The CNG Project

Introduction to a New Ongoing Series

After months of planning and parts sourcing I am finally at the point where I am ready to begin a new project. This will be the conversion of my Lexus to CNG.  As you may or may not know, CNG stands for compressed natural gas. When I am done with this project I will be able to run the engine on either gasoline or CNG. The engine will be able to switch back and forth between the two whenever necessary.

The car being converted.

The reasons for doing this conversion are many. Some of these things are related to the advantages that CNG provides over gasoline; I have written on this subject before. On the practical side, CNG at the local station where I live goes for about $1.25 per gallon compared to the September 2011 price of gasoline at $3.52 per gallon. Obviously CNG is cheaper but more than that the price is also stable so a year from now it will be about the same, and if some crack pot dictator in the Middle East goes on a terror the price of natural gas will probably still be about the same.

The cost of the conversion is obviously steep if it is to be done correctly. Many people out there are doing conversions incorrectly and bragging that they can do it for between $1000 and $1500 dollars for the parts, and then mix in some free labor performed by themselves and they think they are good to go. The problem is they are using inferior systems with inferior parts. They will say that it doesn’t matter as long as the system works. The problem is that they usually end up with a system that will make their engine run but it will never run right. They will have problems with check engine lights coming on all of time, or the vehicle will lack power so badly that it’s almost not even drivable.

CNG fuel regulator, reduces the pressure from
3600 psi before sending it to the injectors.

A good conversion should not compromise performance in any way, shape, or form. Engine power should be about the same whether running on gasoline or CNG. Fuel economy should be the same on both fuels as well, and you should never have to deal with a check engine light coming on when the vehicle runs on CNG. The check engine light illuminating is an indication that something in the way the engine is running is not right. A quality CNG kit and conversion should allow the engine to run exactly as the engineers intended except on natural gas instead of gasoline. Some of the fly-by-night companies out there that are selling bogus CNG hardware will actually tell you that you should buy a cheap code reader in order to erase codes as they pop up.

Another thing that is important to know about CNG conversion is that these systems run at very high pressure, up to 3600 psi. In order to do the conversion in a way that is safe some training is required. Certain safety standards exist in order to keep these systems safe and it is important that these standards are followed closely by the individual performing the retrofit. I am a certified CNG fuel system inspector so I know the standard and obviously I intend to adhere strictly to the code.

Numbers

So what kind of cost savings will I see and how long will it take to recoup my costs? To fill the CNG tank on my car it will take about $9.00. This fill will give me about 180 miles before the tank must be filled again. This means that I will be spending about $.04 per mile. To run the car on gasoline it costs about $.13 per mile. If I drive the car 15,000 miles per year which is fairly average for the run of the mill car in the U.S. and if gas prices stay the same, I will recoup my cost in about 2.8 years. If gas goes back up to $4.15 per gallon like it was here back in 2008, I will recover the cost in about two years. If I drive more miles per year I will recover the cost sooner, and if gas goes to something never seen before, then there is no telling how fast I will recover the cost.

Saving money on gas is only one of the reasons that I am doing this. I am also doing this for purposes related to research and some things that I have going on related to my occupation as a college auto instructor. The last reason is I am doing this for fun. Most car guys spend money building some kind of custom 4X4 or restoring classic cars and such. I am kind of a geek as well as a car guy, so I am spending time and money building an alternative fuel vehicle.

The Hardware

The car is a 2007 Lexus ES300. This is kind of just a regular midsize sedan with 3 liter V6. The reason that I chose this car is because I got a good deal on it. I was looking for a midsize Honda or Toyota sedan to do this conversion. Since Lexus is built by Toyota the car that I am using will be just fine. The ES300 is actually just a fancy Camry so I pretty much got what I originally set out to get. Being a sedan and having a trunk is important because that is where the tank will go. You could really put the tank just about anywhere inside the vehicle that you want. You could even put it on the roof if you really wanted to.

The electronic control unit that runs the CNG system

The CNG fuel system parts come from Technocarb. This is a company out British Columbia Canada. They make several different kits from parts that are of Italian origin. I have friends that are into CNG conversions that have had very good luck with hardware from Technocarb. The kit is a multiport injection setup which is the most effective. A separate injector will feed each individual intake port which makes for more precise air/fuel metering. Some of the cheap junky kits use what is called a fumigation setup. This just floods the entire intake manifold with natural gas and it is not very precise.

CNG injectors. One set of three for each side of the engine.

The kit from Technocarb will require tuning and customization once it is hooked up in the vehicle. This is one of the things that makes the Technocarb setup nice. Software and a laptop computer are required to interface with the CNG computer to dial it in and make the vehicle run nicely. This also makes the Technocarb kit the kind of thing that someone without any knowledge of fuel control systems would not want to install themselves.

The CNG tank is the most expensive part of the conversion. A few different style tanks are available, but some are not practical for use in a normal sedan because they can be too heavy. The market for CNG tanks is also flooded with all sorts of used tanks pulled from wrecked vehicles and other places. Some of the used ones are good and some are not. Every tank has an expiration date on it and once that date passes the expiration date, the tank cannot be used again. Many of these expired tanks are out there on the used tank market. Some of the used tanks might be damaged as well, so buying a used tank is not ideal.

I purchased a new type 3 tank from a company in Calgary, Canada called Dynetek. The type 3 tank is very light because it is made of mostly carbon composite. Besides being very light and durable, the tank is also a 3600 psi tank. Running the system at 3600 psi is ideal because it increases the range of the vehicle. Many of the older used tanks are only 3000 psi tanks. This new tank from Dynetek is also a 20 year tank. That means that I will be able to use it until 2031. Many new tanks are only good for 15 years.

The CNG tank. This tank holds about 7.5 gasoline gallon equivalent.

What Now

Over the next few weeks or months, depending on what happens with my schedule, I will be installing these parts in the vehicle and hooking everything up. As I go through it I will take pictures and make some notes. Periodically I will write a bit about how the project is going and the things that I have learned. Once it is all finished we will know how it all works out, and I intend to test things such as real world fuel economy as well as power output on gasoline compared to power output on CNG. This should be fun and interesting.

The Best Cars Ever: Toyota Corolla

Another Entry in the Ongoing List of Amazing Cars

1968 Toyota Corolla

In 1968 Toyota introduced a new car to the U.S. market that like other cars in the Toyota line up used a version of the word “crown” for its name. Toyota first came to the United States in 1958 and the first sedan they had to offer the American market was called the Crown. This car didn’t sell very well and after a few years was discontinued. The Next sedan released in the U.S. was the Corona. This is the Latin word for crown. This car sold very well and in 1968 Toyota introduced the Corolla which derives its name from the Latin word for small crown. The Corolla was essentially a smaller version of the popular Crown.



2000 Toyota Corolla

 Today the Corolla is the longest running “import” sedan sold in the United States (the longest running model from an import company sold in the U.S. is the Toyota Land Cruiser which came to the U.S. on the first boat from Japan when Toyota arrived on our shores in 1958). Globally the Corolla has sold more units than any other car ever, including the old Volkswagen Bug. Estimates show that a Corolla is sold somewhere in the world every 40 seconds. Nearly 40 million units have been sold world wide since it was first introduced.

The Corolla has been used as a basis for many different cars. The Geo/Chevy Prizm, the Chevy Nova from the 80’s, the Toyota Matrix, the Pontiac Vibe, and the Scion xD have all come from the Corolla. The Corolla has been sold in rear wheel drive, front wheel drive, and 4 wheel drive configurations. Over the year there were 4 door sedans, 2 door coupes, and 3 and 5 door hatchbacks, there was even a few different station wagons. The only configuration that has not changed over the years is that the engine has always had 4 cylinders. The current Corolla is the 10^th generation and is always found in list of the top 10 best selling cars in the U.S.

Popularity and manufacturing longevity do not make this car great; the thing that really makes it great is that it is so darned reliable. Not very many cars come close to matching the reliability of the Corolla, no other model in the Toyota lineup can claim to be better built than the Corolla. Anyone who has ever owned one of these cars knows exactly how it is, and probably has a story about how amazingly trusty their Corolla was or is. Some of them become very ugly and beat up but they still run well and they still drive solidly down the road. It’s one thing to have a car go hundreds of thousands of miles with the original engine and transmission, but it’s another thing to be able to remain a solid ride despite some rust, dents, and faded paint.

The Corolla is not offensive to look at, but it has never been anything special in its form. The car has never been slow compared to other cars in its class, but it has never been a sports car either, although there have been some models that were rather sporty. Back in the late eighties there was a rear wheel drive coupe version referred to as the GT-S that was sold for a few years despite the fact that all other models were switched to a front wheel drive layout several years earlier. These old GT-S coupes are still highly sought after by some Toyota enthusiasts. There was also a model referred to as the FX-16 that was a sporty hot hatch, which is interesting because this was back in the days before there was really such a thing as a hot hatch.


1986 Corolla GT-S



1987 Corolla FX16

For most people out there things such as looks or sportiness are not the least bit important when their car is broken down on the side of the road. The car that doesn’t leave you stranded is the car that you have a hard time learning to hate. People who don’t like the Corolla will always comment on their dislike of superficial things such as looks or they will claim that the car is not fun to drive. What car in the same class as the Corolla can be classified as a driver's car? Is the Corolla some what plain? Perhaps but it is at least as good if not better than any other car in it's class when it comes to aesthetics? Also, there is nothing wrong with viewing a car as an appliance, or a simple tool of transportation. To most people, that's all a car is anyway.

2011 Corolla

Two words that sum up the reason for calling the Corolla one of the greatest cars ever are, “time tested.” After these many decades the Corolla has proven itself to be reliable, solid, safe, and efficient transportation, getting people from point A to point B without any fuss. This is the kind of reputation that many auto manufacturers wish they had for their transportation offerings, such status cannot be purchased by any corporation. The Corolla is solidly one of the best cars ever… no pun intended. 

The Latest Line on Brake Linings

For all of you that are adventurous enough to do a little work on your own car. One of the things that you might have tried, or may be willing to try is replacing your own brake pads. In many cases the hardest part of replacing your brake pads comes during that moment that you are standing at the parts counter at your friendly neighborhood auto parts store. After they look up your parts based on make and model, they will usually ask you what kind of pads you prefer.

You might answer this question by telling them that you want the new kind of pads. Of course this goes without saying. What they are referring to is the composition of the friction material used in the pad. Not all pads are equal, and just because they fit on your car doesn’t mean that they are the best thing for it. Your choices are usually semi-metallic, organic, or ceramic, but there are a few more choices for some makes and models.

Semi-metallic pads are the cheapest, and last a long time. They are composed of a material that contains ground up bits of metal. Semi-metallic pads used to be the most commonly used pads but they have some drawbacks. The biggest drawback is that semi-metallic pads are much more likely than the others to develop a squealing noise. This might be just a minor chirp as the wheels come to a stop or it could be a major howl that emanates the instant the brake pedal is touched. Either way it can be very annoying. Semi-metallic pads are also harder on brake rotors and have more of a tendency to wear the rotors down.

Organic pads are made from materials that are usually carbon based. Sometimes they are referred to as synthetic pads. They are a very common pad of choice for smaller vehicles because of they way they wear. Organic pads used to use asbestos as a primary component in the friction material. Asbestos was very good at withstanding the heat, and providing nice smooth braking feel, but it is a known carcinogen and was fazed out decades ago.

A common component in organic brake pads today is Kevlar. Organic pads are good because they are very quiet compared to semi-metallics and they are easier on the rotors. The biggest problem with organic pads is that they wear much faster than any of the others. Sometimes organic pads can be worn out in as little as 20,000 miles. They do not take abuse very well. They also produce a fair amount of break dust that will build up on your bling rims.

The third type of pad and the one that might be the best is the ceramic brake pad. These pads are composed of a material that is made up of ceramic fibers, copper, and bonding agents. These pads last a long time, dissipate heat very well, and don’t produce very much dust that accumulates on the wheels. They are also very quiet, or at least it would seem so to humans. The vibration of the pads in the calipers that becomes the noise that we hear, vibrates at a frequency that human ears cannot hear. If the noise can’t be heard, is it really making a noise? Do the dogs in the neighborhood appreciate all of this noise?

The biggest problem with ceramic pads is that they are expensive. Often times they will be 3 times more expensive than semi-metallic or organic pads. A normal set of semi-metallic pads might run $15 to $20, where as a set of ceramic pads for the same vehicle might be $50 or $60. Considering how much better ceramic pads are, the cost should not be prohibitive. Remember we are talking about a very important system on your vehicle. The difference between $15 and $50 is not the same as the difference between $100 and $300 dollars so spending three times more on brake pads is not as painful on the wallet.

The other things that you usually get with the more expensive pads are things such as new shims, and new anti-rattle clips and springs. Replacing this hardware is a good idea even though it may not be totally necessary. Both of these things will help to keep the pads quiet.

Ceramic brake pads can be hard on brake rotors but considering brake rotors are getting much cheaper to replace, the amount that pads wear down the rotors, doesn’t matter as much anyway.

Disc brake quiet applied to the back of the pad and not to the friction
surface on the bottom.

Another type of pad that is out there but maybe not so common is the full metallic type. Metallic pads are made from pulverized metal particles formed into a block and attached to a steel plate. These are very tough but they are only effective when the brakes get hot and they make a tremendous amount of noise. These are probably best suited to using on a race car rather then on the family minivan (not that you could even get any that would fit your minivan).

If you find yourself in the parts store buying brake pads and they ask you which ones you want. Go for the ceramic first, the organic second, and if neither one of those are available don’t bother with the semi-metallic and just go to another store. When they try to sell you the small packets of goo that goes on the pads, it’s not a bad idea. Just don’t put the goo on the friction surface of the pad, it’s supposed to go on the steel backing plate of the pad. This helps the pads to keep from vibrating in the calipers which causes a squealing sound. Never be afraid to spend a little extra when doing your brakes, in the end it will likely be worth it.

Says One Thing, but It’s Really Something Else

With the global economy being what it is, every car on the road is made up of bits and pieces that come from all sorts of companies all over the world. Many cars are exactly the same under the skin because they are made in the same factory by the same company. Sometimes these cars carry nameplates that that are part of the same corporate family. Sometimes one vehicle platform may carry nameplates from two or three different corporations. Through some joint operating agreement all companies sell slightly different versions of the same vehicle.

The biggest reason for doing this is to save money. R&D of any new product is very expensive and time consuming. Many times they will use this “badge engineering” to produce vehicles that appeal to different demographic groups. Sometimes one manufacturer will lack expertise in one area so they outsource the design or development of a particular model to another company that is really strong in that area.

The following is a list of some of the major manufacturers and the makes that fall directly under their corporate umbrella:

General Motors builds Chevrolet, Buick, Cadillac and GMC. In the last few years they have gotten rid of Pontiac, Saturn, Hummer, and Oldsmobile.

Ford builds Lincoln, and Mercury was done away with earlier this year.

Chrysler, Dodge, and Ram are currently owned by Fiat of Italy, before that they were owned by Mercedes. Look for Fiats rebadged as Dodges on the US market soon. Fiat also owns Ferrari so if we are really lucky maybe we could get a Dodge with a Ferrari engine in it. Don't hold your breath.

Toyota builds Lexus and Scion

Lexus ES350 (top), and the Toyota Camry (bottom) are the same car
with different headlights, taillights, and trim.

Honda builds Acura

Nissan is owned by Renault and also builds Infiniti

Hyundai owns Kia

BMW builds Mini and Rolls-Royce

Mercedes builds the Smart

Volkswagen builds Bentley and Bugatti

The following list of cars are unique in that each pair are all the same vehicle but sold under completely different nameplates that are not necessarily connected at the corporate level. Some of these are current models and some of them are from the past. Some of these pairs result from big agreements, and some of them were the result of a one time contract. This list is not complete but it’s pretty close.

Car                              What it actually is

Chrysler Crossfire        Mercedes SLK

Honda Passport           Isuzu Rodeo

Chevrolet/Geo Prizm    Toyota Corolla

Pontiac Vibe                Toyota Matrix

Saab 9-3                     Chevrolet Malibu with a turbo

Isuzu Oasis                  Honda Odyssey

Volkswagen Routan     Dodge Caravan

Acura SLX                  Isuzu Trooper

Mazda6                       Ford Fusion

Dodge Sprinter            Mercedes Transporter

Eagle Talon                 Mitsubishi Eclipse

Suzuki Equator            Nissan Frontier

Mazda2                       Ford Fiesta

Isuzu Ascender            Chevrolet Trail Blazer

Mazda Tribute             Ford Escape

Mercury Villager          Nissan Quest

Saab 9-2x                   Subaru Impreza

Chevy/Geo Tracker     Suzuki Sidekick

Geo Storm                   Isuzu Impulse

Geo Metro                  Suzuki Swift

Saab 9-7x                   Chevrolet Trail Blazer

Mitsubishi Raider         Dodge Dakota

Mazda B series            Ford Ranger

Chrysler Crossfire (top), and the Mercedes SLK (bottom) are the same vehicle.

The Worst Cars in the World

Second installment in the ongoing series

Dodge/Plymouth Neon

The Neon was seen as something fresh and new, and represented a new direction for Chrysler in the early 90’s. They were finally weeding out all of the terrible K car derivatives from the 80’s and the Neon was poised to be something to challenge the compacts from Japan that had taken over the market. This was not to be because the Neon was such a terrible car.

1995 Dodge Neon

This car really represented a step forward for Chrysler because on paper, it had all of the same things that the Japanese rivals had, but it also had some great things that the Japanese didn’t have, such as more power, and a supposed fun-to-drive factor. These were things that would draw people over from all of Chrysler’s rivals. The Neon also made domestic offerings from the same class such as the Escort and the Cavalier, look like the Pinto and the Chevette, or any of the other old bombs from the days of the AMC Gremlin.

While Neon sales were pretty good for the first few years, it didn’t take long for the auto buying public to realize that the Neon was not really much better than the old nasty K cars that it was replacing. The people who buy cars like the Japanese cars that the Neon was supposed to compete against, don’t care about a car that says “Hi” (remember the early Neon ad campaigns), and they don’t particularly care about which car has the most horsepower. They want a car that is solid to drive and requires no repairs, and very little maintenance. As it turned out the neon didn’t meet either one of these criteria, and as such the people buying cars from Honda, Toyota, and Nissan didn’t turnout.

It’s one thing to say that the Neon is bad because it seems like the check engine light is always on, but if you consider that nearly every single Neon ever sold is going to have to have the head gasket replaced at some point, it’s easy to see just how bad they are. 10 years ago during the heyday of the Neon, technicians at Chrysler, Dodge, and Plymouth dealers could literally spend all day replacing head gaskets, and boy did those people make a ton of money doing so! This is a major repair, and something that cannot be ignored. Most of the time the head gasket would leak more oil than the Exxon Valdez. If Dodge had come up with a good way to repair them and have the repair last then you might let this one mistake slide, but it was very common for a Neon to have to have the head gasket replaced more than once for this same problem.

1999 Dodge Neon

Speaking of ignoring repairs, Neon owners get used to the Check Engine light coming on and shutting off randomly, so much so that they actually convince themselves that this just normal and it doesn’t mean anything, nor is there anything that can be done about it. They are correct in a way, for a Neon, it is normal because there is always something broken or in the process of breaking. The check engine light is just an indicator that if it’s not one thing falling apart, it’s another.

Of course this is not all, the transmissions in the Neons also have a tendency to slip or to jerk or to do anything other than shift smoothly. The lucky neon owners are the few that have a Neon with a stick instead of an automatic. These junky little gear boxes are the biggest part of the car that didn’t change much from the dark days of the K cars. The Neons were not alone in this as many of the Chrysler and Dodge models from around that time period suffered from bad transmissions as well. I would say that 80% of people who have owned a Chrysler or Dodge minivan from the 80’s or 90’s, have probably had to put a transmission (or two) in the thing at some point.

Then there is the interior. They were so cheap and junky that none of the parts fit together or stayed together. The cars all came equipped with a stereo which was needed so you could turn up the music and drown out all of the squeaks and rattles. Because the Neon is an entry level car people think that this poor quality in the interior is okay or normal. Just because a car is inexpensive doesn’t mean that it’s okay for it to fall apart. Young people who are hard on their cars often end up driving these things and their lack of proper care for the vehicle only makes the interior that much worse.

2005 Neon. The final look

The Neon was first released in 1994. Do you ever see any of these old Neons on the road anymore? Not really, probably because they have all died. This is always a good test for giving you a general idea about whether a car is good or not. The original Neons sold very well but they are a rare sight on today’s roads. Like so many other cars from the struggling big three, the Neon was a hit and great step in the right direction, but as soon as sales begin to slump, the company just abandons the model altogether rather than continue to develop it in a manner that would hold interest and maintain sales. I could name 50 cars that have suffered the same fate. They might make a few token changes to the exterior but it requires more than this to regain the interest of the buying public. The neon had two minor updates before it was discontinued in 2005, and honestly many of the early problems were remedied in some form or another. These efforts were all a day late and a dollar short. The Neon will forever be remembered as a terrible car, and those who say otherwise usually just don’t understand.

Put a turbo on it and call it an SRT-4 but it's still just a Neon.

 Other posts about The Worst Cars in the World

http://autorules.blogspot.com/2011/06/worst-cars-in-world.html

What Does Octane Mean?

87, 89, 91. If you live in the Rocky Mountain region then you will see 85, 87, and 91. These are your choices when you pull up to the gas pump. These are the various octane ratings of the fuel that the gas station is selling, and as far as most people are concerned the only difference between any of them is typically $.10 per gallon. The truth is there are more important differences besides the price but it has nothing to do with the quality of the fuel, or the amount of power the fuel will produce.

Choices, choices, choices

The octane rating refers to ability of the fuel to resist combustion until the spark is introduced into the combustion chamber. You might also say that it is somewhat of a reflection of how much octane is blended with how much heptane to produce the fuel. In order to understand the difference between octane and heptane we should have a brief look at hydrocarbon chains. A hydrocarbon is a molecule that is made up of hydrogen and carbon.

The first of all the hydrocarbon chains, or molecules, is CH4, otherwise known as methane. This is the fuel that is used to heat houses and other buildings along with running your gas stove. Methane is made from a single carbon atom surrounded by 4 hydrogen atoms. After methane comes ethane, C2H6, then propane, C3H8, then butane, C4H10, then pentane, hexane, heptane, and octane.

Octane molecule

With each successive hydrocarbon an extra carbon is added along with two more hydrogens. The small hydrocarbons are in a gaseous form at room temperature and at a normal atmospheric pressure. Starting with pentane they become liquid at room temperature but they are very volatile and vaporize quickly. As the molecules get bigger they are still liquid but they loose their volatility and do not evaporate. For example, diesel fuel is usually made up of hydrocarbon chains somewhere in the neighborhood of C14H36. If you spill a bit of gasoline it evaporates quickly, but if you spill a bit of diesel fuel it will sit there until you wipe it up. C48H98 and other similar molecules that are very long are actually polymer chains more commonly known as plastic. This obviously, will not evaporate either.

So getting back to heptane, and octane, and the numbers on the gas pump. Heptane is cheaper than octane, but octane is better at resisting detonation. Detonation, also known as knocking or pinging, and related to pre-ignition, is a condition where the air/fuel mixture burns before the spark is introduced. This happens when something causes an excessive build up of heat in the combustion chamber and that heat lights off the fuel before the spark gets there. When this happens, the piston is not in the proper position to turn the force of the rapidly expanding air, into movement of the crankshaft. Imagine a piston moving upward in the cylinder with great force and then being pushed back against itself violently by this sudden explosion. This leads to severe engine damage if it happens too much. With normal combustion, the piston is on its way down when the fuel burns, it must not be still moving up.

The greater the percentage of octane in the fuel the more it resists detonation. The number 91 on the gas pump means that the fuel from that pump has the same ability to resist detonation as a fuel blend made up of 91% octane and 9% heptane. The blend may not actually be 91% octane but the fuel behaves as if it were. Many things can be added to the fuel to increase the octane rating.

Back in the old days they used to put something in the fuel known as tetra ethyl lead (TEL) to increase the octane rating. This was back in the day when you had Regular, Unleaded, and Premium as your choices at the pump. The one called Regular is the one with the lead. Eventually we decided that it’s not a good idea to pump lead into the air so TEL was no longer used. After that we tried another compound called methyl tertiary butyl ether (MTBE) but this became controversial because it was found to be poisoning ground water.

The most common thing added to fuel today to increase the octane rating is ethanol. Fuel can be blended with up to 10% ethanol by law. Anymore ethanol than that and there is a risk of damaging fuel system components because ethanol is very corrosive. Many people oppose ethanol in the gasoline but at only 10% there are more benefits than detriments. Besides being an inexpensive octane booster, ethanol, being an alcohol molecule, has an oxygen atom in the mix. This makes ethanol an oxygenate, which provides extra oxygen at the point of combustion which in turn helps the air/fuel mixture to burn more cleanly.

Looking at the label on the pump that shows the octane rating this formula is always visible, (R+M)/2. Those with any level of mathleticism will easily see that this is a formula for a simple average of two numbers. R stands for RON, or research octane number, and M stands for MON, or motor octane number. These numbers are the results of the fuel being tested in two different ways. The research octane number is derived from calculations performed, based the blend of the fuel and how it should perform in theory. The motor octane number is derived from actually testing the fuel by using it to power a test engine. Ignition timing on the test engine is advanced until the engine begins the show detonation. The amount of advance that was applied will correspond with an octane rating that becomes the MON. The RON and MON get averaged out and you end up with the number on the pump.

The octane rating of the fuel is all about the ability of the fuel to resist combustion until the spark is introduced into the cylinder and nothing more. This number has nothing to do with the quality of the fuel. Nothing to do with the amount of power the fuel produces. Nothing to do with how clean the fuel is. Nothing to do with the amount of detergents in the fuel. Nothing to do with helping your engine or fuel system components last longer. In a round about way you might say that it could affect some of these things, but not directly, and not in most cars.

Cars that call for higher octane fuel are usually performance cars of some kind or another. These high output engines are built differently and tuned differently so they require fuel that will resist detonation. Things such as a higher compression ratio make for higher combustion chamber temperatures pre-spark. This higher temperature will light off a lower octane fuel. These engines also like to run with more timing advance which can cause the air/fuel mixture to burn too quickly leading to detonation.

If a lower octane fuel is used in an engine that requires a higher octane rating the least that will occur is less power output and lower efficiency (this is not because there is less power in lower octane fuel but because the engine will not run properly), and the worst that will occur is major engine damage. All new vehicles have the ability to limit detonation but only up to a point and only under some circumstances.

High octane fuel used in a car that doesn’t require it is simply a waste of money. No benefit can come from using a high octane fuel when it isn’t needed. Many people think it’s good because it costs more but this just isn’t true. Obviously high octane fuel doesn’t hurt the engine; it just hurts your wallet. The other condition that makes high octane fuel a waste is high elevation. At high elevation, anything over 4,000 ft. or so, atmospheric pressure is much lower than it is at sea level, and therefore oxygen density is also lower. Since atmospheric pressure is responsible for pushing air into a running engine, there will not be as much oxygen pushed in when the atmospheric pressure is lower such as it is at high elevations. This lower oxygen level, and lower pressure, in the combustion chamber automatically reduces the chance for detonation. This is why the lowest octane rating at stations in the mountain west, cities such as Denver or Salt Lake City, is 85 instead of 87 like it is at sea level.

If you live at sea level, go with the octane rating listed in your owner’s manual. If you live at a high elevation go with something lower. If you are not sure if it’s affecting the way your engine runs, try tracking you fuel economy, because any inefficiency in the way the engine runs will be manifested in the form of lower fuel economy. Don’t just put high octane fuel in your vehicle because it feels good to spend more. People could accuse you of working for the government.

The Rubber that Meets the Road

Saying that tires come in all shapes and sizes, isn’t exactly right. They do come in all sorts of sizes but the shapes are pretty much the same, round with a hole in the middle. They are all black and they all use air pressure to keep them working properly, although with all of the strange things that automotive designers have done over the years to change the style of the cars and trucks we drive, it’s kind of funny that they haven’t had cars with blue tires or red tires. The only thing they have ever tried is varying thicknesses of a white stripe around the sidewall.

Tires are an extremely important part of the car and yet they are always neglected or forgotten. Without decent tires a car turns into an instrument of death and chaos. That may sound silly but it’s pretty much true. The tires keep the car in control and sticking to the road at all times. When it’s going straight, and when it’s turning, when it’s on smooth clear pavement, and when it’s on rough, bumpy or slippery surfaces. The tires also contribute substantially to the ride quality. When considering that the tires are bouncy air cushions that the entire weight of the vehicle is resting on, it’s easy to see that a tire problem is going to affect the way the ride feels and the way the vehicle handles.

A very interesting tread pattern. Each row of tread is different
and grips differently from the rest.

Tires are meant to provide a way for the vehicle to stick to the road. The rubber compound that makes up the tire is what does the sticking. The depth of the tread doesn’t have much to do with causing the tire to grip. The tread on the tire is only there to move water and snow out from under the tire so that the rubber can meet the road. Some tread patterns are not meant for use in snow and ice and some are designed specifically for that purpose. If you drive your car in all types of whether then all-weather tires are what you want. They will give you adequate performance in all conditions, but they will not give you the best performance in any conditions.

Tire Sizes

The most confusing thing about tires is perhaps the way that tire sizes work. If you have ever looked at the sidewall of the tire you might have seen something such as P215/65R15 89H. Most of this seems like nonsense but numbers of course, mean things. Starting with the letter at the beginning, this is usually a P or an LT. P stands for “passenger” meaning the tire is intended for passenger cars. The LT stands for “light truck” and is intended for; you guessed it, light trucks. This is any truck or truck like SUV even if it’s a full size truck it is still only a light truck.

The number 215 is a direct measurement of the width of the tire in millimeters. This is pretty easy to understand but the next number 65, is the aspect ratio. This ratio is the measurement of the height of the sidewall of the tire expressed as a percentage of the width. So in this case the side wall height is 65% of the width of the tire.

The next letter R refers to the type of construction. In this case R stands for “Radial” meaning that it is a radial tire. A radial tire is a tire that has the steel cords inside laid out in a radial pattern. All common tires today are radial tires so it is really pretty rare to see something other than an R in this spot. Old tires might have a B for bias belted, or a D for diagonal bias.

The number after this letter refers to the diameter of the rim in inches. Why they size part of the tire in millimeters and part of the tire in inches makes no sense but that’s the way it is. Many old tire sizes were all in inches and some off-road tires can still be purchased this way. Something like 31X10.5 R15 would be an example of a tire size in inches. The total diameter of the tire is 31 inches, and the width is 10.5 inches, made to fit on a 15 inch rim.

The next number, in this case 89, refers to the load rating of the tire, or how much weight the tire can safely carry on a regular basis. The number is kind of an arbitrary value, the higher the number the more load the tire can carry.  These standards are set by the Department of Transportation and will normally range from 70 to 110.

The last letter which is an H on this tire, refers to the speed rating of the tire. A tire with a speed rating of H can safely be driven at speeds up to 130 mph without centrifugal force ripping the tire apart. The highest speed rating is Y which means the tire is safe up to 186 mph. Many people think that Z is the highest rating but the letter ratings skip around a bit. On very high speed tires a Z is added before the R so the tire will be called Z rated but this is not the case. The Z in this position indicates it is a tire that is intended for use over 149 mph but the actual speed rating is still at the end of the tire size number. A good example of this is 285/35ZR19 99Y. This is a Y rated tire not really a Z rated tire. Exceeding a tire’s speed rating is very dangerous and can lead to a high-speed blowout which may lead to a loss of control of the vehicle. Some light truck tires might have a P or Q rating which is somewhere between 90 and 100 mph. The vehicle these tires are mounted on may easily go faster than this. Driving a vehicle with one of these tires faster 90 to 100 mph would not be a good idea.

One more marking worth a mention, all-weather tires will either say all-weather or all-season on the side, or they will be marked with M+S which stands for mud and snow. Unless you live in a place like Phoenix, Arizona or your vehicle is only used under certain weather conditions, all-weather tires are probably the best option.

Tire Maintenance

Of all of the important systems on a car that require maintenance, tires are probably the easiest and the cheapest to maintain. All that really needs to be done is regular pressure checks and an occasional tire rotation. Despite the fact that this stuff is cheap and easy, most people do not have these things routinely performed on the cars that they drive. That’s their choice but remember the instrument of death and chaos? That is what results from a lack of maintenance.

Every vehicle on the road should have a tire pressure gauge in the glove box so that tire pressure can be checked a couple of times a month. Most gas stations have an air hose that can be used to inflate the tires if needed, and probably 25% of those air hoses are actually in proper working order so you should be able to find a place where you can check your own tire pressure, and top them off if needed. Checking tire pressure with a run of the mill tire pressure gauge requires no skill, and neither does filling the tire with air. Most automotive technicians will gladly charge you to check your tire air pressure for you, and maybe they will even do it for free, but guaranteed they will mock your laziness or ineptitude behind your back because you cannot check them yourself.

Wear indicator between the tread blocks touching the
pavement. This means that the tires are worn out.

In order to find out what your tire pressure should be you can look in the owner’s manual, but if this is lost, or just too confusing, the other place that you can look is on the tire information label. This label is usually posted somewhere on the inside edge of the driver’s door or driver’s door frame. If the label is not there it could also be on the inside of the glove box on under the lid of the center console. Do not look on the side of the tire. This will only tell you the maximum pressure that the tire can stand before it becomes dangerous once it gets hot.

Tire rotation is something that you could easily do yourself with a few simple tools but since the car must be lifted you may just want to have this done by a professional. Tires should usually be rotated about twice a year. This usually works out to be about every 6,000 to 7,000 miles. Some special off-road tires or snow tires with very soft tread may need to be rotated more often.

The reason tire rotation is important is that it allows the tires to wear more evenly. The front tires on a vehicle with front wheel drive will wear out the front tires much faster than the rear tires because the front tire both steer and propel the vehicle. Vehicles with rear wheel drive usually wear the rear tires a bit faster than the front. If the wheel alignment of the vehicle is not perfect the tires will wear even more unevenly. Sometimes the tires on a particular vehicle just won’t wear well even if the alignment is good. Proper rotation will always make the tires last longer.

Tire Problems

Uneven wear is the most common tire problem. When the tread doesn’t wear the same across the entire tread surface on the same tire, it is called uneven wear. Things that usually cause this are wheel alignment problems or tire inflation problems. Wheel alignment problems can be caused by a lack of proper adjustment, or worn out or damaged parts. This must be diagnosed by someone who knows what they are doing. If the tires are worn more heavily on one edge of the tire compared to the opposite edge then there is an alignment problem. If the wear in the tire appears wavy or if individual tread blocks seem to be wearing on an angle then this is probably an alignment problem.

This tire has good tread over most of the surface, but the
right side is so work out the steel cords are poking through.
This is a major alignment problem.

Tire inflation problems that cause uneven wear can be easily diagnosed by anyone. If the center of the tread around the circumference of the tire is worn more than the outside edges of the tread then the tires have likely been run while overinflated. This is common because many people don’t use a pressure gauge when they put air in their tires. They put air in and just look at the bulge in the sidewall where it sits on the ground to come up with a guess as to when to stop pumping the tire full of air.

If you see the opposite condition, wear on the outside edges but not down the center, then the tire has been underinflated. This is common because it means that the tire pressure is never checked and the car is driven without enough air in the tires. If either one of these inflation conditions is caught before the difference in wear is extreme then the pressure can be corrected and monitored and the tires will usually even themselves out.



The tire on the left is underinflated. The tire in the middle is overinflated.
The tire on the right is normal.

 Other problems or forms of tire wear are an indication of a defect in the tire, or the inner carcass of the tire coming apart. If the tread of the tire seems to be worn around just a portion of the circumference, but the rest of the tread along that same line around the tire looks better, then the tire is experiencing tread separation. This means that the tread layer of the tire is detaching itself from the carcass. Another condition that may be noticed with tread separation is a vibration that begins around 30 to 35 mph but then disappears around 50 mph. Sometimes this is mistaken for an imbalance but it is not. An imbalance in the tire and wheel assembly will cause a vibration that will usually begin at a higher speed but will only get worse as speed increases, and will never just vanish. Tread separation is very dangerous and the tire must be replaced to correct this condition.

Major tread seperation. Notice the big deep crack on the right side.
This is a very damgerous tire, not to mention that the ride quailty of this
vehicle was terrible.

A true tire blowout of the worst kind.

A bulge in the sidewall is also a dangerous yet common condition. This means that the steel cords in the sidewall have broken allowing the air pressure in the tire to cause the bulge in the rubber. This is a weak spot that will be prone to complete failure at some point, but will most likely fail at high speed when the tires are their hottest and the pressure is the highest. Many times the broken cords are the result of the vehicle taking a curb shot. If the car is driven into the curb or slides into the curb in the winter, the sidewall gets pinched and it can break the steel cords. A tire with a bulge in the sidewall must also be replaced and cannot be repaired.

A Doughnut You Can’t Eat

If the tires are very neglected, the spare tire is even more so. The main thing to remember with the spare tire is to check the pressure once in awhile. Many times people find a flat tire on their vehicle and go to put the spare on only to find that it too is flat or at least very low. The other thing is that spare tires are usually meant for temporary use and should not be used for extended periods.

If you are lucky, the spare tire on your vehicle is a regular full size tire and not one of the temporary doughnut spares. These compact spares are now the standard on most cars because they are cheap, they are light, and they are easy to stow. Anything that manufacturers can do to make a car cheaper, lighter, or easier to package, will be done, even if it comes as a compromise. The problem with these little spares is that they are not meant for speeds much above 55 mph. They are only meant to get you to a tire shop in the next town. The problem is that this is not very convenient because stopping at a tire shop in the next town isn’t always convenient.

Some four-wheel-drive vehicles and SUV’s will have a doughnut that is full-size. These don’t have quite the same restrictions as the small ones but they are not the same thing as having a regular full-size tire for your spare. If you do have a regular tire and if the rim matches the rest of the rims on the vehicle, you can rotate your spare through the regular rotation. This will allow you to actually use that tire and it will make all of the tires last a bit longer.

You Get What You Pay For

When buying new tires it goes without saying that you should buy tires that are the same size as the ones that the vehicle came with. Changing the size of the tire will change the way the vehicle rides, handles, and it will also cause your speedometer and odometer to read inaccurately. Sometimes some custom rims can add a nice look to your ride and this is okay to do as long as the overall diameter of the tire remains the same. So if you vehicle came with 16 inch rims and you want to put 18 inch rims on it,  change the tire to something with a smaller aspect ratio. The new aspect ratio must be 1 inch shorter which will add two inches to the inside opening of the tire.

The other thing to remember when buying tires is that you get what you pay for. Don’t buy cheap tires, it’s not worth it. This doesn’t mean that the most expensive tires are the best tires; it just means that you should always try to spend a little extra. The problem with the cheap tires is not just that they tread wears out quickly, but they usually suffer from other problems before the tread wears out. Things like vibration problems, tread separation, conicity issues (a condition that can cause the vehicle to exhibit problem with wheel alignment when really there are none), and other things render the tires useless while there is still tread left.

Stay Connected

To the road that is. There are a few systems on your vehicle where you never want to see failure while driving, and the tires are one of them.  If your engines blows up while driving down the road, no big deal. If your transmission falls out on the freeway, it doesn’t matter. If one of your tires gives up at 80 mph, or if you have no tread left and you hit a big puddle at high speed, then watch out because you may not be able to keep it under control. Take care of your tires; remember that your life is riding on it.