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GXPJOEYP
Deep in the heart of Texas,
Go Cowboys,
Cheers,
Gary
I know during the winter months we have to run 10% ethanol and my mileage drops by 10 -15%.
I do know if I let my foot control the throttle the mileage isn't nearly as good.
My average highway speed is about 80mph, give or take a bit. Average mpg is about 21-22. Not bad for 80mph, but not what I had hoped for. I won't complain, it is still a nice ride and cheaper to feed than the old Yukon was.
Just over 13000 miles now, no troubles except for an OnStar module going out. Didn't bother me, except that it had some message every time you started the car. Got tired of the car talking to me.
Mike
I have not been to my dealer since 2007s started arriving.
Was this the sticker on a car - or "Click Here For Window Sticker" on GMBuypower or Pontiac's web site?
( These are often wrong. )
The EPA website shows the 2007 as 18 \ 27 ( 21 combined )
http://www.fueleconomy.gov/feg/findacar.htm
And on the Pontiac web site, at the beginning step of "Build Your " - it shows 17 \ 28 for the GXP.
Odd.....
- Ray
With much experience & many thoughts on MPG . . .
Details:
First – highway MPG: I have achieved over 22 MPG for a full tank only a few times in over 19,000 miles. They were close to ‘ideal’ “real-world” conditions.
‘Ideal’ “real-world” conditions - probably sounds like an oxymoron, but what I mean is: In the “real-world”, I am NOT constrained by the EPA test limits on rate of acceleration when I merge or pass or leave a traffic light. In the real world, roads have at least some traffic and I am constrained largely [ on Interstates ] by local speed enforcement rather than EPA test max speed (still 60 MPH!!) and I am free to drive with my A/C on. ‘Ideal’ conditions mean relatively light traffic, cool enough ambient temps to be comfortable without the A/C compressor running, cool enough that the air entering the motor is relatively dense, and mostly running on roads with little significant elevation change. And only me in the car, and no more than a weekend case.
My overall fuel mileage likely now stands at close to 19.0. But if I remove a few of the ‘best’ tanks ( not typical ) from the equation, the average probably drops closer to 18.5.
Second, I am satisfied with the overall fuel mileage, given the available performance & how often I utilize it. (Many smiles per gallon, thank you.)
My “around town” MPG reflects the fact that I really enjoy the V8’s acceleration – feel & sound. And I use it whenever I (safely) can. And I use all of it. WOT. Often. Thus I do not achieve the EPA estimate there. No big surprise.
[ The GXP’s acceleration is really the one dynamic performance aspect where I feel like I can legally and safely utilize 100% of the available performance = HP & TQ on public roads. Perhaps not for long at any given time, as more than 10 or 15 seconds of WOT, in second gear, will have this car moving faster than any open road speed limit in the US. But compared to lateral acceleration & braking, it is a thrill that I can regularly enjoy, asking it to deliver absolutely all the power that it has to give. In cornering, for example, I always try to leave significant margin for the unexpected & unpredictable – sand or oil or water across an apex, or another driver doing something ill advised. Acceleration is something that I can enjoy - every time I drive my GXP! ]
Although I have seen (and quoted here) that GM states DoD can function at up to 80 MPH under absolutely ideal conditions, my feeling is that in the real world, the slightest headwind, acceleration to pass, or uphill incline, etc. will result in DoD = off.
And the point in the fuel mileage vs MPH curve where above a certain MPH, under certain specific conditions, DoD will not engage - likely results in a sharp drop in MPG. In fact, I’d predict that it will result in a discontinuity (??) in the curve. Meaning a straight drop, where DoD disengages, then a continuation of the downward sloping curve – at a substantially lower MPG level as speed continues to rise.
For example. One might expect a somewhat linear drop in MPG as speed rises across the range of typical US highway travel. (Yes, I know, not really linear and not over all speed ranges, etc)
But for purposes of illustration here - If I assume that at an absolutely steady speed of 60 MPH, my GXP can achieve 30 MPG, then at 65 it might be capable of 28 and at 70 it might be 26 and at 75 it might be 24 and at 80 it might be 22 and at 85 MPH, 20 MPG.
If DoD is operable up to 70, but will not engage starting at say 73.14159 MPH for instance, the numbers might then look like this:
MPH\MPG
60 – 30 (DoD on)
65 – 28 (DoD on)
70 – 26 (DoD on)
75 – 20 (No DoD - instead of 24)
80 – 18 (No DoD - instead of 22)
I am making these numbers up, but I believe they are in the range of possibility \ reality for my GXP.
This would mean that exceeding the DoD engagement threshold would cost something like an additional 20 or more percent (24 with DoD vs. 20 at 75 MPH without DoD and 22 vs. 18 at 80, etc.) beyond the expected decrease as speed rises beyond whatever that critical speed actually is. My driving suggests that the threshold speed ( above this, DoD does not engage in ** my ** typical driving ) is between 70 and 75.
But that’s just me speculating.
YMMV.
- Ray
Still enjoying the drive – and not obsessing about MPG . . (?)
1.Rebuilt SuperCharger
2.ACDelco SparkPlugs
3.Wire Set (spark plug)
4.oil change every 3K (oil filter too)
5.New PCV Valve
6.New O2 sensor (before catylic)
7.New Fuel Filter
8.K&N filter and intake
Anyone out that can really help. with any Idea Please EMAIL ME at Sol9586@yahoo.com as you can see there has been alot of money invested and im not seeing any progress. 12.2mpg city / and 12.5mpg hwy. HELP!!! HELP!!! HELP!!!
and I am getting 25 to 28 a GAL.
Gearr