The Difference Between Summer and Winter Gas

The Difference Between Summer and Winter Gas & the Need for Fuel Additives.

Summer has its benefits: Fishing season. Dirt-track racing. Wrenching in the garage with the door open and the tunes blaring.

Another benefit is a slight fuel-economy boost. That’s because refiners alter their gasoline and diesel formulations depending on the season, and summer gasoline contains about 1.7 percent more energy than winter-blend gas. Regardless of the time of year, it pays to know a little about what’s going in your tank to ensure you’re properly maintaining your fuel system.

Under Pressure

A primary difference between summer and winter fuels is their Reid Vapor Pressure (RVP). RVP is a measure of how easily the fuel evaporates at increased temperatures. The higher the fuel’s RVP, the more easily it evaporates.

Winter-blend fuel requires increased RVP. If the fuel doesn’t evaporate readily in cold temperatures, the engine will start hard and run rough at cold temperatures.

To achieve this, refiners often blend winter gasoline with butane, a relatively inexpensive additive with a high RVP. They adjust the RVP of the final formulation to as high as 15.0 psi to help the gasoline ignite readily in the cold. 

The Law Restricts Sales

Once the temperature warms up in summer, however, high-RVP gasoline can volatilize more easily, which contributes to increased emissions and air pollution. For that reason, federal law restricts sale of gasoline with an RVP greater than 9.0 from June 1 through Sept. 15. To comply, refiners reduce the amount of butane in the gasoline and instead use pricier additives, hence one reason gas prices generally increase in summer. The blending process also takes longer, adding to the cost. 

Some areas set even lower RVP standards in summer to further limit emissions. California, for example, has a 7.0-psi limit. Given the state’s climate, refiners may sell summer-blend gas as early as April 1 and as late as Oct. 31.

For the most part, the semi-annual switch from winter to summer gas and vice versa happens seamlessly and goes unnoticed by drivers. 

Lowest Additive Concentration 

Regardless of the season, gasoline contains detergent additives designed to keep fuel injectors and other fuel-system components clean.

Some automakers, however, think the additive content, called the lowest additive concentration (LAC), is insufficient for modern vehicles. It takes a low level of additive to pass the tests, and most gasoline on the market contains as little as 123 ppm of additive.

The low levels of detergent additives in modern gasoline allow deposits to build up on critical fuel-system components, and most motorists are unaware of how dirty the insides of their engines are. This provides a great opportunity to sell the benefits of AMSOIL fuel additives.

P.i.® and Upper Cylinder Lube

P.i. Performance Improver (API) is a potent, one-tank additive that deep-cleans your fuel system.

• Cleans fuel injectors, intake valves and combustion chamber deposits

• Reduces emissions and increases fuel economy up to 5.7 percent

• Use every 4,000 miles (6,437 km)

Upper Cylinder Lubricant (UCL) preserves and builds upon those gains. It also provides vital lubrication to the upper part of the cylinders. 

• Lubricates upper cylinders to fight wear

• Inhibits ethanol-related corrosion

• Keeps injectors clean

• Delivers 18 percent more lubricity than Lucas* and 20 percent more than Sea Foam* for better retention of horsepower and fuel economy.

For more information:
AMSOIL Fuel Additives.

AMSOIL Synthetic V-Twin Motor Oil Proves Superiority

AMSOIL EXCELS IN V-TWIN TORTURE TEST

• 2019 Harley-Davidson* Street Bob* • Milwaukee-Eight* 107 c.i. engine • 1,000 miles on engine dyno • 300ºF (149ºC) oil temperature • 421ºF (216ºC) max. cylinder temperature

Extreme heat is the biggest enemy for a powerful air-cooled V-twin engine, like those found on most Harley-Davidson* motorcycles. In fact, when designing its latest V-twin engine platform – the Milwaukee Eight* – Harley asked riders what they wanted from its newest engine. Two themes emerged: more power and less heat.

Extreme heat can ruin your ride

Some riders have complained about intense heat radiating from the engine while riding, particularly the rear cylinder, which doesn’t receive as much airflow as the front cylinder.

Extreme heat not only challenges rider comfort, it challenges the engine.

If, for example, heat causes the piston to expand beyond acceptable tolerances, it can rub against the cylinder wall and cause scuffing.

Heat also causes some oils to thin and lose viscosity. The oil can become so thin the engine loses oil pressure, causing the oil-pressure gauge to bottom out.

Riding conditions turn up the heat

V-twin heat becomes especially problematic when riding on hot summer days in conditions that limit airflow over the engine, such as in slow-moving parade or rally traffic. In extreme cases, the bike’s electronic temperature controls shut down the bike if it gets too hot.

Oil-cooled Milwaukee-Eight engine

Harley introduced its Milwaukee-Eight engine in 2016 in part to reduce extreme heat and enhance rider comfort. The engine uses a system of oil-filled cooling jackets surrounding the cylinders to reduce heat. The oil absorbs heat and carries it to a small oil cooler, where it dissipates into the atmosphere.

1,000-mile dyno test

To test AMSOIL Synthetic V-Twin Motorcycle Oil in the latest V-twin technology, we purchased a 2019 Harley-Davidson Street Bob equipped with a 107-c.i. Milwaukee Eight engine.

We instrumented the bike and rode it on the street to establish a baseline for “real-world” operation. This confirmed that low-speed, low-airflow conditions, like stop-and-go traffic, created the most challenging conditions.

We then installed the bike on the dyno in our mechanical lab and subjected it to a 1,000-mile test designed to simulate the worst-case conditions we saw on the street. One thousand miles is enough to make 640 trips down Main Street in Sturgis.

Airflow over the engine was restricted to hold the oil-sump temperature at a steady 300ºF (149ºC). Cylinder temperature topped out at 421ºF (216ºC). In these conditions, the oil can quickly oxidize (chemically break down), which causes the viscosity to increase until it’s out of grade and no longer provides the protection the engine requires.

Extreme heat no match for AMSOIL

Following the test, we chemically analyzed the oil to measure viscosity, oxidation, total base number (TBN) and wear metals. We also examined engine parts, in addition to the compensator, for wear or distress.

As shown, AMSOIL 20W-50 Synthetic V-Twin Motorcycle Oil (MCV) provided exceptional protection. The piston skirt contains virtually no wear, while deposits are minimal given the extreme conditions. In addition, the rings still move freely for maximum compression and power. The wear surfaces on the compensator are also in excellent condition, indicating the oil provided smooth, reliable shifts.

Rear-Cylinder Piston

The rings are virtually deposit free and didn’t stick for maximum compression and power. The skirt contains minimal scuffing for long engine life.

Compensator

The wear surfaces show minimal distress, indicating the oil protected the compensator for smooth, quiet shifts.

Oil analysis results are also impressive. The oil stayed within its viscosity grade despite the extreme heat. The oil limited oxidation and retained its TBN, which is a measure of its ability to fight corrosive acids. Finally, the oil limited wear metals to trace levels, indicating its excellent level of wear protection.

Click for larger image

For more information:

 AMSOIL Motorcycle Products

AMSOIL Racing Products Provided Exceptional Protection for Drag Racer

AMSOIL DELIVERS ‘SHOCKING’
PROTECTION IN DRAG RACING ENGINE

Preferred Customer and truck driver Paul Jordan of Butte, Mont. started racing a Junior Dragster at only 11 years old. At 14, he purchased a Plymouth* Duster,* which he’s dragraced since the early 2000s, competing in Montana, Idaho and the surrounding area. 

After 13 years of drag racing, the bearings in Jordan’s
Chrysler 408 showed virtually no signs of wear.

“A friend of the family talked my parents into bringing me out to the racetrack one day and from that point on I was hooked,” said Jordan. “I was only the second one in Montana to have a Junior Dragster at that point.” 

 

In 2007, Jordan built a Chrysler* 408 engine for his Duster. He used AMSOIL DOMINATOR® 15W-50 Synthetic Racing Oil (RD50) as the break-in oil and service fill.  

As you would expect, the engine constantly operates under severe conditions. It makes about 550 horsepower and regularly hits 5,000-6,000 rpm. 

Jordan estimates his Duster has made about 4,000 passes down the drag strip since 2007. 

“I’ve won five championships over the years, so I’ve made a lot of passes down a lot of tracks,” he said.

It uses six quarts of DOMINATOR Synthetic Racing Oil, a WIX oil filter as the primary filter and an AMSOIL Oil Filter as the secondary filter. Most notably, it has run on methanol fuel for the past three years, which is prone to attracting moisture and diluting the oil. 

“If you switch to methanol, the rule is you should change oil every other race,” said Jordan. Even so, he only changes oil once a year.

“There is no indication of any contamination,” said Jordan. “I look through it to see if there are any metal particles, but I’ve never had any. I probably could have put two years on the oil if I’d wanted to.”

He recently decided to tear down the engine for the first time since building it 13 years ago to refresh it, which typically includes installing new bearings, piston rings and honing the cylinders. He also wanted to make some modifications to increase power.

“I expected to open the engine, pull the bearing caps off and see a couple of them pretty much worn out and on the verge of failure,” said Jordan.

Instead, the inside of the engine looked clean and virtually free of wear. 

“It was pretty surprising when we pulled it apart, popped the bearings out and they looked nearly brand new,” said Jordan. “There’s no ridge at all on the cylinder walls, which is incredible. And I used to spray it with nitrous, too. The cylinders are in unbelievable condition. There are a few scuff marks, but nothing you’d expect for something that’s been abused for more than a decade. It was really shocking. And I can’t believe how clean it was; there was no buildup anywhere.”

Jordan said the crankshaft just needed to be re-polished. The car ran its best elapsed times at the drag strip in 2019, meaning it never lost power over the years.

“I could reassemble the engine as-is and go another 13 years,” said Jordan. “I have no reason to believe, other than AMSOIL, that the engine lasted as long as it did. I use AMSOIL in everything I own. I use it in my pickup truck, my semi, my race car...if AMSOIL made shampoo, I’d use that, too.” 

Jordan adds that he used AMSOIL Super Shift® Racing Transmission Fluid (ART) in the TF727 transmission used in the car from 2003 to 2017 without a rebuild.

“I truly appreciate the fine lubrication products offered by AMSOIL, and you can expect my loyalty for many more years to come,” he said. 

AMSOIL Racing Products

AMSOIL Limited Snowmobile Warranty

AMSOIL RUNS ON FREEDOM™
LIMITED SNOWMOBILE WARRANTY

AMSOIL Snowmobile Warranty

Don’t let the powersports manufacturers bully you into buying their brand of oil. You have the freedom to choose your brand of oil and keep your warranty intact.

To show our support for riders and to double-down on our confidence in our snowmobile oil, we offer the Runs on Freedom Limited Snowmobile Warranty. 

It covers engine repairs for two years or 5,000 miles (8,000 km), whichever comes first, on current model-year or newer sleds that use AMSOIL INTERCEPTOR® Synthetic 2-Stroke Oil exclusively.

Switching to AMSOIL products in your sleds will keep you Warranty Secure.

To get details and register, visit 

AMSOIL Warranty