Last post on Nov 30, 2010 at 8:21 AM
You are in the Pontiac G8
What is this discussion about?
Pontiac Grand Prix, Pontiac G8, Future Vehicle, Sedan
Oct 10, 2007 (7:40 am)
Apparently not 'official' EPA #s, but I am told that the G8's Launch Site shows MPG:
"The Pontiac G8 with the 3.6L V6 engine is estimated to achieve 17 miles per gallon in the city and 24 miles per gallon on the highway. The G8 GT with the 6.0L engine will achieve an estimated 15 miles per gallon in the city and 23 miles per gallon on the highway.*
*MPG based on the EPA's new 2008 fuel economy standards "
#288 of 1278 Why can't Ford figure this out???
Oct 10, 2007 (11:43 am)
I'm really glad to see the G8 coming. I like its' looks, and the design seems good. I sincerely hope GM doesn't neuter it and offer it as an automatic only! But GM is getting smart and using its' global resources (Holden, Opal, etc.) to bring better cars here. What I can't figure out is why Ford doesn't do the same, and bring the Aussie Falcon and european Mondeo here. Their current lineup is outdated and with the exception of the Mustang, extremely BORING. Get with it, Ford!
#289 of 1278 Re: MPG [rayainsw]
Oct 10, 2007 (11:47 am)
"The Pontiac G8 with the 3.6L V6 engine is estimated to achieve 17 miles per gallon in the city and 24 miles per gallon on the highway. The G8 GT with the 6.0L engine will achieve an estimated 15 miles per gallon in the city and 23 miles per gallon on the highway."
15 MPG is going to be a tough sell, with gas ~$3.00/gal!
#290 of 1278 Re: MPG [wideglide]
Oct 10, 2007 (4:15 pm)
1) Is driving a G8 V8 worth $100 per month more than driving some little box (e.g. Corolla, Spectra, Versa) which gets approximately 25MPG in the city?
2) Is $100 a month enough to even waste time worrying about?
For someone driving 15,000 miles per year (all city, a real worst case):
15 MPG, gas $3 = $3,000 per year
25 MPG, gas $3 = $1,800 per year = $100 per month savings
#291 of 1278 MPG ( actual )
Oct 11, 2007 (2:51 am)
Some people do actually prefer to use less gasoline – for other than purely economic reasons.
That said, I see these numbers as about what I’d expected, though a bit lower than I’d hoped.
Looking at a couple of somewhat similar sized sport sedans with V8s:
The 2008 Audi A8 V8 6-speed automatic is EPA rated at 16 \ 23 – and was rated at 18 \ 25 under the EPA’s ‘old scheme’ for 2007.
The 2008 BMW 550 V8 with 6-speed automatic is EPA rated at 15 \ 23 – and was rated at 17 \ 25 for 2007.
At least the G8 does have a 19 gallon fuel tank.
Having thousands of miles of driving experience with GM’s DoD ( 2005 Grand Prix GXP, V8 5.3L, DoD – now called AFM ) in a V8, I am very curious to find out if this engine & trans combination will allow 4 cylinder operation at higher road speeds than the previous iteration.
In the case of my previous GM car – I believe that the DoD was specifically tuned \ calibrated to engage & provide benefit at speeds up to 60 MPH. Not coincidentally, the highest speed in the EPA test, through MY 2007.
My personal experience, was that if I maintained a cruising speed of 60 or below ( as in heavily patrolled rural areas ) I could maintain close to the EPA highway number. [ = 27, same as my 2007 C6 Coupe w/A6. ] But at anything over 65 MPH or so, DoD would not typically engage – and the MPG would suffer accordingly.
And the point in the fuel mileage vs MPH curve where above a certain MPH, under certain specific conditions, DoD will not engage – seems to result in a sharp drop in MPG. In fact, if such a chart exists at GM, I’d predict that it would show in a discontinuity (??) in the curve. Meaning a straight drop, where DoD disengages, then pick up 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 could achieve 30 MPG, then at 65 it might be capable of 28 and at 70 it might be 26 and at ( theoretically ) 75 it might be 24 and at 80 it might be 22 MPG.
If DoD is actually operable up to about 70, in the real world, but will not engage starting at say 73.14159 MPH for instance, the numbers might then look like this:
60 – 30 (DoD on)
65 – 28 (DoD on)
70 – 26 (DoD on)
75 – 20 (No DoD - instead of 24 if DoD was in operation)
80 – 18 (No DoD - instead of 22 if DoD was in operation)
I am sorta making these numbers up, and I realize the drop is never a precisely linear slope, but I believe these are in the range of possibility \ reality for my GXP, under ideal conditions.
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.
The Corvette developers, based on my 14,500+ miles of driving thus far & in reading many Forum board posts, appear to have assigned more equal weight to MPG in real world driving. And ( obviously ) DoD is not an issue.
For the same example speeds as listed above, I’d estimate my Corvette at something like:
60 – 34
65 – 33
70 – 32
75 – 30
80 – 28 [ = still over EPA highway of 27 ]
Just my $0.03 worth – adjusted for inflation.
Still enjoying the drive – and not obsessing about MPG . . (?)
#292 of 1278 Re: MPG [fsmmcsi]
Oct 11, 2007 (4:03 am)
I could probably live with it, for the performance. However - $1200/year is NOT an insignificant amount of money. If I had a long commute (I'm semi-retired), it would probably be a deal breaker. Kudos to you, if it is, but it is NOT insignificant to me. Or to a lot of other people, which was my point of a "hard sell"... That will put off a LOT of people from buying. That's why large SUV sales are way down, and many are dumping their SUV's to get something more efficient. When you've got a mortgage, kids, etc. etc. etc., that 15 MPG on the window sticker is a big red flag.
And 17 MPG from a V6 is just awful.
#293 of 1278 15 \ 17 city MPG V8 V6, etc
Oct 11, 2007 (4:43 am)
Perhaps an even more telling comparison here regarding the G8 V8 is the ( new for 2008 ) BMW 535i.
[[ BTW: I am WELL aware that each sedan I have mentioned here is substantially more expensive than the G8 V8, with the 535 starting at $50K or so – and I ** WILL ** be taking that into consideration at purchase decision time . . . ]]
The 535 is EPA rated at 17 \ 26 – and offers very nearly the same acceleration as the 550. With that 550 at 15 \ 23. The Edmunds 535 test reported 0 to 60 in 5.5 seconds ( A6 trans ) and the Quarter in 14.0 just over 100.
In this context, the G8 V8 with a rating of 15 \ 23 seems "OK" - to me. Not great. Not bad.
One other data point I find interesting is the 2007 ( no 2008 numbers available yet ) Honda Accord V6 ( not the Hybrid ) with ratings under the 2008 scheme of 18 \ 26. Compared to 17 \ 24 for the G8 V6. If the G8 in other respects appeals, I do not see 1 MPG in the City EPA rating as likely to be a ‘deal breaker’ for most. [[ The actual 2007 sticker for this Accord was 20 \ 29. ]] A 1 MPG difference between the Accord V6 and G8 V6 ( assuming the rating translated exactly to actual driving ) would mean, in 15,000 miles of ( all city ) driving:
2007 Accord V6 = 18 MPG, gas $3 = $2,500 per year
G8 V6 = 17 MPG, gas $3 = $2,647 per year
G8 V8 = 15 MPG, gas $3 = $3,000 per year
Using these assumptions, the Accord’s gas consumption would cost approx $12.25/month less than the G8 V6, and not quite $30/month less than the G8 V8.
Assuming ‘base’ G8 V8 at $30K vs the ‘base’ BMW 535i at $50K – well I can drive a loooooong way on $20 grand worth of gasoline. . .
The remaining questions ( for me ) regarding the G8 are actual dynamics ( acceleration, trans. behavior, braking, handling, ride, fit & finish, etc. ) of production V8 examples.
It appears that published reports by Edmunds & the Monthlies are likely 2 months away, at least. And a test drive is likely 3+ months away.
Waiting for those future events, oh so very patiently . . .
#294 of 1278 Rear Spoiler
Oct 11, 2007 (7:20 am)
I ws dismayed to relize eve the six cylinder is going to come standard with both hood vents and a real spoiler...That's probably a deal breaker for me...
#295 of 1278 Re: MPG [wideglide]
Oct 11, 2007 (7:24 am)
Wideglide: Doesn't it seem that someone who can not even afford to buy the gasoline for the car has no business being in the showroom looking at a new car? Doesn't it also seem that such a person has no business looking at a high performance sedan?
By the way, when younger, I had bought into the whole debt sales pitch of the lenders (buy now, pay latter, your income will go up in the future, etc.), but now have no dedt (except mortgages on two rental houses) and buy vehicles with cash.
The key point with regards to the G8 is that it should not be targeted to buyers who can't afford it. There are plenty who can afford it, and GM and their dealers will do far better if they focus on those buyers.
As for Accords and other front wheel drive car, GM and their dealers need to focus on the vast superiority of rear wheel drive (and yes, I grew up in St. Louis,a nd lived there and in DC until I was 32, so I have driven plenty of RWD cars in snow, and I did just fine in the winter with good tires and a limited slip rear, and tires and RWD vehicles sold now with stability control and so forth are even better for winter driving).
#296 of 1278 Re: 15 \ 17 city MPG V8 V6, etc [rayainsw]
Oct 11, 2007 (11:23 am)
Though these MPG's are speculative, isn't the G8 going to be running on regular gasoline, when other's like the G35, Lexus and some run on premium? And where did you guys get $3/gallon? That's abusive... we're not even $2.75/gallon for premium in Atlanta.