Pontiac G6 Forum banner

1 - 20 of 58 Posts

·
Registered
Joined
·
21 Posts
Discussion Starter #1
We got a '07 G6 4D with the 2.4L a couple of weeks ago with 17K miles on it. We took it for it's first "road-trip" with the family, drove about 250 miles and the display said it got 24.5mpg. :eek: I drove it the whole way, i pretty much hit 80mph and stayed there. It's a little hilly between Atlanta and Chattanooga, but i expected it to get better milage than that. I'll run a few more test tanks with it, is there a sweet spot say at 70 or 75mph that gets the best milage? My other cars usually have one, you just have to find it. My '92 Buick Roadmaster with the 350 gets 27mpg at 80mph, but at 70mph it gets 23mpg. So i thought the G6 4 banger would be in the low 30's. Bad assumption? :eek:
Thanks for the input.
Don
 

·
Lifetime Member
Joined
·
3,269 Posts
So, was the '92 Buick Roadmaster with the 350 loaded with the family on a somewhat hilly road getting this mileage or was that the best mileage the Buick got?
 

·
Registered
Joined
·
21 Posts
Discussion Starter #3
The trip was the same road, same people (me, my wife and son) and the same amount of cargo - none. Only difference was the trips were 2 weeks apart. I drove both at 80mph steady. The Buick i calculated at the pump, the G6 i was looking at the computer reading. I intend to really check it on the next trip, like at the pump as the readout seems very low. The Buick's milage really surprises a lot of people, but it's the rear-gearing that does it on the interstate. (It's city milage really sucks at 13-14mpg) It has a 2.41 rear gear, and at 80mph the engine is only turning 1750rpm. (It idles at 900rpm so it's just off idle at 80) Contrast that with the G6, at 80 it's turing about 3000rpm. (i looked up the drive on the 2.4 G6 and it said 3.91 on yahoo)
What i usually do is fill up, make the trip and then re-fill at the same pump. I'll see next time the wife let's me take it. lol
Don
 

·
Registered
Joined
·
586 Posts
I'm not totally sure, but i think the best mileage that i have gotten was at 65mph, and it was at 34mpg. I've been having some gas issues lately (vapor loss), and my mpg has gone down to 22.6 from 25 (mixed driving).
 

·
Registered
Joined
·
33 Posts
When you looked at the MPG reading from the screen did you reset it before you left? I have the 2.4L in my 6 and when I do 80 I manage about 28 MPG. When I go 75 I get about 30 MPG and when I do 70 I get about 32-33 MPG. I have 35K miles on mine though
 

·
Lifetime Member
Joined
·
3,269 Posts
When you looked at the MPG reading from the screen did you reset it before you left? I have the 2.4L in my 6 and when I do 80 I manage about 28 MPG. When I go 75 I get about 30 MPG and when I do 70 I get about 32-33 MPG. I have 35K miles on mine though
I agree, the 3.5 we have, when reset, gets near 34mpg at 65mph. Reset the reading and calculate with the gallons vs the miles traveled.
 

·
Registered
Joined
·
16 Posts
not an 07 but I have an 05 sedan G6 gt. we took a trip from columbus Ga to buffalo NY and only used 2.5 tanks of gas. average was 34-36mpg. the car now has 36,130
 

·
Registered
Joined
·
452 Posts
I find the trip computer not very accurate even if you reset is every time. A more accurate way is to calculate it manually using distance travelled and gallons used. Most cars get the best mileage at 55-60 mph. Speed higher than 60mph air resistance usually become a major factor.
 

·
Registered
Joined
·
21 Posts
Discussion Starter #9
That's good info, i thought i had reset it but i may have just reset the trip A and not the fuel milage number. I pretty much always fill up the tank when we get fuel, so i'll actually track that next trip. Good to know the group averages at various speeds, thanks a lot guys.
Don
 

·
CrAzY Moderator
Joined
·
963 Posts
i have an '07 G6 3.5L and I get 36-38 mpg going 70 but at the same time i have cold air intake ? dont know but before i was getting bout 35-36 so it helps alittle. im happy with it now. i can drive all the way from tennesse(nashville) to west virginia(charleston) so i get pretty good just dont sink your foot in and out of the pedal keep a constant speed dont use cruise on hills and for a 2.4L 4 people in the car thats not bad at all because its a smaller engine pushing more weight thats why your buick gets better gas milage.
 

·
Registered
Joined
·
21 Posts
Discussion Starter #11
When we bought it we debatred on the 2.4L or the 3.5L and thought that the 2.4L would get better milage. The Atlanta-Chattanooga trip it was me, wife & 14 year old son with no luggage..etc. I put it on 80mph and didn't vary more than a mile an hour or so. Very smooth and i hate people who go faster/slower...etc and do it a lot (one of my pet peeves). The Buick weighs about 4800lbs, supposedly 180hp and 210tq. I would think the G6 would be a lot less weight and the hp/tq wasn't that much lower. But anyway, i'll get real numbers with gallons and it might be higher than the readout. My wife told me that i didn't reset it, so only god knows how many miles it was averaging over. lol
Thanks again.
Don
 

·
CrAzY Moderator
Joined
·
963 Posts
yup let us know bud i would like to find out the reason but one of the reasons less powerful engine the more people the more gas luggage is weight thats more gas pushing in and out on the pedal thats more gas there are so many ways to save gas also

1. Avoid prolonged warming up of engine, even on cold mornings - 30 to 45 seconds is plenty of time.

2. Be sure the automatic choke is disengaged after engine warm up... chokes often get stuck, resulting in bad gas/air mixture.

3. Don't start and stop engine needlessly. Idling your engine for one minute consumes the gas amount equivalent to when you start the engine.

4. Avoid "reving" the engine, especially just before you switch the engine off; this wastes fuel needlessly and washes oil down from the inside cylinder walls, owing to loss of oil pressure.

5. Eliminate jack-rabbit starts. Accelerate slowly when starting from dead stop. Don't push pedal down more than 1/4 of the total foot travel. This allows carburetor to function at peak efficiency.

6. Buy gasoline during coolest time of day - early morning or late evening is best. During these times gasoline is densest. Keep in mind - gas pumps measure volumes of gasoline, not densities of fuel concentration. You are charged according to "volume of measurement".

7. Choose type and brand of gasoline carefully. Certain brands provide you with greater economy because of better quality. Use the brands which "seem" most beneficial.

8. Avoid filling gas tank to top. Overfilling results in sloshing over and out of tank. Never fill gas tank past the first "click" of fuel nozzle, if nozzle is automatic.

9. Exceeding 40 mph forces your auto to overcome tremendous wind resistance.

10. Never exceed legal speed limit. Primarily they are set for your traveling safety, however better gas efficiency also occurs. Traveling at 55 mph give you up to 21% better mileage when compared to former legal speed limits of 65 mph and 70 mph.

11. Traveling at fast rates in low gears can consume up to 45% more fuel than is needed.

12. Manual shift driven cars allow you to change to highest gear as soon as possible, thereby letting you save gas if you "nurse it along". However, if you cause the engine to "bog down", premature wearing of engine parts occurs.

13. Keep windows closed when traveling at highway speeds. Open windows cause air drag, reducing your mileage by 10%.

14. Drive steadily. Slowing down or speeding up wastes fuel. Also avoid tailgating - the driver in front of you is unpredictable. Not only is it unsafe, but if affects your economy, if he slows down unexpectedly.

15.Think ahead when approaching hills. If you accelerate, do it before you reach the hill, not while you're on it.

16. Do not rest left foot on floor board pedals while driving. The slightest pressure puts "mechanical drag" on components, wearing them down prematurely. This "dragging" also demands additional fuel usage.

17. Avoid rough roads whenever possible, because dirt or gravel rob you of up to 30% of your gas mileage.

18. Use alternate roads when safer, shorter, straighter. Compare traveling distance differences - remember that corners, curves and lane jumping requires extra gas. The shortest distance between two points is always straight.

19. Stoplights are usually timed for your motoring advantage. By traveling steadily at the legal speed limit you boost your chances of having the "green light" all the way.

20. Automatic transmissions should be allowed to cool down when your car is idling at a standstill, e.g. railroad crossings, long traffic lights, etc. Place gear into neutral position. This reduces transmission strain and allows transmission to cool.

21. Park car so that you can later begin to travel in forward gear; avoid reverse gear maneuvers to save gas.

22. Regular tune-ups ensure best economy; check owner's manual for recommended maintenance intervals. Special attention should be given to maintaining clean air filters... diminished air flow increases gas waste.

23. Inspect suspension and chassis parts for occasional misalignment. Bent wheels, axles, bad shocks, broken springs, etc. create engine drag and are unsafe at high traveling speeds.

24. Remove snow tires during good weather seasons; traveling on deep tire tread really robs fuel!

25. Inflate all tires to maximum limit. Each tire should be periodically spun, balanced and checked for out-of-round. When shopping for new tires, get large diameter tires for rear wheels. Radial designs are the recognized fuel-savers; check manufacturer's specifications for maximum tire pressures.

26. Remove vinyl tops - they cause air drag. Rough surfaces disturb otherwise smooth air flow around a car's body. Bear in mind when buying new cars that a fancy sun roof helps disturb smooth air flow (and mileage).

27. Auto air conditioners can reduce fuel economy by 10% to 20%. Heater fan, power windows and seats increase engine load; the more load on your engine, the less miles per gallon.

28. Remove excess weight from trunk or inside of car - extra tires, back seats, unnecessary heavy parts. Extra weight reduces mileage, especially when driving up inclines.

29. Car pools reduce travel monotony and gas expense - all riders chip in to help you buy. Conversation helps to keep the driver alert. Pooling also reduces traffic congestion, gives the driver easier maneuverability and greater "steady speed" economy. For best results, distribute passenger weight evenly throughout car.

30. During cold weather watch for icicles frozen to car frame. Up to 100 lbs. can be quickly accumulated! Unremoved snow and ice cause tremendous wind resistance. Warm water thrown on (or hosed on) will eliminate it fast.

so as you can see there are many ways to save gas also i mean its just how you drive and everything else hope this helps?

need anything else just ask
 

·
Registered
Joined
·
21 Posts
Discussion Starter #13
LOL..
I can't tell you how many times in the past 35 years i've been driving that i've seen that list. Also 6,27 are fables and inncorrect, 20 with these modern cars is not much of a factor. I've been restoring 50's-70's cars for over 20 years as a hobby and i'm also a computer automation engineer so i'm pretty up on cars. Thanks
Don
 

·
Registered
Joined
·
21 Posts
Discussion Starter #15
A lot of people believe #6 to be true, but the effect is not what you think it may be. I've worked in the oil/gas transportation industry, on the metering computers for pipelines, tank farms, tractor-trailer loading racks for the gas that goes to the pumps. (I'm an automation engineer) With the filling stations tanks being underground, the actual temp of the gas really dosen't change more and a 2-4 degrees during the day as the underground temp dosen't change much. (most tanks are 15-20' underground) The API correction factors (all gas is corrected to 60F for measurment purposes) have a range that is really small for temp changes under 15Deg F. The factors are something like .99910, .99909, .99911, .99908, 1.0000, 1.00001.... and etc. Very tiny changes in measurments for the temp movements, the API web site has the standard correction tables if you want to have a look. What does change a lot is the amount of vapors that the gasoline emits when ytou fill the tank. The tank in your car is much hotter than the gas going into it, and the gas heats fairly quickly and emits a lot more fumes when it's going from like 70F to 90F. The EPA a few years ago created a law that by 2011 all pumps will have the "vapor collection cup system" in place to collect the air from the tank while it's being filled. You may have noticed that many pumps in the last year or so have the rubber or plastic cup that fits over the gas inlet from your tank. That's what that is supposed to do is collect the vapors.
Check out the API site for correction factors, it's pretty interesting stuff.
Don
 

·
Registered
Joined
·
452 Posts
What make a bigger difference is not the gasoline density or temperature but the gas concentration. The longer the gas sits in the underground tanks, due to water condensation, the more diluted it will become.

09 Air resistance is proportional to the square of the vehicle's speed. Double the speed and the air resistance increases four-fold. But it doesn't become significant until you reach about 50-55 mph. After that it starts to rob the engine's power at the expotential rate.

20 Automatic transmissions run cooler at neutral and in theory you can prolong the life of the tranny this way. But in practice, all that shifting back and forth between neutral and drive creates a lot of wear due to the repeated shocks of slaming the drivetrain into drive.

25 Inflating tires to their maximum pressure will decrease traction, affect ride quality and cornering ability, and increase tire wear and the chance of tire damage and blow-outs. The gain from the reduced rolling resistance is marginal. Stick with the factory's recommended tire pressure, not the pressure indicated on the tire itself.
Also, different diameter tires will confuse the ABS and Traction Control systems in addition to compromising handling and braking of the vehicle. Don't do it.
 

·
Registered
Joined
·
21 Posts
Discussion Starter #17
I agree with that except the density portion, with the tanks being 15-20' underground the temp really dosen't change much, maybe 10 degf over a day with the outside temps ranging between like 55F to 95F. The ground reacts very slowly to heating/cooling when it's several feet deep.

Anyway, my original post was to inquire about gas milage from other people's cars, not to debate what methods various people utilize to get better milage and/or various fluid properties. We strayed off topic somewhat. lol

For example, my '07 G6 with the 2.4 on a 250 mile trip got 24.5 on the display at a steady 80mph. What i was looking for was something like this:

For example my '03 Chevy Cavalier with the 2.2L Eco-Tech gets:

30mpg at 80mph
34mpg at 75mph
40mpg at 70mph
41mpg at 65mph
42mpg at 60mph
42mpg at 55mph

So the sweet spot for the '03 Cavi is around 65mph-70mph and not get ran over on the interstate. :eek:

So what i'm looking for is some data like that on the G6, with the 3.5L and 2.4L engines.


Does anyone have any data like this?

Thanks
Don
 
1 - 20 of 58 Posts
Top