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Should I Run Multi-Weight or Straight-Weight Oil in my Muscle Car?

Should I Run Multi-Weight or Straight-Weight Oil in my Muscle Car?

Ed Newman (Edited by Ches Cain)|

Mopar Muscle

Much of the stigma related to this has been eliminated due to technology.

Here’s the straight story on viscosity grade. The “W” number in, for example, a 15W-50 motor oil outlines the viscosity requirements of the oil when it is cold. This means that a 15W-rated oil has to meet certain criteria at cold temperatures. Taking our 50-weight example, a 15W-rated oil will flow more freely than a 20W-rated oil when compared at cold temperatures.

Winter weights have always confused people. Don’t be afraid of the W!

If you have a spec that calls for a 20W-50 but all you can find is a 15W-50, don’t sweat it. That just means it will have better flow at a lower temperature. Or as I tell people, at room temperature it’s closer to its operating viscosity than a straight weight. Or a 10W-30 is closer to it’s operating viscosity (30) than a SAE-30, and a 5W-30 is closer to its operating viscosity than a 10W-30. But the “W” is not the same type of number or scale as the 2nd number. A 10W-30 is NOT a 10 weight at one temp then a 30 at another!!  the 10W, or 20W is a totaly different test measuring toque absorbed at a given temperature range. The large number calculated is converted into the range which is your 5W and 10W and so on. A 0W is not a Zero Weight oil.

Now let’s talk about the “50” portion of a 15W-50, 20W-50 and straight SAE 50. The Society of Automotive Engineers (SAE) states that a 50-weight oil must have a viscosity at 100°C above 16.3 cSt but less than 21.9 cSt and have a high-shear-rate viscosity minimum of 3.7 at 150°C. This means that a 15W-50, 20W50 and SAE 50 weight must all meet these requirements. This does not mean they respond the same but they all need to meet these requirements regardless to have the 50-weight designation. Technically a 50-weight is a 50-weight at operating temperature no matter what the W designation is.

There is a LOT of confusion with these numbers. A little research will fix that.

Against this backdrop of understanding, the question is, should you run a multi-weight or a straight weight in our example? The answer is, take a close look at the oil specifications and compare to what you want to do and pick an oil that fully meets your needs. The best question to ask is, how does the oil hold up under shear”? Shearing is the loss of oil viscosity during operation. Shear is especially a problem when running engines at high RPMs.

Now no matter the age of the engine, when you use a straight weight oil there is some risk based on the quality of the brand. Outside of the normal operating temperatures, any degree below  – lets say 75 degrees Fahrenheit, the oil will rapidly increase in viscosity. Starting an engine with a oil lacking the ability to flow as well as another also increases the likely hood to shear.  Multi-viscosity oils solve this issue. And these days, the lower the “W” test value, the more advanced the product.

Consider what determines quality at various levels

The quality of the motor oil brand determines how many cycles under stress the motor oil can withstand before sheering out to a undesired viscosity. In some of these companies, the quality of the additives is determined by the profit margins demanded by the stockholders. (AMSOIL by the way, has no stock holders.)

Typically, muscle car folks will have a tendency to run up the rpm from time to time, which can shear down the oil viscosity. Viscosity is one of the most important factors for overall engine protection. When oil viscosity at operating temperatures degrades significantly, engine protection will be compromised. On the other side of the coin, if you start and run your muscle car in colder climates, a multi-weight will definitely provide more oil flow to critical parts quicker. Remember, most engine wear on automobiles actually occurs on startup when engine oil is not flowing readily to engine components.

So there are applications for straight weight oils but automotive engines are no longer in that category. Take advantage of the reduction of stress multi-viscosity oils offer. Muscle car owners want to feel the power at the wheels and a smooth engine. You want the oil to be optimum at all temperature ranges and even after a long trip.

Viscosity selection tip: pick a multi-weight oil that has outstanding shear stability. I personally always recommend AMSOIL.  – The one motor oil with a guarantee to stay in grade!

By the way =

A Look at Today's Gasoline Issues and Quality

A Look at Today's Gasoline Issues and Quality

Gasoline is the source of your vehicle’s power – and many of its problems.

Gasoline quality is vital, yet often overlooked.

Dan Peterson - AMSOIL Technical Development

AMSOIL’s Dan Peterson.


Gasoline’s influence on our lives can’t be overstated. Remember how the gas lines of the 1970s disrupted daily life? People waited hours to fill up – if there was any gas available once they finally pulled up to the pump. Odd-even rationing dictated that motorists could only fill up on even-numbered days if the last digit on their license plate was even. The fallout of the gas shortages of the 1970s was a driving force behind the government mandates to increase fuel efficiency that continue to influence the industry today.

A few years ago, when gas hit $5 a gallon in some places, stories populated the Internet and airwaves about people willfully losing money to sell their giant SUVs in favor of small, fuel-efficient cars. Some people even took a loss on their houses in the suburbs to move closer to work.

In many ways, gasoline makes the world go ‘round, yet many of your customers likely know almost nothing about it, including the negative effects it can have on their vehicles.

Gasoline is distilled from petroleum crude oil. Typically, a 42-gallon barrel of crude will yield about 19 U.S. gallons of gas. The final blend can contain hundreds of different ingredients, among which are detergency additives designed to prevent harmful deposits from forming inside your engine.

In 1995, the EPA introduced its minimum gasoline detergent standard, known as lowest additive concentration (LAC). The intent was to ensure that all gasoline available in the country contained sufficient detergent additives to combat formation of deposits that reduce fuel efficiency and performance.

The widespread use of electronic fuel injection in the 1980s was a driving force behind the introduction of the LAC mandate. It quickly became evident that fuel injectors were especially sensitive to deposits, and the gasoline of the time didn’t contain sufficient detergents.

Deposit formation on the injector tips disrupts the spray pattern, which reduces fuel economy and results in less-efficient combustion. This contributes to increased tailpipe emissions since unburned gasoline can escape the combustion chamber on the engine’s exhaust stroke.

Deposits can also form on the intake valve, piston crown and in the ring grooves. They can prevent the intake valve from closing completely, reducing engine compression and horsepower. Deposits in the ring grooves can lead to ring sticking, which also reduces engine compression since a stuck ring won’t seal the combustion chamber completely. Piston crown deposits act like a sponge that soaks up gasoline. This can result in preignition, where the fuel/air mixture ignites sporadically, reducing performance and potentially damaging the engine.

Many automakers today don’t think the LAC mandate goes far enough. In fact, many gasoline marketers have reduced detergent levels by up to 50 percent, according to www.toptiergas. com. TOP TIER Detergent Gasoline is a performance specification designed by several of today’s top automakers.

Today’s vehicles run even hotter than they did in 1995. Since then the number of engines that use turbochargers, which increase heat, has grown substantially. So, too, has the number of vehicles that use direct fuel injection, which locates the injectors directly in the combustion chamber, exposed to intense heat. Plus, injectors today are more highly engineered with tighter tolerances, meaning even minute deposits can interfere with performance.

Gasoline is the source of your vehicle’s power – and many of its problems if you don’t perform proper maintenance. We formulate AMSOIL P.i.® to be one of the most potent additives on the market. It contains a very high dose of fuel detergents proven to combat the problems associated with gasoline, keeping injectors clean and functioning properly. In fact, testing showed dirty injectors returned to >95 percent flow after only one tank of gas treated with P.i. Just take a look at the dramatic before/ after images above.

As vehicles become more sophisticated and sensitive to gas quality, make sure you understand the importance of maintaining them with a quality fuel additive. AMSOIL provides solutions to problems you may not even be aware of.

Let AMSOIL Sioux Falls be your gasoline fuel additive source! Depend on us for the best products which will always be the state of the art for all Nebraskans! Thank you for your business. We love being here in Sioux Falls!

ECHO String Trimmer Technical Study

ECHO String Trimmer Technical Study

AMSOIL SABER® Professional Synthetic 2-Stroke Oil resisted performance-robbing deposits and maintained power and performance in ECHO string trimmers.

Published September 2016

Overview Government mandates require modern handheld trimmers and other twostroke equipment to produce less exhaust emissions. To comply, some original equipment manufacturers (OEMs) design their equipment to run on leaner fuel/oil mixtures. Burning more air and less fuel/oil, however, also increases heat. To withstand this intense environment and ensure equipment lasts as designed, modern two-stroke oils must demonstrate improved wear protection and detergency. Objective Demonstrate through lab testing that the latest generation** of AMSOIL SABER® Professional Synthetic 2-Stroke Oil exceeds the increased performance needs of ECHO* string trimmers in particular, and modern two-stroke string trimmers in general. Methodology Testing was conducted on eight ECHO trimmers in the AMSOIL mechanical lab and followed a test plan designed to compare two-stroke oils in simulated real-world conditions. Test duration is designed to simulate an extended length of service. The OEM’s recommended 50:1 mix ratio was followed.


SABER Professional was installed in four trimmers and ECHO Power Blend was installed in another four. Computer-controlled actuators operated the trimmer throttle triggers according to an identical protocol for each unit. Images of trimmers arranged on the test stand are included for reference.



Test administrators monitored engine rpm, spark-plug temperature, exhaust emissions and other parameters to ensure consistent, repeatable operation and gauge overall performance of each trimmer. After 300 hours of operation, the trimmers were disassembled and inspected. Note: Test results published in this Technical Study describe and represent properties of oils that were acquired on the dates listed in Table 1 on the facing page. Results do not apply to any subsequent reformulations of such oils or to new oils introduced after completion of testing. All oils were available to consumers at the time of purchase. Testing was completed in July 2016. The differences in effects between AMSOIL SABER Professional and ECHO* Power Blend* are statistically valid at the 95% confidence interval for exhaust port blockage and spark arrestor screen plugging.  The carbon buildup on pistons was not numerically quantified as part of the study.

Weed trimmer ready for engine testing

The test was run using two engines for each treatment. The study was then replicated using the same n=2 design. Exhaust- port blockage and spark-arrestor screen plugging were compared using a paired t-test. Equipment was run at factory-set conditions and there was no effort to intervene on any problems developed by the equipment outside of recommended maintenance in the owner’s manual. String trimmers arranged

Piston Rings/Piston Skirts

Deposits in the ring grooves can cause the rings to stick and lose effectiveness. Engine rpm can decrease and the engine cab lose compression. Significant compression loss leads to engine failure. Heavy deposits on the piston skirt increase friction and reduce performance.

Piston ring deposits with ECHO and AMSOIL

Deposits appear heavier on the pistons lubricated with ECHO Power Blend. The pistons lubricated with SABER Professional appear cleaner. SABER Professional provided improved detergency and extreme-heat resistance. Both oils guarded against piston ring sticking well.

Piston Crowns/Undercrowns Heavy piston crown deposits can cause preignition and poor performance. While undercrown deposits are unlikely to impede performance, they are an indicator of the oil’s detergency properties. With modern two-stroke equipment running hotter, oils must demonstrate strong detergency and heat resistance to maintain piston cleanliness and peak performance.

piston crowns undercrowns deposits from Echo oil

Pistons lubricated with ECHO Power Blend appear to contain heavier crown and undercrown deposits. In contrast, the piston crowns lubricated with SABER Professional look clean, with low levels of deposits. SABER Professional provided improved detergency and extreme-heat resistance.

Wrist Pins & Bearings The wrist pin and bearing are exposed to extreme heat due to their proximity to the combustion event. Ineffective lubrication can result in deposits, polishing and flat spots on the wrist pin restricting rotation. As the engine works to overcome this restriction, the piston can bear increased pressure, leading to scuffing and eventually failure.

wrist pins

All eight wrist pin bearings demonstrated no issues throughout the test, indicating the oils provided good protection. None of the wrist pins contain flat spots. Both of the oils performed well in this area.

Exhaust Ports

For the engine to run properly and produce maximum power, exhaust gasses must flow freely out the exhaust port during operation. Restricted exhaust causes RPM and power loss, starting difficulties and eventually, failure to operate.

Exhaust ports

SABER Professional demonstrated low exhaust-port deposits. In contrast, all four exhaust ports on the engines using the ECHO product suffered blockage, with two more than half blocked with deposits.

Note: Airflow loss was calculated using a flow bench to measure restriction which was converted to a percentage of flow compared to an unblocked exhaust post.

Spark Arrestor Screens

Exhaust gasses continually flow through the spark arrestor screen located on the muffler which is prone to plugging. Like the exhaust ports excessive deposits on the spark arrestor screen restrict airflow and reduced power.

Spark arrestor screens

SABER Professional demonstrated low spark-arrestor screen deposits. In contrast, screens on the trimmers lubricated with the ECHO product contained higher levels of deposits. The screen from engine 5 was nearly completely blocked with deposits after 239 hours of the 300-hour test and required replacement. On average screens from engines using ECHO Power Blend suffering 4X more airflow loss than screens on engines using SABER Professional 2-cycle oil.

Note: Airflow loss was calculated using a flow bench to measure restriction which was converted to a percentage of flow compared to an unblocked spark arrestor screen.

Main Bearings

The main bearings receive little lubrication given their location in the lower end of the engine. Deposits are an indicator of poor oil detergency. Heavy deposits can restrict bearing rotation and eventually lead to failure.

Echo main bearings

The bearings lubricated with SABER Professional appear to contain fewer deposits.


Oils with ineffective detergency properties can allow deposits to accumulate in the crankcase. During operation, deposits can circulate throughout the engine and reduce performance.

crankcase housing Echo

Crankcase deposits look heavier in the engines using ECHO Power Blend. The engines using SABER Professional appear clean and free of harmful deposits.

RPM & Spark-Plug Temperature

Reduced rpm and spark-plug temperatures are indicators the engine is producing sub-optimal power. This can be caused by heavy exhaust port and spark arrestor screen deposits which restrict air flow through the engine and result in reduced power. The following graphs depict the average rpm and spark-plug temperature of engines at wide-open throttle using SABER Professional and ECHO Power Blend.

Engines using SABER Professional maintained consistent power throughout the study, while the average spark-plug temperature declined slightly. In contrast, the engines using ECHO Power Blend slowly lost power as the study progressed. Similarly, the average spark-plug temperature suffered a drop.

RPM curve Echo string trimmer


As demonstrated in lab testing designed to simulate a full season of real-world use, AMSOIL SABER Professional Synthetic 2-Stroke Oil provides excellent protection for ECHO* brand string trimmers. SABER Professional outperformed ECHO Power Blend* XTended Life* Universal 2-Stroke Oil by providing improved resistance to piston deposits, crankcase deposits and exhaust port blocking. Due to its ability to limit exhaust-port and spark-arrestor-screen deposits, SABER Professional protected against rpm loss 21 percent better, resulting in reliable operation. The latest generation of SABER Professional meets or exceeds the increased performance requirements of ECHO SRM 225 trimmers.

AMSOIL fully supports the use of SABER Professional as a replacement for ECHO Power Blend XTended Life Universal 2-Stroke Oil, and warrants its use according to the AMSOIL Limited Liability Warranty (G1363).

Fall is already here – It´s time for an oil change

Fall is already here – It´s time for an oil change

Hey Sioux Falls, It’s Fall Oil Change Time


For those of us who love taking care of our vehicles, falling leaves and dropping temperatures signal the time for an oil change. Prepare your vehicle for winter with AMSOIL Signature Series Synthetic Motor Oil. Its superior performance helps you take engine protection to the next level. While you’re at it, become an AMSOIL Preferred Customer today and save. Outstanding protection for your vehicle and perks for you. What’s not to love about fall?

Are you preferring the Amsoil oils? You can buy them all in the Sioux Falls store at 12th &G.

Or use this Online link to the Amsoil sales page if you are outside of the area.

Deposit protection is critical for turbocharged engines

Deposit protection is critical for turbocharged engines

Motor oil quality must stay ahead of the curve.


It may be a good time to invest your retirement funds in a company that builds automotive turbochargers; they’re predicted to be in most new passenger cars/light trucks by 2020.

Matt Erickson AMSOIL INCAs such, we’ve focused quite a bit of time and energy on turbos and the challenges they present to motor oil. Today, I want to dive a little deeper into turbo tech and explain how they work and why AMSOIL will be synonymous with the subject of turbos in the coming years.

An engine is essentially an air pump, and the more air it ingests, the more fuel it can burn – and the more power it can produce. There are a few ways to increase the amount of air the engine takes in, but turbocharging has emerged as the favored choice of automakers.

As shown in the diagram, exhaust gases commonly exceeding 1,000ºF spin a turbine, often at more than 150,000 rpm, which drives the compressor that draws ambient air used to pressurize the combustion chamber. The added oxygen combined with direct injection and advanced engine-tuning helps the engine burn fuel more efficiently, boosting fuel economy. It also allows the engine to burn more fuel for increased power. As a result, a turbocharged four-cylinder engine can make as much power as a non-turbo six-cylinder engine. This advancement allows automakers to build vehicles with smaller, lighter engines that don’t sacrifice power or torque. Motorists enjoy the performance and fuel economy they demand, while automakers meet increasingly strict CAFE (Corporate Average Fuel Economy) requirements. A win-win situation.

As they say, there’s no such thing as a free lunch, and in this case, it’s the motor oil that ends up footing the bill. The turbo’s center section contains an oil-lubricated bearing. The tremendous heat and stress turbos create can cause some oils to break down and form harmful bearing deposits, known as turbo coking. Over time, turbos can suffer reduced performance, or fail altogether.

For this reason, auto manufacturers and oil companies – including AMSOIL – automatically include turbocharged vehicles in their severe-service category when prescribing oil-change intervals. The TEOST 33C Test (ASTM D6335), an industry-standard bench test that simulates turbocharger operating conditions, has taken on added importance in today’s automotive landscape. With the predicted rise in turbo use, it’s more important than ever for motor oils to protect against harmful high-temperature deposits to keep vehicles running properly. To meet the API SN Resource Conserving and ILSAC GF-5 motor oil specifications that are often recommended by vehicle manufacturers, a 5W-30 motor oil must limit total deposit formation to 30 mg or less in the TEOST Test.

Turbocharger Cutaway

In our recent published tests (deposits caused by lower quality base stocks in turbo equipped engines), AMSOIL Signature Series 5W-30 Synthetic Motor Oil held the total weight of deposits to 7 mg, well under the 30 mg limit required by the API and ILSAC, while Royal Purple® API 5W-30 and Mobil 1® Extended Performance 5W-30 came in just under the limit at 25.4 mg and 28.2 mg respectively. Signature Series 5W-30 Synthetic Motor Oil protects against harmful deposits on turbochargers 4X better than Mobil 1® Extended Performance and 3.6X better than Royal Purple® in industry-standard testing*.

We want our customers to understand the importance of protecting their turbocharged vehicles, and to know AMSOIL is devoted to offering protection beyond what is required by the industry. We are the only name for true automotive enthusiasts here in Sioux Falls!

*Based on independent, third-party testing of AMSOIL® Signature Series 5W-30, Mobil 1® Extended Performance 5W-30 and Royal Purple® API 5W-30 in the ASTM D6335 bench test required by the API SN Resource Conserving specification. For full test details visit