Is it cheaper to drive, or to fly?

I was recently looking for airplane tickets from San Jose, California to Seattle, Washington. The cheapest tickets available for the dates I wanted were $310 for a round trip. The natural question to be asked here is if it’s cheaper to drive, or to fly? If you are planning a trip, you should follow these steps if you’re looking to save the most amount of money.

1) Find out how expensive the plane tickets are going to be

Be sure to check out a couple sites such as expedia.com, Travelocity, or AAA if you are a member. Don’t just look at the presented price; be sure to include tax and booking fees if applicable.

2) Find out how many miles the journey will be

I recommend using Google Earth to find directions from one place to another. This program may be a little slow if you don’t have a good graphics card from nVidia or AMD, so you could try yahoo maps or MapQuest if you don’t have a graphics card for your computer.

3) Find out how long the journey will take to drive

Google Earth and other websites will tell you an estimated time to arrival. These programs take the route that it calculated, looks up the speed limit and the distance for each segment of the road, and use that information to compute the estimated time to arrive. If you drive over the speed limit, you will get to your destination faster, but you will also use more gas. Typically, if you go faster than 65 miles per hour you will consume more gas for the same miles traveled.

4) Find out how many miles per your car gets

You can easily look up the EPA rated MPG for your specific car online. Be sure to record the miles per hour on the highway. Please note that these numbers are only an estimate. My car is rated at 36 MPG highway, but actually gets 43 MPG when using cruise control at 65 MPH. If you have an electronic meter to tell you your miles per gallon, that’s even better.

5) Calculate how much it will cost you to fill up your car

Gas prices vary per region, but the national average will give you a good estimate. Be sure to calculate for both the trip to and from your destination.

6) Reality check

For long journeys, you can be in the car for over ten hours in a single day. You need to do a reality check. Now that you know how much money it’s going to cost you to drive to and from your destination and you know how much tickets cost, you need to calculate how much money you will save by driving. Is this number worth it to you? For my San Jose to Seattle situation, driving for a day each way will cost me over 200 dollars less than flying. Since it’s going to be a long Christmas break, it is worth it to drive instead of fly. But you need to do a reality check and make sure it makes sense for your specific situation.

Other considerations

Depreciation of your car

The more miles a car has, the less it is worth. If you plan on selling your car, you may want to take depreciation into account. If you are renting or leasing a car, make sure that they aren’t going to charge you for the extra miles you’re going to put on the car.

Safety

Driving in a car for 12 straight hours isn’t the safest thing to do. Some people have trouble concentrating for that long, which can lead to an accident. Flying in an airplane is statistically very safe. Flying is actually safer than driving a car for a long distance.

Boredom

On one hand, driving can save you money, but it can also be extremely boring. When you pay extra for an airline ticket, you can arrive at your destination much, much faster. You are paying for that convenience.

Rental car

Rental cars can be extremely expensive, especially if you are under 24. If you plan on flying to a location and using a rental car for a couple days, definitely take that into account. Of course, if you drive your own car, you won’t need to rent one.

Hotel expense

If a trip is simply too long and you need to spend the night in a hotel, you need to take that into account. Generally, if you have to spend a night in a hotel on the way to, and on the way from your destination, it’s probably easier and cheaper just to fly.

Posted under Saving Gas, Saving Money

This post was written by admin on November 18, 2008

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Nissan CVT Transmission reviewed in detail

There are plenty of websites which say what the CVT transmission is, but very few websites give a detailed review of Nissan’s implementation of CVT in their vehicles. Nissan uses CVT in several vehicle models, but this review will focus around the Nissan Sentra SL 2.0, 2008. A few months ago, I moved and had no choice but to purchase a car. I decided to get the Nissan Sentra because of its introductory price and high fuel economy. Before I get into the review, allow me to explain just what normal and CVT transmissions are.

Normal transmissions have a specific number of gears, anywhere from 4 to 6 gears, usually. While this is the most widely used type of transmission, there are several problems with it. One major problem is that car engines run most efficiently at specific RPM and torque curves. Normal transmissions are designed with gear ratios to match for optimality as close as possible, but the engine is rarely running with an optimal gear ratio in your normal day to day driving scenarios. Normal transmissions also have one more notable disadvantage. When switching from one gear to another, the car looses torque momentarily. Switching gears is one of the most noticeable and undesirable features of normal vehicle transmissions.

CVT = Continuously Variable Transmission

CVT transmissions are different. As the abbreviation may indicate, a CVT transmission has a nearly infinite number of gear ratios. The transmission can switch between these gear ratios seamlessly. In theory, this should completely eliminate the problem of shifting gears. Shifting gears is an unpleasant feeling and wastes a surprising amount of gas. Therefore, in theory, the CVT should be able to save you some gas money. The other major advantage to CVT transmissions is that they can keep the effective gear ratio optimal for the engine’s current RPM and desired torque. This is another major feature which can save you some serious gas money. Often, you will find yourself driving, and you’ll notice that sometimes you push the gas pedal down to get more torque and the engine stays at the same RPM! This is because the CVT transmission is simply changing the effective gear ratio in order to have the most fuel efficient operation.

Nissan Sentra’s implementation of the CVT transmission

Now for the actual review! First, we can take care of the positives. One feature that is cool about the Nissan Sentra is when the car is idling. All cars have an idle speed set so that the car slowly moves forward when you release the brake pedal. This idle speed is the same whether or not you are creeping through a parking lot, or stopped at a stopping light. Nissan Sentra’s transmission takes a completely different, gas saving approach. When you stop the vehicle for more than a second, the CVT adjusts itself to allow the car to use less gas when idling. This means that whenever you are stopped at a stop light, your car will use much less gas when idling, which will save you quite a bit of money. When you release the brake pedal, the CVT adjusts to give the engine enough torque to slowly move the car forward just like a normal car.

The other great thing about Nissan’s CVT is that it really does keep your engine at the optimum gear ratio while you’re driving steadily. This is perhaps the biggest fuel saver of all, especially when you’re constantly in motion, and not in stop and go traffic.

Disadvantages of Nissan’s CVT

Even though CVTs have been used for years, Nissan still manages to really screw it up. First things first, let me explain a little bit about who I am. I’m an electrical engineer, and I’ve taken many classes pertaining to embedded systems and signals and systems. The gear ratios for the CVT are controlled purely through software which runs on an embedded processor in the car. Unfortunately for Nissan, they put in a great transmission, but the embedded software is seriously lacking. The Nissan Sentra could’ve been a great vehicle if they had just spent more time writing decent control software for the transmission. The following problems are caused completely or almost completely by software problems in the Nissan Sentra.

Problem 1 - The CVT simulates geared transmissions

The software controlling the CVT transmission is designed to simulate a geared transmission. That’s right, you read that part correctly. The biggest advantage of the CVT is that it can theoretically keep the engine at the most fuel efficient gear ratio. Well, Nissan throws that idea out the window when you’re starting the car from a complete stop. Suppose you are at a stop light, and you are at a complete stop. The light turns green and you accelerate to 45 miles an hour. During this acceleration, the engine will actually rev up, then simulate a gear change and rev back down. This wastes gas, and it wastes your money. Although this transition between two imaginary gears is much smoother than normal transmissions, you still lose torque and fuel economy. The only reason this happens is because some project manager at Nissan decided drivers would be more comfortable with a familiar gear transition while accelerating. The saddest part of this problem is that it’s all because the software is poorly implemented. Why would someone buy a CVT transmission just so it can simulate a normal transmission?

Problem 2 - The CVT intentionally slows your car down when coasting

Another serious problem is how engine braking is handled. Usually, when you are driving and release the gas pedal, your car will slow down. This is partly due to tire friction, wind resistance, and the engine is also slowing down the car through the transmission. Unfortunately, our friends at Nissan decided to make the CVT simulate the engine braking of normal transmissions. Of course, this is implemented in software only. What does this mean for you? It means that when you release the gas pedal and start to coast, the CVT actually slows down the car quite fast. Obviously, if you coast a lot in order to save gas, you can expect this ‘feature’ to waste a lot of money. The best way to get around this is by pressing the gas pedal extremely gently. Very little gas will go to the engine, and the CVT will no longer engage in engine braking. Honestly, I’m not sure what Nissan’s engineers were thinking when they decided to implement this. I have come across a forum where a person had successfully reprogrammed his CVT transmission to disable engine braking completely. But unless you’re a skilled mechanic with very expensive tools, you are not likely to be successful in disabling the CVT engine braking.

Problem 3 - The CVT can’t change effective gear ratios fast enough

If you’re following someone too closely, you may have to engage the gas pedal, then the brake pedal, and then the gas pedal again. Unfortunately, there is a physical limitation to how fast Nissan’s CVT can change effective gear ratios. In the scenario described above, you can expect your CVT to jerk the car severely. This is actually a physical problem with the CVT design, not the software. The best way to avoid this is by changing your driving habits. If you apply the gas pedal, then the brake, when you release the brake, give yourself about one and a half seconds of time until you step on the gas pedal again. This will avoid the jerk.

Problem 4 - Constant droning noise

Noise is something none of us like to hear when driving our cars. Now, I’ve read many sites that overstate the noise the transmission makes. Yes, it is audible when you are accelerating, but I’m rarely bothered by it. Some people online seem to find the noise annoying, so be sure to pay attention during your test drive to see whether or not you are bothered by a low, constant droning sound.

Conclusion

Well, there you have it. Hopefully, this article has given you some insight as to what the Nissan Sentra’s CVT transmission is like, and some serious downfalls to the transmission. Overall, it’s possible to get very good fuel economy partly due to the transmission design. For example, when I’m going 55 miles per hour on a highway with cruise control on, I can expect to get 45 miles per gallon. When I go 60 miles per hour on the highway, I can expect to get 43 miles per gallon, which is great. Nissan’s CVT transmission is not perfect, and many of the flaws can be blamed on software, not hardware. Hopefully Nissan’s next release of the Sentra will include a better transmission with better control software.

If you enjoyed this article and would like to view more gas saving tips and articles please check out these articles, or any posts listed under the ‘saving gas’ category. Remember to check back often for updates and more articles on how to save money.

Posted under Saving Gas, Saving Money, Shopping

This post was written by admin on September 10, 2008

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Buying used gas guzzlers might make sense

If you’re thinking about buying a used car, it might be worth your time to look at some old, used gas guzzlers. That’s right, you read that correctly. It all comes down to how much you drive your car. If you drive over 20,000 miles a year, you should probably spend some time looking for fuel efficient cars. One of my favorites is the Nissan Sentra, which is not too costly, but gets great gas mileage.

If you drive less than 10,000 miles per year, it actually might make great financial sense to buy a used gas guzzler. Why is this? As it turns out, because gas prices have recently risen so quickly, people have begun trading in their old cars for more fuel efficient ones out of fear and speculation. This is great news for car buyers! Because there are so many used gas guzzlers for sale and little demand for them, prices have drastically come down. Most gas guzzlers have been devalued over 50%, which means you essentially get half a car for free. By buying used gas guzzlers, it’s fairly easy to save several thousand dollars upfront. Of course, you’ll be paying more for gas, but lets see how much this really costs you.

Suppose you buy a used car for $8,000 less than retail, and gets 20 miles per gallon. Suppose that, had you spent that money for a new fuel efficient vehicle, you could get a car that gets 30 miles per gallon. Suppose you don’t drive very much, only 10,000 miles per year. Now let’s assume an average of five dollars a gallon. If you get the fuel efficient car, you will save (10000/20) * 5 – (10000/30) * 5 = $833 dollars per year. Think about this scenario again. If you buy the more fuel efficient car, it would take 9.6 years to break even!

Now, guying used gas guzzlers doesn’t save money for everyone. If you drive 30,000 miles a year, the above scenario may be recalculated. In this case, you would save $2500 a year, which means you’ll break even in only 3.2 years if you buy the more fuel efficient car.

What I really want you to get out of this article is that you don’t drive very much; it may actually cost you a lot less money to buy a used car which gets poor gas mileage. The buyer and seller market has created an environment where you can easily get massive discounts on these cars. On the other side of the token, if you drive a lot, it’s much better to pay more and get a fuel efficient car. So remember, before you buy a car, be sure to do the math and see if it makes financial sense for your specific situation.

Posted under Saving Gas, Saving Money, Shopping

This post was written by admin on September 4, 2008

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