rob-cyn

Dont you think you are wasting your money changing synthetic oil every 3000 miles.

ChevyMgr

Since I saw this on the 10:00 evening news last night, and we know everything on the evening news is correct, I thought I would add it to this thread. They stated four myths about fuel economy. It came from Consumer Reports, which I have usually found to be pretty accurate.

Click the link below to view the web page.


http://www.consumerreports.org/cro/c...-406/index.htm

MYTH BUSTERS

Morning fill-ups. A common tip is to buy gasoline in the morning, when the air is cool, rather than in the heat of the day. The theory is that the cooler gasoline will be denser, so you will get more for your money. But the temperature of the gasoline coming out of the fuel nozzle changes very little, if at all, during any 24-hour stretch. Any extra gas you get will be negligible.

Air conditioning vs. opening windows. Some people advise you not to run the air conditioner because it puts more of a load on the engine, which can decrease fuel economy. But others say that opening the windows at highway speeds can affect gas mileage even more by disrupting the vehicle's aerodynamics. Our tests show that neither makes enough of a difference to worry about. Using air conditioning while driving at 65 mph reduced the Camry's gas mileage by about 1 mpg. The effect of opening the windows at 65 mph was not even measurable.

A dirty air filter. Our tests show that driving with a dirty air filter no longer has any impact on fuel economy, as it did with older engines. That's because modern engines use computers to precisely control the air/fuel ratio, depending on the amount of air coming in through the filter. Reducing airflow causes the engine to automatically reduce the amount of fuel being used. Fuel economy didn't change, but the Camry accelerated much more slowly with a dirty filter.

One other thing to note that wasn't in the Myth Busters category was the use of Premium Fuel. I know a lot of users swear their economy is better with it, but I have always doubted that the octane of fuel was what gave them the better economy.

IMHO, to do a fuel economy comparison on your vehicle MPG with premium against regular, you would need. The exact engine conditions at the the exact operating temperatures, with the exact passenger/cargo weight, with the exact wind conditions, with the exact air temperature, with the exact barametric pressure, with the exact idling time, with the exact acceleration and deacceleration speeds, etc...ect...to get an EXACT comparison.

So that being said here is what Consumer Reports states:

Don't use premium fuel if you don't have to. If your car specifies regular fuel, don't buy premium under the mistaken belief that your engine will run better. The only difference you'll see is about 20 cents more per gallon. Most cars are designed to run just fine on regular gasoline. Even many cars for which premium is recommended will run well on regular. We have found that the differences are imperceptible during normal driving. Check your owner's manual to find out if your engine really requires premium or if you can run on other grades.

Now all that being said the SS still NEEDS TO USE PREMIUM, no matter what!

Doc brown

#2 & #4 of these "myths" are ones that I will always challenge a bit.

As far as open or closed windows, my experience is similar, in that it makes little difference. Where I find the inconsistancy is whether the A/C eats more gas. In my experience, it depends on the car as much as driving habits. I've had cars where it makes very little difference, and others where you could actually watch the needle drop. I've gotten as much as a 4mpg drop im mileage while running the A/C in some cars. The bigger the vehicle, the more susceptable they seem to be.

The term "your mileage will vary" comes to mind here. First, I whole heartedly agree, if your car's manual recommends regular, only run regular. However, I've owned several "premium optional" cars. My Cadillac Catera ran like crap on regular, and super smooth on premium. But there was no difference in mileage, or power, no matter what grade we used. So we compromised and ran mid-grade. It ran fairly smooth and didn't break the bank for no good reason. So far, it makes CR's conclusions sound right on.

Now our HHR (2.4L) is another matter. After the first month of using regular, I was averaging 24.5 per tank full. Thats doing the math on each fillup, not using the DIC. I put on about 250-300 miles per week, with mixed city/freeway conditions. I was skeptical about improved mileage using premium, especially since my Caddy gained nothing by using it. But for a couple of bucks a week extra, I thought I'd give it a shot. I've been using premium for the past 5 weeks and have been averaging 26.5 per tank full. 2 MPG better, which results in a little over $300 a year cheaper to run premium (at $4 a gal), assuming I put on 20k per years. It also runs a tad smoother at idle, and while there is no power gain at street speeds, there is noticably more power at freeway speeds. Judging from the type of driving I did this past weekend, there is less of an improvement in mileage when doing mostly city driving. So for those who drive their 2.4L HHR in mostly city conditions, there may be little reason to use premium. Keep in mind that where I live we have to use E-10. I have no idea what my results would be if I were able to use straght gas.

True, there is no good way to do an EXACT comparison. My conclusion is that one has to try it for themselves over a period of time, like a month or more of using each grade. For the most part, people will have the same pattern of driving and similar conditions over a period of time. So they should be able to compare two typical months side by side and figure out if premium is worth it or not.

stangable

I have found that I get much worse gas mileage when using the cruise. The little 2.4 struggles up the slightest inclines and is very prone to downshifting (and sometimes downshifting much harder than necessary). So on road trips I just stay away from the cruise or if I am using the cruise and I see an incline coming, I just tap the brake and take over.

It has saved me 2mpg on some trips. I'll get about 30 on the interstate at 70-73 mph without the cruise and around 28 with the cruise.

Thats the only thing about the car I really dont like. In order to pull itself around sometimes it really has to work. I would prefer a small v6 instead. Something similar to the Dodge Intrepid. You can run them around and easily get 30mpg.

The other thing I have tried was 91 octane. I ran the same 300 mile trip 4 times. Twice with 87 octane and twice with 91. I got about 1.5 -2mpg better with the 91, but the extra price for gas made it a moot point. I didn't save anything and I didn't lose anything.

nijntje

D@mn you all guys (and gals).

Your milage doesn't look that bad compared to mine !
I'm struggling between 18 L/100km which makes for a lousy 15 MPG at first and now I seem to get stuck at 13 L/100km which is around 18 MPG.

Have to say that it still is a brand new car with only 3000 ridden km's (around 1800 Miles).

Does this ever improve with age and ridden Miles ? Or am I looking at the best I will get from this car ? Other than this it's the best car I ever owned.

HipHotRod

Im getting 15 / 16 in town as I do mostly all short trips. I reset the DIC for freeway traveling and I get 29/30. Mine is brand new as well w/3300 miles on it so far. From what Ive seen from others, the MPG does seem to get better as the car gets more miles on it. Crossing fingers.

Old Lar

I found just the opposite of Doc Brown. No improvement in milage with premium vs regular gas. 2000 miles of typical driving with premium = 31 mpg. Thousands of miles using regular = 32 mpg all with a 2.4L auto. Insignificant difference to spend an extra 20 cents per gallon for premium fuel.

ChevyMgr

The slight improvement in CONTROLLED tests shows that the gain in MPG is negated by the higher price. At best you will break even and if You get stuck say in big city traffic jam, the idling will drop you below the break even point.

ChevyMgr

I think this is another waste too. There is no need to change synthetic that often. Just think how many gallons of gasoline you can buy with the money you save.

HHR4JK

chevymgr.
1)whats your opion on DIC telling when to change your oil.. regular oil that is.....
2) so how often does one change synthtic oil ?