There's little question that our 2008 Pontiac G8 GT possesses solid sporting credentials. I've been curious to find out how well the G8 could serve as a family sedan, however. So over the holiday break, I packed up the G8 and made a trip to visit my in-laws. Overall, I was pretty impressed with the G8 in regards to family-carting duty. Some specific observations about fuel economy, comfort and utility follow.
The Trip and Mileage
We (my wife and 1-year-old) put about 700 miles on the G8, most of this coming in the form of highway driving (70 to 80 mph) from our home in central California down to southern California and back. For the trip, I averaged 19.8 mpg. (The EPA's highway is 24 mpg.) Using the in-car mpg gauge, I noticed city mileage (for me, anyway) sinks to about 11 or 12 mpg. I managed the G8's best tank so far on this trip, 22.6 mpg, as well as its furthest distance on a tank, 351 miles.
Seat Comfort
I found the front seat to be adequate in terms of comfort but nothing more. My wife sat in back for the trip (to be with our daughter) and commented favorably about the copious amount of rear legroom and comfortable seat bolstering. (Note: the front passenger seat was not occupied.) Specific comments: 1) Sitting in the middle of the rear seat sucks because of the high hump for the driveshaft. 2) The rear head restraints aren't adjustable, but they're high enough so that most adults should be OK.
Ride Quality/Noise
In this regard, our G8 GT isn't as comfortable as other midsize sedans. The ride is firm, though I'd say it's acceptable given the car's performance. Wind, tire and engine noise are also more noticeable than on other top sedans during highway driving.
Baby Seat
At first, I intended to install our daughter's car seat in one of the outward seating positions. However, our G8 is lacking LATCH anchors on both sides. I thoroughly dug into the bolstering to check, and couldn't locate them. It seems that the LATCH installer guy was out taking a whiz when our G8 rolled down the line. Fortunately, there are anchors for the middle position, and that's where I put the seat. Due to noticeable rake of the seat cushion, I had to place towels under the seat so that it would rest properly. Overall, the G8 isn't as car-seat friendly as other sedans I've driven.
Trunk Space
We had a lot of stuff to take on this trip. The G8's trunk, at 17.5 cubic feet of capacity, is a couple cubes more than most midsize family sedans'. The trunk doesn't seem as tall as other cars, but the extra length allowed us to fit a large suitcase, a medium cooler, a children's playpen, two duffel bags, a garment bag and a few other small items. The rear seats don't fold down, but there is a pass-through. The trunk lid is supported by struts.
Minor Complaints From the Trip
There's no exterior trunk lid release. The air vents don't adjust enough. The HVAC's recirculation didn't always seem to be doing its job properly. The window switches are sticky, making it hard to just crack open the windows from a close (they act as if you want express-down.)
Overall
I really liked having our 2008 G8 for this trip. If I had to drive a family sedan daily, I'd seriously consider it. And theoretically, the G8's fuel economy isn't that bad -- its combined EPA is 18 mpg, and a Malibu with the 3.6-liter V6 is at 20 mpg -- though I think we're finding that it's hard to meet EPA numbers with 361 horsepower on tap.
I'd say the G8 is a niche choice. If you're into performance, you'll love it. But because of the fuel economy and collection of annoyances, I'd say most people are going to be better off with more mainstream choices.
Brent Romans, Senior Automotive Editor @ 6,291 miles
toyzm says:
06:25 PM, 07/ 8/08
This picture reminds me of GTA San Andreas. G8 looks like a bad boy messing around the family cars.
limeman says:
08:03 PM, 07/ 8/08
Try driving at the speed limit (not 70 mph and 80 mph) and you'd increase your Hwy and overall mileage considerably. Even Edmunds own editors have proved this fact in all types of cars and trucks in a recent report. In some G8 blogs, actual owners who are driving at 65mph on the Hwy are reporting between 24-27 MPG. That is amazing considering the HP and power of this car.
huyracing says:
08:30 PM, 07/ 8/08
for the money, i'd get a G35. sorry GM.
carmizvi says:
09:08 PM, 07/ 8/08
Diesel or hybrid, anyone? I can't help but think that so many "great" cars with otherwise cruddy fuel economy might be saved by advanced powertrains. Scaled out over multiple platforms, they might even be implemented affordably.
mustang5507 says:
10:36 PM, 07/ 8/08
Funny because in the parents' Jaguar XK8 and even my S-type 4.2L, highway cruising between 70 and 85 can net anywhere from 26-31mpg. No lie. Drive one and see =)
1487 says:
05:45 AM, 07/ 9/08
"Diesel or hybrid, anyone? I can't help but think that so many "great" cars with otherwise cruddy fuel economy might be saved by advanced powertrains."
Its hard to get great mileage with 361hp. Check out the mileage on other V8 cars for reference. Anyone looking at the size and hp of this car should know immediately its not as efficient as a 3500lb midsize V6 sedan. The G8s mileage can only be compared to cars with over 300hp. It barely lower than the G35 even though it has far more torque and interior space.
dougtheeng says:
06:01 AM, 07/ 9/08
"This picture reminds me of GTA San Andreas. "
I would agree - crazy eh?
jaguar36 says:
06:46 AM, 07/ 9/08
This is a great post, I really appreciate all the details. Shame the only thing most people seem to care about these days is fuel economy.
vacagrande says:
07:08 AM, 07/ 9/08
I'm surprised at the low highway mpg - usually cars with the LS-series engines are relative misers on the highway. If they just offered the T56 6-speed, you'd see high-twenties mpg on the highway. I was always mad that my roommate's Trans Am got better mileage than my Maxima.
ahightower says:
07:20 AM, 07/ 9/08
Beat me to it, v. Put in a manual with a really tall 6th gear.
Or, you know, get the V6. If the CTS can be cool with a V6, why not this too?
joefrompa says:
08:10 AM, 07/ 9/08
First off, these website comments adjustments stink. Go back, edmunds.
That combined mileage isn't all that bad for the car, but if it's primarily highway then that's a little scary. This car definitely needs a 6-speed.
Great post overall. The LATCH thing is kinda weird. The comments on the windows switches actually sound very familiar with me.....many manufacturers seems to struggle with creating window switches that are easy to operate between small adjustments and express up/down. Honda has done it well, at least in my car. BMW too.
Joe
cocarguydj says:
08:10 AM, 07/ 9/08
Just a couple of notes from G8 owner.(I bought one for my wife a couple of months ago.) The car does have outboard LATCH points, but they are not in the bolstering where the author was looking. There are a couple of openings on the lower back portion of the seat on each side that are held closed by velcro. You have to open these in order to find the LATCH points that are behind them. As for the mileage that the Inside Line staff is recording on this vehicle, it is substantially lower than what my wife and I have experienced. We have averaged 17 mpg over the life of the car with almost exclusively in-town driving and getting into the trottle for fun a reasonable amount of the time. We haven't taken it on a highway road trip just yet(leaving tomorrow morning for the first one), but based on the little bit of highway driving that we have seen, it should be in the mid-20s. The Inside Line staff must be having a huge amount of fun with the available 361 horsepower. I will be interested to see how soon they have to replace the rear tires.
jaeger1 says:
09:28 AM, 07/ 9/08
The observed fuel economy is pretty disappointing, IMHO. Those speeds were hardly excessive.
altimadude00 says:
09:53 AM, 07/ 9/08
No offense to Europe, but diesel + sports sedan just doesn't work over here.
If I can afford a V8, I can afford the gas to feed it.
rayainsw says:
10:58 AM, 07/ 9/08
"No offense to Europe, but diesel + sports sedan just doesn't work over here."
We shall see - as BMW is apparently
going to market a 3 w/diesel...
Over 400 TQ.
- Ray
Hmmm.......
lsxcellent says:
01:44 PM, 07/ 9/08
I have a question for the Author...
Was there any serious altitude gain/loss during your drive? If you were driving at elevation (easy to do in SoCal) then that would seriously impact the overall mileage.
Its also good to hear that there are LATCH points all the way around.
~LSx
louiswei says:
01:51 PM, 07/ 9/08
"First off, these website comments adjustments stink. Go back, edmunds."
Joe, you ain't kidding, this new update is HORRIBLE!! My eyes hurt by looking at the comments and not having the "unread" fuction is so annoying...
Come on, bring the sexy back!!
thegrocer says:
02:05 PM, 07/ 9/08
If you're looking at fuel mileage, this is not the car for you. Really. Go buy a four cylinder Accord or Camary and leave us V-8 junkies in peace.
However, having owned two big V-8 American cars, the mileage doesn't surprise me...although it seems the extra HP cancels out the two extra gears in the tranny considering my '94 Roadmaster got 15 in the city and 23 or so on the highway.
Brent Romans says:
03:08 PM, 07/ 9/08
There was an elevation change during my drive, though I don't think it made a huge difference in terms of the overall numbers. A greater difference (perhaps up to 25 percent or so) would have been realized had I driven no more than 70 mph, which is something we learned in our "We Test The Tips II" article.
http://www.edmunds.com/advice/fueleconomy/articles/125158/article.html
-Brent
mnorm1 says:
07:21 PM, 07/ 9/08
louiswei, joefrompa
Amen on the website. It's change, but not an improvement.
bimmerjay says:
10:48 PM, 07/ 9/08
Yes, someone please fix this awful "improvement" to the blogs.
1487 says:
06:25 AM, 07/10/08
"not having the "unread" fuction is so annoying..."
YES!!!
Did it ever occur to look in the manual to figure out how to install the child seat properly? This isnt the first time IL has said a car doesnt have a particular feature only to be corrected by an owner. This is why the car has an owner's manual. Remember the post about the Aura not being able to display km/hr on the speedo?
dasko says:
11:59 AM, 07/11/08
@ huyracing
"for the money, i'd get a G35. sorry GM."
A G35 offers comparable interior and trunk space to a BMW 3 Series. The G8 is almost identical to a 7 Series according to EPA figures.
cocarguydj says:
06:28 AM, 07/15/08
Just a quick update on fuel mileage from my road trip over the weekend in my wife's G8 GT. I filled the car up three times over the course of the trip with the following numbers (Average Speed/Average MPG):
54.8 MPH/24.5 MPG - 318.41 miles
42.8 MPH/23.3 MPG - ~346 miles
63.2 MPH/23.7 MPG - 368 miles
This driving was all done on regular gasoline, not premium. It also occurred in Colorado/Utah with two trips over the continental divide (first and third tanks)with several excursions into triple digit range, typically for passing purposes, and speeds in the 70-85 MPH range most of the time. The second tank included a fair amount of in town and rural road driving (~40MPH) with stop signs every few miles.
Overall I really enjoyed the road trip in the car and was fairly impressed with the mileage considering the available power.