for a 105-octane fuel. That's right, E-85 carries a 105-octane rating.
Performance Carburetor supplied...
Performance Carburetor supplied two of their Stage II 4150 HP based blow-through carburetors for our tests. The one on the left was calibrated for pump premium and 15-psi maximum boost. It was also set up for dash 6 fuel lines from the boost-referenced fuel pressure regulator. The carburetor on the right was calibrated for E-85 and 15-psi maximum boost, but was set up for dash 8 fuel lines from the boost referenced fuel pressure regulator, as needed to supply the 20- to 30-percent more volume E-85 required. The F-1 ProCharger with a 70-tooth crank pulley and a 44-tooth supercharger pulley reached 15.5 psi during the tests, and the carburetors worked well.
What did we learn? Figure...
What did we learn? Figure 1 shows comparisons of rear wheel torque and rear wheel horsepower with E-85 and 91-octane pump premium. The comparison's "curves" were nearly identical for each set of runs, but the E-85 clearly outperformed the 91-octane traditional fuel.
During our dyno testing, we...
During our dyno testing, we made jet changes to both the traditional gas carburetor and the E-85 carburetor. Subsequently, we found out that we didn't need to.
On a comparative cost basis, E-85 sounds favorable, so let's look into it a little further. A downside to E-85 is that you need about 20- to 30-percent more fuel running through your carburetor for the vehicle to run properly. If you just try and run E-85 in a vehicle and not compensate with larger jets and whatnot, the vehicle will run lean. Another problem that may arise if you are running old fuel lines is alcohol fuels are more corrosive on some rubbers, plastics, and even some metal parts. We have also heard rumors that the uncombusted ethanol (especially during rich, cold-start conditions) may migrate past the piston rings, resulting in cylinder-wall washing, which reduces cylinder-wall lubrication and could run down into the crankcase, diluting the engine oil. While such occurrences are unsubstantiated and unlikely, there are some special engine oils that add an additional degree of protection until more field experience can be accumulated. If you are, or plan to, run E-85, you may want to look into an engine oil designed to handle such issues. After a quick search, we found an oil called Lubrilon. It's a specialty automotive oil that was specifically formulated for use with all ethanol-blended fuels. Lubrilon multi-viscosity motor oils are SAE and API licensed for use in all gasoline engines, and are engineered to help combat the acids formed when burning any modern ethanol fuel blend, including gasoline and E-85.
On the good side, as we said earlier, E-85 is rated at 105-octane. This is definitely a benefit, but E-85 also burns cooler than traditional gasoline. While that is great for your engine, it also means it may not burn completely if your ignition isn't set up for it, which means you aren't getting all the energy available and are just wasting fuel. So your ignition, including your spark plugs, better be up to the task. If you are planning to run E-85, your engine will benefit remarkably by changing to a colder range spark plug. The reason is that E-85 is prone to cause pre-ignition. If you are converting to an E-85 fuel, we recommend dropping your heat range at least two numbers cooler than your stock setting.