Low 20's on the highway and around 12-13 in the city.

 

The tuners need to weigh in but I recall reading that they stock tune is a very rich mixture. My nose agrees with this when I start it in the garage. Really thick exhaust which, while totally unscientific, suggests a rich mix.

 

too bad we cant lean them way out on the hyway on long trips like an airplane. (lean of stoich) I bet we could get near 30mpg that way, but make a lot of NOx

 

I wish my V8V got worse milage.... you know.. make it feel even more 'exotic'.

 

OK, that goes a long way toward explaining the poor mileage, at least, on the highway. With over-all gearing that tight, the pumping losses and internal friction are eating up a lot of fuel. I didn't realize that the final drive was so short in these cars. Does Aston really believe these cars are used primarily for drag racing? IIRC, my Challenger turns about 1800 at 75 mph.

This is very disconcerting. I don't think I could put up with that setup. Are there taller differential gears available? If not, I'm probably going to start looking at other options, brand-wise...

 

they definitely run VERY rich from the factory. I've had my car dyno'd and they took AFRs as part of it, and it was pretty damn rich. I'd have to dig out the dyno charts to get the specifics, though.

Edit: here you go

 

I'm getting 12.4 MPG, combined highway and city. My drive to/from work starts on the 6 lane highway but sometimes degrades quickly into stop and go traffic when things get thick during rush hour(s).

 

So far its about 9.4 all the way around. Hopefully it gets a little better.

 

Well, now I'm really depressed. I feel as though I was just about to marry a super model with a sweet disposition, but found out right before the wedding that she was a heroin addict...

Cheers to to all you folks who are willing to accommodate the wildly excessive thirst of these cars. I could never bring myself to do it. You know, I just knew there had to be some hidden fly in the ointment somewhere when I first realized that I could actually afford to buy a car this beautiful...

 

I think something must be wrong with the MPG readout in my dash. Are you guys reporting MPG figures from the readout on the dash or are you actually calculating figures from the amount of fuel being put into the tank?

I seem to get much better (reported at least) figures

FF

 

The 4.7 Vantage is 15% more fuel efficient then the 4.3 . Strange I know...

 

Its only rich, from the dyno, from 6000 to 7000rpm..... nothing to do with MPG. part throttle , cruise, is always near stoich. (i.e. 14.7 mixture average) so, a little rich from 6 to 7K rpm is not really a concern, especially at full throttle. so, nothing to worry about here.
What determines MPG quality, is the rolling friction, and engine efficiency. this engine is not very efficient. Also the RPM range for cruise is way too high. 3000rpm at 80mph is just RPM just used up for no reason. 5th gear can accelerate you to some phenomenal speeds, and 6th should be an overdrive. However, its really about the entire gear ratio set. the rear end is WAY too high, as shown by the way too low, first gear. (no way it needs to be that short of a gear..... something like 10:1) most supercars have an 8.5:1 first gear, and that alone , by changing the rear end by 20%, you would get 80rpm RPM down to 2500rpm or so

 

I have not checked my 09 yet, but my 07 Vantage gout 15MPG in town (Minneapolis traffic is pretty bad at times) and between 20 and 22 MPG on trips when I kept the car at 70 to 75 MPH.

 

V12V 12-13mpg in town and 17-18mpg on the highway

My previous 4.3L V8V really wasn't much better than that.

 

Not as high as my SPG (Smiles per Gallon)!

I get about 21 on a highway trip. 8 when playing around town.