While Mercury Marine is a name involved in circle track racing going back to the 1950s, its Quicksilver Products branded Circle Track engine line is relatively new. Crate engines have found a place in today’s dirt track racing universe, and with Quicksilver engines entering the marketplace, we wanted to know more. Quicksilver helped us out by doing some hardcore fuel testing to determine how the engines perform on a variety of different fuels and the savings one might expect. We found the results pretty fascinating.
A fuel test with a variety of different fuels can tell a race team what kind of performance they can expect, but will also let a team know what the cost per year is for each of the fuels tested. “This is when the results get even more interesting,” said Quicksilver’s Powertrain Director Mike Horak.
About The Oil & Octane Shop
Founded in 2013, the Oil & Octane Shop is a family-owned, full-retail and wholesale distributor of Lucas Oil, Sunoco, and VP products. It boasts a background of more than 20 years in logistics and 8 years of pipeline fuel-hauling and handling. That experience gave the company the opportunity to work with Lucas Oil to supply Lake Lucas, the drag boat lake in Wheatland, Missouri. In doing so, the Oil and Octane Shop formulated a way to blend an additive package to their bulk fuel, creating a premium blended fuel they are branding as the Green Racer label. When demand for its premium blended Green Racer fuel grew, the Oil & Octane Shop was born.
Setting Up Test Parameters
Odd as it may sound, gas coming from the pumps at your local gas station have a range of variation. There are many reasons why this happens. Age plays a role in the potential energy of fuel. “E85 fuel can measure as low as E30 from the pump,” said Horak. “This happens because the high concentration of ethanol spoils quickly, and it is bought very rarely. E85 is usually less than 1 percent of sales at stations where it is available. To counter this, stations add fresh gasoline over time reducing its ethanol content.”
If the station is using a blender pump, the first gallon of fuel pumped is residual from what the person in front of you pumped. “This means that a five gallon sample of E10 fuel could actually be E5, E9, or anything in between, said Mark Piatt, co-owner of Oil and Octane. “Samples of E85 pumped from stations have been shown to be anywhere between E30 to E85.” Armed with this knowledge, it was important to have a local company that could provide controlled samples for the testing. Oil & Octane’s Green Racer label filled the bill.
The engine parameters were constant with Quicksilver’s CT engines using 1 5/8-inch headers, a Holley 650 cfm carburetor, 205-degree F thermostat, a 270-degree F oil cooler, and conducted on a programmable engine dyno with computerized data collection. Each engine was allowed a 4-hour dyno break between each different fuel test. This eliminated any chance of “power float” in a fresh engine, as well as fluctuations due to engine temperature variances.
Horak explained the cycle used to break-in the green Quicksilver circle track engines: “The engines were broken-in for the testing by following a strict four-hour break-in cycle. The first hour was conducted at 2,000 rpm under a 25-percent load. The second-hour was conducted at 3,000 rpm under a 50-percent load. The third hour was conducted at 4,000 rpm under 75-percent load. The fourth and final hour of break-in was conducted at 5,000 rpm under 100-percent load.”
This break-in format roughly represents the equivalent of running 34 races of 30 laps each. This is very similar to what a normal dirt track engine can expect to see in a full season or two of racing. “This is not an issue for a Quicksilver CT engine that is designed for years of race-duty without having to be refreshed,” claimed Horak. “When most people might consider it to be time for a rebuild, a Quicksilver CT engine is just getting started.”
Setting the best combination of total spark advance and jetting to make the most power for a given fuel and engine combination required several dyno runs. “This was usually between four to eight,” confirmed Horak. “The timing was set for peak-power without any incidence of engine knock.” This part of the testing is important because the fuels tested not only have different octanes, but each fuel also has different characteristics, such as heating value and heat of vaporization, that interact with the engine to deliver power.
“Many higher-octane fuels allow for more spark advance to improve power, delivering better thermal efficiency,” Horak explained. “However, that fuel may then have a lower heating value that delivers less energy per gallon. That is how high-octane fuel may or may not translate into power gains for different engines.”
Quicksilver’s 357 CT and 383 CT engines have different compression ratios and piston speeds because of their different crankshaft strokes. That means they react differently to the fuels depending upon on energy-release-rates and flame-speed. “In the end, there is a very complex set of variables between fuels and engines,” he said. “Fuels & engines behave how they want to, and this testing was designed to sort that out.”
With a test fuel, the engines were put through the paces on a dyno using a method which simulated a typical dirt track race. The engine speed was cycled up-and-down between 3000 to 5500 rpm at wide open throttle every 7 seconds for 60 times to simulate a 30-lap race. This duration is equivalent to a 14-second lap time on a 1/2-mile track. Each test ran for 7 minutes to complete the 30-lap simulation.
The data taken during this simulation included the average values for power, torque, exhaust-gas temperature, air/fuel ratio, and total fuel consumed. Unlike typical dyno pulls that show a peak data point, this test’s average data shows how the engine & fuel perform at a variety of RPM to get around the track.
Finally, the data is compared back to local fuel costs in southern Missouri where the engines were tested. “This data provided an evaluation for a relative cost of power by choice of engine and fuel type,” Horak said. “There are wide differences in fuel costs. These results show the dollar value of power gains depending upon the type of fuel.”
Horak summed up the test results by saying: “In the end, the choice of fuel can make a great impact on a racing budget. This information can help racers decide on where to invest money (tires, shocks, springs, fuel) for performance gains. Two things which showed very little change from test to test were air/fuel ratio for best power and exhaust-gas temperatures.”
Issues To Consider With Each Type Of Fuel:
- Sanction requirements – is a standard fuel required to race fairly?
- Environmental – are there local restrictions on lead toxicity from TEL or regional preferences for oxygenated fuel use?
- Maintenance – Some additives MTBE & TEL can cause spark plug deposits to form.
- Availability – Newer fuel technology such as E85 & I-16 may not be readily available in all regions.
- Storage – Most gasoline & isobutanol fuels can store for years, whereas many ethanol fuels spoil rapidly or can be corrosive to engine components.
- Safety – Methanol was specifically not tested because of safety concerns at the dyno facility that may extend to racers: volatility, invisible flame, odor from carcinogenic formaldehyde emissions.
“All of this translates into less hassle, more time for racing, and lower cost to operate a racing engine for years to come,” summated Horak.
What It Means
The Quicksilver sealed crate engines operated well on every type of fuel tested. VP’s leaded racing fuels topped the octane rating (110 & 105 respectively), and set the standard in horsepower. Use caution in regards to state and local laws in regards to leaded fuels, especially those with the oxygenate MTBE (Methyl Tertiary-Butyl Ether). Some states have enacted laws to ban MTBE in certain areas.
Oil & Octane’s blended E85 108-octane-rated fuel scored well in the horsepower test with a 289 average over the test range. This was the highest average horsepower rating out of the eight fuels tested. E85 fuels have their own concerns despite their ability to create high horsepower and torque cheaper than many other fuels. These fuels can corrode some of the fuel system components that were not manufactured to use high ethanol fuels (like systems in older factory stock cars).
E85 fuels have a hygroscopic nature and pull moisture from the air. The fuel can have poor performance if you are racing in an area with high humidity and the fuel has been sitting in the tank. Pre-ignition, lower MPG, and component-lifespan reduction are other issues associated with E85 fuels, but these are not necessarily problems for race cars.
Where the testing really got exciting was in the lower octane Oil & Octane Green Racer blended fuels with lower oxygenate levels. Their E-0 and E-10 blends held their own in the horsepower/torque testing and provided exceptional cost benefits. These fuels were at the top in each performance category with the cost-per-race-season calculation well below the other eight fuels tested – more than a 50-percent reduction in cost to the nearest competitor. The other brand-named fuel’s tested were estimated to cost from $826.88 to $1,518.75 per season. By comparison, the Oil & Octane Green Racer blend E-0 fuel running on the Quicksilver 357 crate engine for a 45-race season cost an estimated $347.21 and performed within 10 horsepower of the top fuels in the test.
Oil & Octane’s E-10 blend (on the same Quicksilver crate engine) performed equally as well as the top fuels tested and still had a miserly $409.50 price tag on the season. These numbers are proportionally similar with Quicksilver’s 383 crate engine. In our estimation, the Quicksilver 383 circle track crate engine on Oil & Octane’s E-10 blended fuel would be hard to beat in the cost-for-performance benefit analysis.