Premium vs. Regular gas for 2005 Lincoln LS?

Question

Can I use regular gas instead of premium gas in this car? am I risking damage to the engine if I use regular gas though the mfactur. recommends premium?

Answer 1

If a manufacture says the car requires premium gasoline, you must put premium gasoline in the vehicle. If it recommends premium, then you can use the regular stuff.

Let me explain...

The reason for requiring premium is because the engine is designed to be a performance engine. This usually means that the engine has a high compression to give your better performance and power.

However the higher compression also requires you get gasoline that does not pre-ignite, or believe it or not more resistant to spontaneous ignition. This means you'll need a higher octane (more resistant to ignition).

The lower the octane number, the easier the gasoline will ignite. Which means if you put lower octane in a high compression engine, you'll get something called pre-ignition or spontaneous ignition. This basically will generate a flame front that is at various points in the cylinder that is not at the location of the spark plug, where the desired igntion point is.

Usually pre-ignition occurs where the piston and cylinders meet. This means it will generate a flame front that is opposing the flame front from the spark plug when it ignites. (This will also cause loss of power)

When this occurs as the flame fronts meet (the ones from the cylinder walls due to pre-ignition, and the ones from the spark plug), you'll get a shock wave generated. The shock waves over time will cause piston and cylinder/head damage, typically seen as pitting.

What is normally heard from drivers is commonly described as pinging/knocking, and the damage that can occur will void a warranty.

You can always try a lower grade of gasoline, but if you hear noise coming from the engine, you'll understand why. If you don't hear noise from the engine, you might be safe. Some vehicle manufacturers understand that people want to save a few bucks and so they add a knock sensor that retard's spark. This lowers engine compression simply by retarding spark to a less than optimal point. Honestly to me it seems like a waste to do this. If you're buying a high performance vehicle. typically premium is only $0.10 more per gallon than regular, which means on a 15 gallon tank, you're paying only $1.50 more. The savings in engine wear and tear is well worth the extra $1.50 a tank.

Answer 2

Yes you are risking damage. If the manufacturer reccomends premium you really do have to use it. If you don't you risk the engine pulling timing, which will decrease power and fuel economy. Also you run the risk of engine knock which can damage and even bend connecting rods.

Octane rating is the rating of how resistant the fuel is to combustion. 87 octane actually burns easier than 93.
The reason for this is that in a high performance engine, the air/fuel mixture is put under much higher pressure and temperature than in a normal engine. If you use 87 octane, the mixture could actually ignite while the piston is still going upwards, well before the spark plug goes off. This is because it is under so much pressure and high temperatures that it reaches it's flash point. The result is that the piston has to fight the explosion as it travels upwards. When the spark plug goes off, the fuel is already spent and most of the power has been wasted.
High octane fuel is resistant to this sort of early combustion. It's actually harder to burn this fuel. That helps to ensure that it will only ignite when the spark plug goes off at the proper moment.

High octane gas is not refined more, it's not really cleaner or more powerful. It just has different properties.

Answer 3

Mom, The only and I mean ONLY difference between regular [what your car needs] and premium is that premium contains additional anti knock compounds required in high compression engines, which yours is not. It does not burn cleaner, make more power or benefit your engine in ANY WAY. You have bought onto an urban myth. Buy the regular. Your car will like it. Don't simply take my word for it. Google "Octane" and do some reading. You'll find you have been wasting money all along based on a false assumption.

Answer 4

Use the manufacturer's recommendation. The grade of gas denotes how much the fuel has been refined. Higher grades of gas (92,93) have been refined more than 87. The engine has been specifically tuned and programmed to use a certain grade of fuel. Providing a lower grade will give you lower performance and may cause the car to not run as well. Using a higher grade will only create more exhaust emissions and waste your money.

The price hurts, but not as much getting your injectors cleaned or replaced a few times a year.

Answer 5

That pinging you hear when you use regular is parts of the engine smacking into other parts of the engine. Stick with what the manual says.

Answer 6

yes you can damage it, use what is resommended.