Why isn't the fuel economy better?

[FRiSson]

On my previous Honda, I got MPG way better than the car was rated. I calculated my expected mpg for the MT FR-S using the same ration. I anticipated an average rating of 29mpg average and 34.5 highway. Turns out that is exactly what I am getting.

The US EPA uses a system for calculating mpg that seems to underrate MT cars and overrates Automatics. But I think it is very tough to come up with a algorithm that would be 90+% accurate.

The best way to determine the MPG of a car, is to determine the ratio between the EPA mpg that your last car received and your actual real-world mpg. Now apply that ratio to the EPA estimates of the car you are considering.

[jarviz]

hit the treadmill and you can easily get your mpg up!

Originally Posted by TVC15

Simple -
When I drive like a fool, I'm getting 23 - 24mpg.
When I drive like a gentleman, I'm getting 30 - 32mpg

I'm more gentlemanly than you because I'm getting 34-37mpg when driving sane

[gdi2290]

my friend in his FR-S gets 24mpg while I get 27mpg in my BRZ

[smbrm]

Originally Posted by Vracer111

It really depends on how you drive the car...stay off throttle as much as possible and keep the rpms low and you will get better fuel mileage. Personally I can't do that, once the car is warmed up 5k-7k rpm is my shifting range much of the time...average about 22-24 mpg daily, sometimes 20 mpg. I did recently get 33 mpg (calculated at fuel stops) fairly consistently during an ~3,500 mile round trip on vacation - which is not bad considering my FR-S has maximum performance sticky tires (in stock size, aired to 45 psi for the trip), uses 10-W30 weight oil, and had 200+lbs of cargo with me. Also seemed easier to get 33 mpg in the mountains than on flat interstate, though in the flatter interstate regions it was getting the 33 mpg at 80 mph (cruise set at 3.5k rpm) versus about 70 mph up in the mountains.

On a previously reported observation, I shared that for a 107.9 km journey from the edge of the city, through the foot hills to the edge of the mountains, pretty hilly, 100-110kph. I calculated based on a top up, 5.0 litres/100km. 46.9 miles/USG! Premium 91AKI V-Power.

Now where I am doing like 90-100% city I can observe between 26-30 miles/usg . It only takes a few heavy footed accelerations to move the single tank average quite a bit.

I agree it really depends on how you are driving!

[hippari]

I always drive like a douche, but I'm still averaging 28ish. It's a godsend, my 1.8 liter miata was giving me low 20's...

[SuperDave]

Originally Posted by industrial

Everyone here that is complaining is forgetting about the ridiculous emissions and safety requirements oems have to meet.

You want great mpg? It's easy, remove the cats and lean out the fuel maps. Probably get 35mpg easy with +20hp.

how would the removing the cat converter increase fuel efficiency?

[Celica00]

Originally Posted by SuperDave

how would the removing the cat converter increase fuel efficiency?

i'm not pro at this but doesnt it block airflow in the exhaust to an extent? w/ no cat, the engine flows more free.

[einzlr]

Originally Posted by Veloist

I live in a hilly place where my MPG's are always lower than EPA's estimates. For instance, my Prius is currently averaging 43mpg compared to 50 mpg estimated. My family owned a Scion xD that averaged 22mpg, and as of now our FR-S is averaging 23mpg which I'm quite surprised about, but happy with.

Ride the brakes going down hills in the Prius and let the regen do its thing

[MVJ1975]

I get about 25mpg in my 6AT, but a) all of my driving is city/surburban that rarely gets me above 55 for anything more than a minute or two and b) I drive like a hooligan.

I'd say that's pretty good, considering. If you drive like everyone else and treat the gas pedal like a pressure-sensitive landmine, you'll get great gas efficiency.

[einzlr]

Originally Posted by White Shadow

Forget the price of the car. The reason I chose to compare the 328i is because it has a 2.0L 4-cylinder engine, although it's also turbocharged. I'm just surprised that the BMW has an engine with the same displacement, pushing a much heavier car, and still has a significantly higher highway fuel economy rating. But like others have said, real-world mileage can vary. Maybe the ratings are misleading.

Car makers are very EPA-conscious these days. This is in part due to fear of CAFE and in part due to recent consumer demand where 40 has become the magic number, as in 40mpg hwy. Therefore, BMW and others deliberately target these ratings, going to great lengths to fully analyze and exploit the details of how EPA numbers are reached. By contrast, EPA ratings clearly were not a priority - probably not even a consideration at all - in the design of the twins, and the 30+ mpg that some people are getting is just a happy perk.

[Trojan_SC]

Seriously?

[White Shadow]

Originally Posted by einzlr

... By contrast, EPA ratings clearly were not a priority - probably not even a consideration at all - in the design of the twins...

CAFE is an average for all the cars a manufacturer sells. It's very important to all manufacturers to keep their average fuel economy up to meet CAFE regulations. Trust me, Toyota & Subaru didn't ignore fuel economy on these cars!

[Rayme]

More people seem to get around 28-32, including myself.

http://www.fuelly.com/car/scion/fr-s

[Turbowned]

Originally Posted by White Shadow

Forget the price of the car. The reason I chose to compare the 328i is because it has a 2.0L 4-cylinder engine, although it's also turbocharged. I'm just surprised that the BMW has an engine with the same displacement, pushing a much heavier car, and still has a significantly higher highway fuel economy rating. But like others have said, real-world mileage can vary. Maybe the ratings are misleading.

Forget the price of the car? You missed my whole point, which was that technology costs money. If Subaru wanted to put millions into R&D'ing a 40mpg boxer engine that made 300hp they could certainly do it, but it would cost significantly more, and the BRZ would go from a $25k car to a $50k car, or worse. So no, you can't compare a BMW 2.0L to a Subaru 2.0L. There are plenty of other factors that play into it too; this is only one.