Auto Repair Blog

Automotive Quiz for Informed Consumers

Automotive Quiz – Octane Ratings

What does gasoline octane rating mean?  Example 87, 89, 91 and 93 octane rating for gasoline.

  1. % of ethanol contained in the gasoline.
  2. % of detergents used to clean the engine
  3. Measurement of fuels ability to resist pinging or engine knocking
  4. % of lead ingredients added for better performance

This may look like a difficult question but most people know that the octane rating has something to do with the way an engine performs and the higher or lower the octane can either add too or detract from that performance. The correct answer to the gasoline octane rating question is C, measures the fuels ability to resist engine pinging and engine knocking. In a fuel injected or carbureted engine, the combustion ratio is the measured ratio between the volume of the cylinder and the combustion chamber at the top of the piston stroke and the bottom of the stroke. Engine pinging or knocking or what is commonly referred to as pre-ignition and is caused by the fuel and air mixture prematurely igniting. In most combustion engines 87 octane rating is sufficient to cause the engine to operate normally. Higher combustion engines in some high-performance vehicles tend to have higher than normal engine compression ratios and require higher octane rating gasoline. Putting higher octanes in cars requiring lower octanes does not increase the automotive performance of the engine. All manufacturers manuals will indicate the recommended octane rating for the gas that is appropriate for that specific engine. If pinging or engine knocking does occur, a higher-octane gas can alleviate the symptom but it is recommended that the vehicle be checked out by an experienced mechanic to determine the underlying causes. Muffler City Auto Repair specializes in diagnosing and repairing engine pinging and knocking. We employ only ASE certified mechanics with years of automotive experience. Foreign and domestic cars have specific engine standards that must be met for them to operate at peak performance. We have over 350 manufacturers certifications and can repair any aspect of an automotive problem. From transmissions repairs to brake replacement, from auto AC repair to engine rebuilds, Muffler City Auto Repair does it all.

Automotive Quiz – Tire Pressure

What is the recommended amount of air pressure tires need to perform properly?

  1. Same tire pressure in both the front and rear tires.
  2. Tire pressure listed on the sidewall of the tires
  3. 32 pounds per square inch or PSI.
  4. Different size tires have different PSI requirements.
  5. Manufacturers list correct tire pressure on door jams and in manual

Most car owners believe that all tires carry the same tire rating and even some garages put the same tire pressure in all 4 tires on most cars. The correct answer is that the manufacturer puts the recommended size and shape tire on the car when its delivered to the dealership. The manufacturer usually places the tire size and recommended tire pressure on the driver’s side door jam. So, the correct answer is E. But many car owners change tire sizes, shapes and the manufacturers tire brands that were put on the car at the factory. In those cases, the individual tires have a recommended PSI for each tire. Some manufacturers recommend that the tires in the back have higher pressure than the front, common on SUV’s. There is no one size fits all when it comes to the correct tire pressure. Tire pressures should be measured before the tires have had a chance to become warmed due to driving. Tires that are driven become warm from the road wear and the tire pressure increases as the tires heat up.  Correct tire pressure can not only effect road wear on the tires themselves but can also affect gas mileage, handling and automotive performance.

Why Choose Muffler City Auto Repair For all Your Automotive Needs?

Choosing the correct tire pressure for your cars specific tires is as important as choosing the right auto repair shop to repair and service your vehicle. With the explosion of used cars on the market today it’s no wonder that auto repair shops are springing up all over. But all garages are not the same. Many service garages offer only limited repairs for certain makes and for specific repairs. It is not uncommon to find radiator shops, auto AC shops, brake shops, or transmissions shops. Tire manufacturers like Goodyear and Firestone have started offering additional services other than their traditional tire repair and replacement. Choosing the right auto repair facility for your vehicle is a daunting task and should not be done merely on location or on price offered. Muffler City Auto Repair has been locally owned and operated by Ron Evans since 1995. His automotive vision was to provide Jacksonville and the North Florida area with expert muffler and custom exhaust system repair, design and fabrication. But being a Certified ASE mechanic meant that his expertise was far more than just providing excellent muffler service. So as Ron’s business grew so did his product offerings and today Muffler City Auto Repair is a full-service auto repair shop. We employ certified ASE mechanics that hold over 350 manufacturers engine repair certification. We can diagnose any mechanical problem your vehicle is experiencing and service all makes and models, foreign and domestic. Call Muffler City Auto Repair today for a pre-winter checkup and see what makes us different. Call Ron and his staff at 904-739-0091 or visit us on the web for a complete listing of our services and credentials at

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