Help.. fuel consumption.... rpm at 120kms

[barvibe]

Hi, newbie here. Bought 2009 Vibe 1.8L auto. I'm getting between 9 and 11.5 L/100 in this thing. I have already complained to GM about it. I have brought it back to the dealer (Richmond Hill Pontiac Buick) and the serviice advisor there is unwilling to test the vehicle at highway speeds. Needless to say I won't be going back to them.Please don't tell me to break in the engine. I'm not talking about a 20% decrease in mileage I am in some instances talking about an over 60% decrease in posted consumtion.The reason I need help is this. I believe the car is running at higher than normal RPM. At 120kmph my RPM is at 3100. Anyone else out there with an 09 vibe auto that can tell me is this is what they run at? Anyone else out there having mileage issues? I'm getting extremely frustrated, I hope someone in the forum can help!!Cheers

[northvibe]

oh crap all that metric stuff idk what that is in US spec mpg but considering its winter so its crappier gas and its a new car and auto, you should range from 24-28 depending on driving style. at 120km its like 70-74mph 3100 rpm seems about right. That is a new engine , it has dual vvt (exhaust and intake) compared to the 03-08 1.8 which was "single" vvt. again its winter the gas is crappier everyones mileage drops.

[joatmon]

Here's a link to a Speed vs RPM calculator that I filled out with the tire size and gear ratios from the 2009 Vibe specs (The base auto is a four speed, the calculator insists on 5 gears, so I made 5th the same as 4th) It outputs in mph, not kph, but 120 kph is 75 mph, and the calculated speed at 3100 rpm is 74.8 mph, so I say your RPMs are exactly what should be expected at 120 kph.If there is a problem with your car causing the fuel efficiency to suck, it's something else, not an RPM vs speed issue.

[prathman]

As Joatmon said, the RPMs seem correct. Your mileage in US terms is in the range of 20.5 - 26 mpg. If that includes much city or short distance driving then it doesn't seem too bad. Fuel consumption is always significantly worse before the engine is fully warmed up and that can take a big toll on winter mpg figures. In addition there's the reformulated winter gas for easier starting at the expense of efficiency, denser air creating more resistance, longer engine idling periods, greater rolling resistance on snowy streets, etc.BTW, if the lower end of your mpg range, i.e. 20.5 mpg represents a 60% decrease of what was 'posted' then you must have been expecting over 50 mpg. That seems totally unrealistic for normal driving, especially in winter.

[Neouka]

yeah... keep in mind that in the winter your mileage drops pretty significantly.All summer I was pulling 36-39 US mpg (43 was best ever) per tank of gas. I don't go much over 105 km/h on the highway.Now that it's winter, I put a set of brand new winter tires on, using winter gas, and my car idles more to warm up a bit before I start driving. I'm getting 31-33 per tank. It sucks ;.;

[thebarber]

ya, you gotta remember, youre driving a 2800lb 4cyl in winter weather....9-11.5L/100km isnt bad (though not GREAT)gotta keep the speed down too if you want better mileage...furthermore, the EPA estimated mileage isnt something to go complaining to the dealer about...theres nothing they can do because youre not getting 7L/100km in the winter on the highway speeding 20km/h....my matrix xrs was the same way.....9.5L/100km city and 7.5L/100km highyway in teh summer, but come winter, itd drop fairly heftily. i once drove waterloo to london at about 150kph and boy did it suck the gas down!things to keep in mind: keep the speed down, make sure your tire pressure is up (i now run about 36-38psi in my tires) and watch HOW you drive.....use cruise, the gas isnt an on/off switchanyways, i hope your mileage improves...

[barvibe]

maybe my math is wrong.. posted numbers on this car are 6.3L/100km highway and 8.4L/100km city. Since I'm driving mostly highway I figure 60% higher consumption like this.6.3L/100 x .60 = 3.78L/100km , so 6.3L/100km + 3.78L/100 = 10L/100km. This is what I"m averaging. I use cruise and don't play with the accelerator. In Canada the dealers use imperial as opposed to US gallons and the posted number is 46mpg. I think even in the dead of winter at 120km per hour I should be getting at minimum 32mpg, no worse. If I were getting this number I wouldn't be looking for the solution.Cheers and any other tips or info would be appreciated!!

[DarkSpork]

Its probably about time I add air to my tires. They look low and it is colder outside, I just don't want to add too much.

[tribalman]

do you let your car warm up each and every time before you drive? that will also drive your gas consumption way down. the first winter i had my 04 i was getting 18 MPG because i was letting the car warm up. i stopped doing that and it went back up to 28. i get about 28 in the winter and around 32 in the summer. and yes, ~3.1k is the right RPM for driving at 75mph/125KPH.don't let the car warm up for so long and also slow down. it will increase your efficiency.

[whytea]

That seams high to me I have an 09 2.4l and avg about the same as you.Are you heavy on the gas and breaks?