Pontiac marketing has answered a nagging question as to what the fuel economy numbers are going to be.

V6 17 city, 24 highway
V8 15 city, 23 highway

I believe these are estimates by GM and not official EPA numbers but the EPA test is like not asking a question unless you already know the answer.

achieftain: Do you have the link to where you got this info?

Here are the official Holden figures for our VE's -

http://www.holden.com.au/pdf/chooseavehicle/techdata/GM_Holden_fuel_economy_VE.pdf

So the SSV auto is listed as 14.3l / 100km which equates to 19.754 mpg

and the SV6 auto is listed as 11.3l / 100km which equates to 25.00 mpg.

So what the hell does the AFM do??? Those aren't far from what my 05 F-150 w/o AFM got! Guess this is the price you have to pay to get a V8.

Well we also have to take into consideration that starting with 2008 models the EPA is measured differently to give more real world numbers. So in comparison with other models make sure its 2008 to 2008.

Displacement on Demand for the V8.......I don't see that accounted for.

Displacement on Demand for the V8.......I don't see that accounted for.

It's accounted for in the fact we only get that version of V8. It is difficult to directly compare Australian mpg figures to ours since the test procedures are different.

It's accounted for in the fact we only get that version of V8. It is difficult to directly compare Australian mpg figures to ours since the test procedures are different.

True. I really do expect the manual GT to return about 25mpg on the highway. I'd be a little ashamed if it gets fewer miles per gallon than my Dad's old 1995 Impala SS, which typically gets 25-26 on the interstate!

In the 6 speed GTO, I get 26ish on the highway. I'd hope both 6 speeds (auto and manual) would get at least 26 with AFM.

car and driver said:
PROJECTED FUEL ECONOMY (C/D EST):
EPA city driving: 17–19 mpg
EPA highway driving: 25–26 mpg

any truth to this?

In the 6 speed GTO, I get 26ish on the highway. I'd hope both 6 speeds (auto and manual) would get at least 26 with AFM.

I expect that the G8 V8 might be able to manage ‘26ish’ on highway runs – if driven at the same speeds as your GTO, when it now sees 26ish - given that the 2004 GTO 5.7L ‘would have’ posted 16 / 26, under the EPA’s new scheme [ actual sticker was 17 / 29 ] ** IF ** you drive at speeds where AFM \ DoD will engage in the G8 V8. If driving at speeds above AFM engagement, I’d guess more like 22 – 23. One thing I want to know before making a purchase decision is what maximum cruising speed is possible on real world highways before AFM will not engage.

And the 2006 6.0L GTO ‘would have’ shown an EPA rating of 15 / 23 [ actual sticker was 17 / 25. ]

The new ‘official’ EPA rating for my 2007 6.0L Corvette ( 6-speed automatic ) ‘would have been’ 15 / 25, though the actual sticker \ 2007 EPA rating was 17 / 27. And I can manage 28+ MPG on any long highway run, even at 70 – 80 MPH. Without AFM \ DoD.

But this sort of variance between EPA and ‘actual’ MPG, particularly with AFM thrown into the mix, is one primary reason I’ll be waiting to read initial owner’s experiences & feedback before I make a buy decision . . .

We shall see – but not for at least another couple of months, it appears.
YMMV.
- Ray
Very pleased with the Corvette’s ‘actual’ MPG . . .

The mpg isnt too bad considering that its a big V8. A 08 camry with over half the horse power and half the cylinders achieves 21/31. If you are worried about EPA numbers get a Corrola.

I noticed today that the new Audi S5, 6 speed manual trans., 4.2L V8 is EPA rated at:
14 \ 21.
And only has a 16.6 or 16.9 gallon tank.
Yikes......

My g8 got 18.5 first fill up, both city and hwy combined, that includes a little hard driving also, well lots of full throttle shifts to see if I could get the tranny to shift like it should in manual or sport mode. Still screwed up in my opinion.

G8 GT - 212miles
40% hwy 60% city regular 87 avg 20.3

I have been driving my G8 GT #677 of 888 for 2.5 weeks or 1,100 miles and have gotten 20.7 MPG highway miles and are now at 20.2 MPG with some city mixed in now. Probably 80% highway and 20% city driving.

I'm at 480 miles and I'm showing right about 14.5 miles average per gallon for now.

My first tank averaged 17.4 mpg. It's consisted of some city stop and go, some rural, some hill climbing but no freeway driving. My GP GXP averaged about 17.7 for the same pattern.

The gas guage said 1/8 when I refueled and it took 15 gallons. However the DIC's range said 43 miles and remaining fuel showed 2 gallons in engineering mode. It's looking like the DIC isn't that accurate or they're sandbagging a little to give us a bit of reserve.

I got it up to 24.7 today. Went over to the dealership for a few things, and they filled up my G8. I reset the DIC, and worked on getting it into half active. Easy on accel, and 25 miles of interstate at 70 mph.

Deja Vu. when I had the 06 GTO people everywhere saying " 22-25 mpg all the time" when I was getting 15 babying it.. and here we go again but now im getting 14 what the hell am I doing wrong.. TELL me please.

Played with my Dic:p this morning on the way to work. Set cruise for 75mph, reset the comp, registered 25.6, then bumped up to 80, reset it and it was 23.3. Hopefully it will be somewhat near those numbers. Pure highway driving, I expect alot of us will see 25+mpg. I dont see why not, my LS1 powered 02' B4C's could knock down 26mpg no problem, cant see why these wont.

I'm going on a 4 hour non-stop drive to Portland on business next week. I'll reset my DIC:p when I hit I-5 and try to keep my foot out of it for awhile at least. I said "try".

First tank: 15 mpg (a lot of idling showing people the car)
Second tank: 20.2 mpg (freeway/city mix)
I didn't buy the GT for the gas savings, although it is much better than my LT1!

I too refueled at an eighth of a tank and it took 16 gallons to fill up. Good reserve! :)

Deja Vu. when I had the 06 GTO people everywhere saying " 22-25 mpg all the time" when I was getting 15 babying it.. and here we go again but now im getting 14 what the hell am I doing wrong.. TELL me please.

I just noticed you were from Montclair. You're not driving the 10 or 60 west bound in the morning are you?

I recently sold in Creekside and moved to Indiana.

I just noticed you were from Montclair. You're not driving the 10 or 60 west bound in the morning are you?

I recently sold in Creekside and moved to Indiana.

the 10 East every morning

Lucky you. I drove to Industry (Azusa) every morning from Haven Ave.

I'm going on a 4 hour non-stop drive to Portland on business next week. I'll reset my DIC:p when I hit I-5 and try to keep my foot out of it for awhile at least. I said "try".
Well, got just under 24mpg going down to Portland, but had some stop & go for awhile since 2 idiots decided they both wanted to be in the same spot at the same time on I-5. Once past that, was able to cruise the next 180 miles at between 65-75 mph. I still don't have 1000 miles on the car yet but I think 24-26 is realistic IF you keep the hammer off the firewall. Not easy to do in this car.

Penguin...is that real, calculated milage, or mileage per the DIC. On my 2002 Vette the DIC reads about 1.5 HIGHER than my true mileage.

By actual gallons put in the tank, getting 18.5 for the 567 miles on the odometer. Mostly rural roads, no sustained highway driving.

Mine would do better if I didn't nail it so much. I need to work on that the next tank. Still getting in the mid to upper teen. I'm working on my intake and thats why I've been getting on it so much. Need to put an egg under the gas pedal. I'm getting old and afraid if I don't go fast now, I might not be able to later.
locrzn

What Octane fuel is everyone burning in their GT?

This is from one web site discussing preimum fuel. I have read other articals saying it is recommend to use high octane by GM in the GT.

- 5,967 cc 6.0 liters V 8 front engine with 101.6 mm bore, 92.0 mm stroke, 10.4 compression ratio, overhead valve and two valves per cylinder L76
- Premium unleaded fuel 91
- Multi-point injection fuel system
- 19.2 gallon main premium unleaded fuel tank 16.0
- Power: 269 kW , 361 HP SAE @ 5,300 rpm; 385 ft lb , 520 Nm @ 4,400 rpm

So your 02' Vette reads high? I wondered why when I brought my 04'GTO to FL and drove my 02' Vette back to IA, that my mileage differential was several MPG in favor of the Vette. Both are 6spds. I get 15-16 around town (lots of 45-50 mph, stop and go's w/ lloonngg light times) with the GTO here in Naples. So far, the G8 GT is doing about the same in similar driving with about 200 mi. on it.

RRM

Penguin...is that real, calculated milage, or mileage per the DIC. On my 2002 Vette the DIC reads about 1.5 HIGHER than my true mileage.

I think they have improved since the C5s on the accuracy of the readout. I had C5s and agree with your above statement. I have since had an 06 coupe and now have an 07 Z06. Both are dead on it - the DIC is very accurate, as I compared it to doing it the manual way several tankfuls on both vehicles. I was impressed in the improvement from one generation to the other. Hopefully the G8 has the more accurate DIC readout also.

The other thing GM has improved on in the G8 GT is the accuracy of the Speedo. MY GPS says it's spot on with the stock 19"s. My GTO on the other hand is 2-3 mph off, at speeds over 35 (reads fast- going slower than reading).

RRM

The manual says "regular" for the L76. However, not all fuel is actually rated correctly. With ethanol blending, the actual or effective octane rating of a fuel listed on the pump as 87 may be effectively closer to 89 or 90 in some cases. Use what doesn't ping. I have about 1,000 miles on my GT with regular and it sounds fine although I haven't really pushed it very hard under load yet.

my fuel economy numbers went up! I wonder if its because Im getting more miles in the car i have 1500 miles now.... or will it be the new magnaflow mufflers but last night on the freeway I got bout 30 mpg at 70 mph average... thats a pretty big jump
Im at 24 mpg right now combining city and freeway and having a sum fun with it but still 24 is pretty good i would say..

my fuel economy numbers went up! I wonder if its because Im getting more miles in the car i have 1500 miles now.... or will it be the new magnaflow mufflers but last night on the freeway I got bout 30 mpg at 70 mph average... thats a pretty big jump
Im at 24 mpg right now combining city and freeway and having a sum fun with it but still 24 is pretty good i would say..

Wow... Hugo are you hitting the reset button while your on the freeway..?
Those numbers look to good to be true.

Thanks,
RJ

Are you using real data or the DIC for your MPG?

I track mine by actual fuel consumed and these are my figures.

Gallons Cost Total Miles $/Gal Cost/Mile Range MPG
15.22 $45.50 277 2.989 0.172 331 17.4
14.85 $45.13 567 3.039 0.156 371 19.5
15.95 $49.26 897 3.089 0.149 393 20.7


15.34 46.63 3.039 0.159 365 19.2 Averages+


Sorry about the format, lost it when the message is posted.

Ya i reset it right before i got on the freeway I drove about 20 miles.. like the first couple miles i got a 34 mpg reading which i knew wasnt right but after 20 miles was still in the 30's but I'll try again tomorrow and i'll post a picture maybe it was just a lucky day or the DIC is playing tricks on me haha

I've checked the DIC fuel mileage to my own calcs and found them very close. So far, on pure hwy trips IU'm getting 23.5-24.2 mpg with a 72-74 mph average, windows up, air condition on - all on pretty flat midwest highways. I'm very impressed so far. For more mixed driving, I get about 18 mpg.

Are you using real data or the DIC for your MPG?

I track mine by actual fuel consumed and these are my figures.

Gallons Cost Total Miles $/Gal Cost/Mile Range MPG
15.22 $45.50 277 2.989 0.172 331 17.4
14.85 $45.13 567 3.039 0.156 371 19.5
15.95 $49.26 897 3.089 0.149 393 20.7


15.34 46.63 3.039 0.159 365 19.2 Averages+


Sorry about the format, lost it when the message is posted.


If you quote your post the #'s line up good.

But you should be considering yourself lucky that you can get gas that cheap. It hasn't been $3/gal here for quite awhile now.

Regular is $3.80-$3.90/gal (87)
Midgrade is $3.90-$4.00/gal (89)
Premium is $4.00-$4.20/gal (92)
Diesel is $4.20-$4.40/gal

And I am in Wisconsin, not California like most people assume :banghead::banghead:

If you quote your post the #'s line up good.

But you should be considering yourself lucky that you can get gas that cheap. It hasn't been $3/gal here for quite awhile now.

Regular is $3.80-$3.90/gal (87)
Midgrade is $3.90-$4.00/gal (89)
Premium is $4.00-$4.20/gal (92)
Diesel is $4.20-$4.40/gal

And I am in Wisconsin, not California like most people assume :banghead::banghead:

Gas is no longer that cheap! It's up more than 10% since originally posted.

I've checked the DIC fuel mileage to my own calcs and found them very close. So far, on pure hwy trips IU'm getting 23.5-24.2 mpg with a 72-74 mph average, windows up, air condition on - all on pretty flat midwest highways. I'm very impressed so far. For more mixed driving, I get about 18 mpg.

I sure hope these numbers IMPROVE as the car gets broken in. On a flat interstate highway my 2002 Corvette will get 31 MPG. I was hoping to see the G8 getting at least 28 to 29 under simliar conditions.

This time in 2001 gas was averaging in the $1.40's...that's when I was running with nothing but V8s in the family! Them days is over for me...so i'm now saving up for the G8GT to be the only V8...the rest are 4 and 6.

Regular was $3.72 near the house...some stations are already at $3.85....I'm scared.:oldfogey:

If you quote your post the #'s line up good.

But you should be considering yourself lucky that you can get gas that cheap. It hasn't been $3/gal here for quite awhile now.

Regular is $3.80-$3.90/gal (87)
Midgrade is $3.90-$4.00/gal (89)
Premium is $4.00-$4.20/gal (92)
Diesel is $4.20-$4.40/gal

And I am in Wisconsin, not California like most people assume :banghead::banghead:

Man, you're getting hosed where you are....Gas was 3.54 for regular when I drove to work in Neenah this morning. I loaded up premium (93) yesterday for 3.66.

I'm showing about 19.8 this tank and I've been on it just a bit. Still taking people for a ride. I did notice the my car doesn't run a good with the new wheels. They are probably just a little heavier then the 18's and the rear tires are just a little taller. I'm hoping when I get my cai finished next week it will pick back up. I've gotten as low as 15.5 on a recent fill up. The temperature has gotten a little warmer here in Missouri, that could have something to do with it. I think its mainly the wheels. Don't put to big a wheel on if you want to keep your performance and mileage. All these guys who want to put 22's on their cars are gonna get a big surprise, I put 22's on my 300 and killed it, lowered it and looked great, but, lost a ton of power and didn't stop as well either. We are at about 3.43 per gallon and that sucks.

Mines about 16mpg on 92 octane. only 250miles on the clock though.

Just filled up with 334 miles on the ticker, 17.15 gallons comes in at 19.47 mpg. That was with about 200 miles highway and the rest stop and go and probably to much wot. I trying my hardest to stop the wot since gas is so high. I may have to go to wot rehab.

I sure hope these numbers IMPROVE as the car gets broken in. On a flat interstate highway my 2002 Corvette will get 31 MPG. I was hoping to see the G8 getting at least 28 to 29 under simliar conditions.

One thing you gotta remember is that the G8 is a heavy car compared to your Vette. 31XX pounds versus 3995? pounds. Heck, I bet if the G8 shed 20% of its weight, it'd be right there around 28-29 mpg.

Just filled up with 334 miles on the ticker, 17.15 gallons comes in at 19.47 mpg. That was with about 200 miles highway and the rest stop and go and probably to much wot. I trying my hardest to stop the wot since gas is so high. I may have to go to wot rehab.

Just remember, rehab is for quitters:D.

See my message on above Vector post. Just arrived from 1640mi trip. VMS ECM installed, 93 octane, no other mods. 23.3mpg! Wife driven - no cruise control - 69mph ave. following my SUV. Headwinds - Got 24.2mpg on first 700mi of trip. G8 had 520m on ODO at start.

23.3MPG!!!!!

RRM

I just got 17.0MPG on my first tank of gas on mine and I did a good bit of playing as well as about 2-3 hours of almost stopped traffic. My average speed was 32mph if that tells ya how long I was idling in traffic lol. I love this car!!!

If you want to get better MPG get a Magnacharger!!!!

BLOWNCHEVY was getting 26MPG with Haddad's G8!!!!

I sure hope these numbers IMPROVE as the car gets broken in. On a flat interstate highway my 2002 Corvette will get 31 MPG. I was hoping to see the G8 getting at least 28 to 29 under simliar conditions.

Your corvette weighs about 800 pounds less than the G8 GT. The G8 GT isn't going to ever see high twenties mpg. And your 2002 vette has a 5.7L 350 horsepower engine unless it's a ZO6 in which case the same size engine makes about 405 hp (under older SAE standards.) The G8 GT has a 6.0L V8 that makes 362 hp, admittedly with active fuel management which should help hwy mpg a little. Despite making more power than a standard last gen vette and having a larger displacement engine AND weighing nearly 4,000 pounds, I can occassionally see mid-twenties mpg. I'd say that's pretty darn good.

I'm assuming your vette is a 6-speed manual, right? Are you going by your onboard mpg meter? Check your actual mileage manually and I'll bet it's more like 28-29mpg.

OK so mines avg at 15.6. I dont speed much i'm more of a quick acceleration type of person. I think its funny when you get a ricer civic or someone in a big ass truck look at your car at a stop and try to accelerate faster than you! haha

I had some idiot in a TC try that crap with me. Made me waste my gas putting him behind me. LOL

Just completed 1300 miles, all but about 100 on the interstate system, cruize control set at 79-80, an occasional burst to 100 to get around traffic plugs, got 21.3 mpg on 87 octane. Car has just over 3000 miles on it now.

+1
87 octane i get 21.4 -22.2 (70-75mph) on HWY only
91 octane i get 24.5 -25.1 (70-75mph)

Drove my car from DFW to Houston (about 400 miles) and averaged 25 mpg's on the way down and 24 on the way back running 93 octane. (lower quality gas on the trip back, I think) I had the cruise set at 75 and made no stops.

lower but still 93 ?

yep, still 93. Didnt drive the car any different. No wind...no traffic (amazing for Houston)...had to be the gas.

Your corvette weighs about 800 pounds less than the G8 GT. The G8 GT isn't going to ever see high twenties mpg. And your 2002 vette has a 5.7L 350 horsepower engine unless it's a ZO6 in which case the same size engine makes about 405 hp (under older SAE standards.) The G8 GT has a 6.0L V8 that makes 362 hp, admittedly with active fuel management which should help hwy mpg a little. Despite making more power than a standard last gen vette and having a larger displacement engine AND weighing nearly 4,000 pounds, I can occassionally see mid-twenties mpg. I'd say that's pretty darn good.

I'm assuming your vette is a 6-speed manual, right? Are you going by your onboard mpg meter? Check your actual mileage manually and I'll bet it's more like 28-29mpg.

I guess I have higher expectations than you do. I don't see 6.0 as significantly bigger than 5.7, so that combined with AFM, I want to see an increase in mileage, everything else being equal. Case in point, my LT1 powered Chevy Impala SS... When the engine was changed from a 350 to a 383, mileage dropped only slightly most of which is attributed to my heavy foot, constantly smoking the tires.

You are correct, the G8 is several hundred pounds more than a Vette, hence my concession to being happy with 28mpg. Anything less than 28 is going to be a disappointment in my book, but I guess I'll just chalk that up to my personal gripe list along with the Atari console display.

+1
87 octane i get 21.4 -22.2 (70-75mph) on HWY only
91 octane i get 24.5 -25.1 (70-75mph)

Thats well worth the 20-30 cent price increase for premium in most areas. I know my friends and I have had similar results with our cars too but its always hard to get an exact estimate. Usually premium is worth it just for the piece of mind.

I have 39miles on the car, and got 28mpg on the highway yesterday!
What a car!!

I just picked up my 2009 G8 GT 2 days ago and drove it a little over 300 miles this weekend. It was mostly interstate driving and I got 24.3 mpg on the first tank of gas. The info on the DIC was telling me it was getting 24.5mpg.

I also have a 05 GTO with a 6 speed. I usually get around 22 overall.

Just drove from Chattanooga Tn, to Gulf shores Al, and back. It's about 420 miles. I was able to make it on 1 tank in one direction believe it or not. On the way down I got 25.5 mpg verified by Fill up, readout was only .2 or .3 mpg high. This was going 70-75 except the last 40 miles which were 55 with red lights. On the way back I got 25.2, it is about 700 feet uphill, and I went a little fast on the last leg.

What I did notice is that the car peaks around 62-65. I was able to get the mpg to Read 30 for over 20 miles at this speed with the cruise on. Nearer 70 it was holding 28mpg. Now this is on a very flat section of the freeway. So the faster you go the worse it gets. But at 77 or so you can still pull 24-25. That is from my experience. The only mods I have are Rotofab and HSRK. I did unplug the HSRK for the stock sensor for about 100 miles and saw absolutely no gains or losses.

I have been getting 25.5 mpg i think that is good considering that when I got it it was only getting 13 mpg. I think that someone was a little joy riding at the dealer. lol

G8 V6 Ship WT: 3919lbs. Oct. 21,08= 20.20mpg.~ Oct. 26,08=20.57 mpg.~ Oct. 28,08=18.76 mpg.~ Oct. 31,08=20.78 mpg.~ Nov. 4,08=20.30 mpg.~ Nov. 11,08=16.32 mpg.~ Nov. 18,08=19.46 mpg.~ Average= 19.48 MPG

im at 14.4 on my DIC...yes i do some "spirited" driving but thats not very good

w/e....i still love this car

I had always heard mileage should go up a bit as you put more miles on the car and "Break it in" , however I have not experienced this, and at jwilson54's numbers he has not either. :( I am getting the same mileage today at 5,000 miles as I did at 500.

23-24 here...

Last 800 miles (60% city, 40% open 80 mph freeway) I've averaged 20.23 on premium Shell.

With cruz control locked at 75, I can get 23-24...but in mixed driving its more like 16

I wonder if what I'm getting is normal. I get 16-17 average with 60% freeway/40% city. My freeway speed varies between 75 and 85, and the car has about 1500 miles on it. I would expect the number to be 18-20 with these driving conditions. Since every other car I owned gets right in the middle (or higher) of City/Highway EPA rating in similar driving, this does not seem normal to me.

I wonder if what I'm getting is normal. I get 16-17 average with 60% freeway/40% city. My freeway speed varies between 75 and 85, and the car has about 1500 miles on it. I would expect the number to be 18-20 with these driving conditions. Since every other car I owned gets right in the middle (or higher) of City/Highway EPA rating in similar driving, this does not seem normal to me.


Since you've got a Michigan-registered car, I wouldn't expect your car get past Toledo let alone obtain more than 20 mpg. Just kiddin' - Buckeye joke! :wink2:

I have about 12,000 miles on my car now and have found with 60% hwy/40%city driving, using the cruise control wherever possible on the highway and generally not going to much faster than 72 mph, I can get around 19-20 mpg in the cold weather. I've also found that like most cars, gas mileage seriously drops off after about 72-74 mph. With this car, the AFM rarely kicks in once you are over 70 (I've monitored this on several long drives with the DIC in engineering mode.)

So given you're driving a little faster than I drive on the highway but with similar driving patterns on similarly flat Midwestern roads, I'd say your mileage is about right at 16-17 mpg.

You should for one week try to go no faster than 72 and see what happens to your gas mileage. For kicks, I drove like a granny one tank in the summer and hit 21-22 mpg in mixed driving. That meant going 65-68 on the highway in the right lane. The afm sweet spot kinda seems to be in the 64-68 range with relatively flat roads.

Give it a shot and report back. SOrry for the joke . . .couldn't resist! GO BUCKS!!! :)

Since you've got a Michigan-registered car, I wouldn't expect your car get past Toledo let alone obtain more than 20 mpg. Just kiddin' - Buckeye joke! :wink2:

I have about 12,000 miles on my car now and have found with 60% hwy/40%city driving, using the cruise control wherever possible on the highway and generally not going to much faster than 72 mph, I can get around 19-20 mpg in the cold weather. I've also found that like most cars, gas mileage seriously drops off after about 72-74 mph. With this car, the AFM rarely kicks in once you are over 70 (I've monitored this on several long drives with the DIC in engineering mode.)

So given you're driving a little faster than I drive on the highway but with similar driving patterns on similarly flat Midwestern roads, I'd say your mileage is about right at 16-17 mpg.

You should for one week try to go no faster than 72 and see what happens to your gas mileage. For kicks, I drove like a granny one tank in the summer and hit 21-22 mpg in mixed driving. That meant going 65-68 on the highway in the right lane. The afm sweet spot kinda seems to be in the 64-68 range with relatively flat roads.

Give it a shot and report back. SOrry for the joke . . .couldn't resist! GO BUCKS!!! :)

I think the OSU/Michigan jokes stopped being funny to me after Dick Rod decided to unpucker his NSFW to get Terelle Pryor and you know the rest...

On a more serious note I don't think I could get myself to drive below 75, although I have to say when I lived in Cleveland people went about 5-10 miles an hour slower than here. If you ever drive 23 or 75 North into Michigan it's kind of funny how everyone floors it at the same time right at the "Welcome to Michigan" sign. As far as MPG difference between 70 and 80 mph, I'm surprised it makes that much difference on the G8. My last 2 cars were 6 cylinder and I maybe lost 1 or 2 mpg at most when going 80 instead of 70. Maybe if I put something under the gas pedal so it can only be pushed down 10% at most it will be of some help.

On a more serious note I don't think I could get myself to drive below 75, although I have to say when I lived in Cleveland people went about 5-10 miles an hour slower than here. If you ever drive 23 or 75 North into Michigan it's kind of funny how everyone floors it at the same time right at the "Welcome to Michigan" sign. As far as MPG difference between 70 and 80 mph, I'm surprised it makes that much difference on the G8. My last 2 cars were 6 cylinder and I maybe lost 1 or 2 mpg at most when going 80 instead of 70. Maybe if I put something under the gas pedal so it can only be pushed down 10% at most it will be of some help.

I hear ya about speeds in Michigan. I'm certainly one of those people who typically cranks it up a notch once I see the 70 mph speed limit signs entering Michigan!

I hear ya about speeds in Michigan. I'm certainly one of those people who typically cranks it up a notch once I see the 70 mph speed limit signs entering Michigan!

I also add 10 mph when entering MI....:)

To the point, above 70 mph AFM does not kick in much at all if conditions are not perfect. I also believe cold weather hurts mileage slightly. Over the summer I hit 25 mpg on the DIC on a return trip from Madison averaging just below 70 mph. Last week I hit 21.4 mph with a 75.6 mph average (on the DIC) coming home from southern IL. I was driving into a very strong cross/head wind.

PS I'm writing this from the Blackwell in Columbus, as an NWU grad, while texting with my daughter at UW-Madison. I think I have nearly half the Big Ten Covered in one post!

I wonder if what I'm getting is normal. I get 16-17 average with 60% freeway/40% city. My freeway speed varies between 75 and 85, and the car has about 1500 miles on it. I would expect the number to be 18-20 with these driving conditions. Since every other car I owned gets right in the middle (or higher) of City/Highway EPA rating in similar driving, this does not seem normal to me.
Same boat here. I seem to get 13-14 city, 22-23 highway. Mixed is coming out depressingly low at 17.

I really don't see how these people get 25-30mpg. I only got the 23 when I babied it. I literally couldn't drive slower or more reserved. The 17 mixed was in the rain, too. I drive like a baby in the rain.

Update: I did a cruise control test for a 10 mile stretch of mixed slight hills and turns (highway). I got 26.2mpg. Unfortunately, I had people swerving around me, giving me evil eyes, and I was a complete menace on the road. I had to do a few bursts to get out of the way at times. They really need to rate fuel economy at 70mph, 65mph is dangerous.

I used to get 17.5-19 mpg. Now I'm getting 16mpg on mobil one synth. what gives? Driving hasn't changed at all, so I don't know what's going on. Prolly the air filter though 15k and it hasn't been changed. Buying CAI soon, so I haven't bothered. :P