Why isn't the fuel economy better?

[Skywgn1]

I installed an Injen Intake and for S & G's put in a tornado setup right after the MAS. I now get 28 in town and 36 on the highway doing 80 MPH. Just enjoy the FR-S for what it is. A great car that seems to make the winding roads into a straight line. And puts that curve on your face because you're having so much fun. Customize the piss out of it and make it yours!

[draggin_az]

Originally Posted by Khalis

Oh, good. I average about 25mpg with 60/40 highway/street split. I thought there was something horribly wrong. I guess it's just the hills here.

same here

buuuuuuuuuuuuuuuut ever since i got an intake and tune, my "average" has dropped to 19 b/c i cant keep my foot out of it. the car feels so amazing i cant help but driving it like a bat out of hell.

[Subie]

I average ~32 MPG mixed driving, probably 85% highway, 15% city if I had to guess. The mileage is very good, IMO.

[fatoni]

i cant think of a n/a 2.0 with 200 hp that does better

[mact]

I'm averaging 28.5 MPG with about 50/50 hwy/city driving.


No complaints here since my other vehicle averages 19-20 MPG.

[DarkSunrise]

I actually had the same thought when I first looked into these cars. At 2750 lbs with 200 hp, shouldn't it be rated better than 22/30? Having bought the car though, my real-world mileage has been better than the EPA figures would indicate. My display indicates 30 mpg in mainly city driving. Even accounting for an optimistic read-out, that far exceeds the EPA's 22 city rating.

In my experience, NA cars tend to exceed their EPA estimates in real-world driving.

Originally Posted by fatoni

i cant think of a n/a 2.0 with 200 hp that does better

RSX Type-S -- 23/31

[kentah]

I'm curious how many other people reporting mileage are using the dash readout. I know mine is showing about 30 mpg but when I checked at my last fuel up, it was 26.4 mpg. That's not bad and I'm not driving like grandpa but I'm pretty skeptical of the person reporting 40 mpg.

If you're going to post mileage, post actual mileage not the display readout as it means very little.

[MVJ1975]

Originally Posted by DarkSunrise

RSX Type-S -- 23/31

The RSX only gets 20/28 under the new 2008 system, worse than the MT FR-S.

[rhood168]

Man idk how you guys are doing it but im getting around 18 mpg and no im still under 1000 miles so im talking it easy. Highest ive seen it go is 22. Starting to think something is wrong

[White Shadow]

Originally Posted by Turbowned

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.

Do you really think that Toyota/Subaru invested less money in R&D for this new engine than BMW did for their new 2.0 mill? Sorry, but I don't buy that. It's not like the boxer is a low-tech engine. It's very much a modern powerplant that had to go through extensive (and very expensive) R&D, just like any other new engine.

But again, I'm not concerned with the money. The fact of the matter is that I'm comparing two cars that have the same displacement, but one is about 1000 lbs heavier than the other. Is it a perfect comparison? Absolutely not. One is N/A and the other is forced induction. Still though, I wouldn't expect better fuel economy numbers out of the much heavier car, all else equal. I don't see any kind of high dollar, exotic design or materials in the BMW engine that gives it any kind of distinct advantage, do you?

As someone else suggested, it might have a lot to do with gearing. The nice thing about having a really torquey engine is that it's perfectly happy zipping along at highway speeds at a really low RPM. For that reason, cars like that BMW are geared to be at a very low RPM in top gear at highway speeds. In that regard, the BMW is very much like my Audi. I can be driving 55 mph in 6th gear and there's no need at all to downshift if I want to pass another car. It just pulls strongly even from low RPM. I think that's probably the biggest reason for the good highway fuel economy.

[fistpoint]

I've wondered this exact question myself, and even used the same BMW as my argument. I concluded that BMW is simply better at building efficient engines, but when it comes to longevity they pale in comparison to the 2.0L 4 cylinders that get slightly worse mpg.

Why does a sub 300hp Accord V6 get the same mileage as a 412hp Mustang GT V8? I'll take longevity over a couple mpg any day, but the question still remains.

[White Shadow]

Originally Posted by fatoni

i cant think of a n/a 2.0 with 200 hp that does better

That's funny....but how many cars are out there that have a naturally aspirated 2.0L engine with 200 HP? Other than the FR-S/BRZ, I can't think of any off hand.

But consider a car like the new Dodge Dart. It may not make 200 HP, but it does come with a naturally aspirated 2.0L engine and it has a fuel economy rating of 25 city 36 highway.

[fatoni]

Originally Posted by White Shadow

That's funny....but how many cars are out there that have a naturally aspirated 2.0L engine with 200 HP? Other than the FR-S/BRZ, I can't think of any off hand.

But consider a car like the new Dodge Dart. It may not make 200 HP, but it does come with a naturally aspirated 2.0L engine and it has a fuel economy rating of 25 city 36 highway.

Or any car with a 100hp/liter motor. My point isnt that it doesnt happen. Its that its not bad

[White Shadow]

Originally Posted by fistpoint

I've wondered this exact question myself, and even used the same BMW as my argument. I concluded that BMW is simply better at building efficient engines, but when it comes to longevity they pale in comparison to the 2.0L 4 cylinders that get slightly worse mpg.

Why does a sub 300hp Accord V6 get the same mileage as a 412hp Mustang GT V8? I'll take longevity over a couple mpg any day, but the question still remains.

I'm pretty sure a V6 Accord has higher EPA fuel economy numbers than a new Mustang GT.

Again, I think gearing plays a big role. And certainly the curb weight of the car....and aerodynamics certainly has something to do with it too. But that brings me back to my original thought---the FR-S is a tiny car. It weighs well under 3000 lbs, which is very light these days. I just thought it would have better fuel economy than a significantly bigger & heavier car that has an engine of similar displacement. Obviously, it's more complicated than that, so I guess I was simplifying my thoughts.

On the other hand, the MX-5 Miata is a small, lightweight car with a 2.0L engine, and it gets the same combined fuel economy ratings as the FR-S. The MX-5 doesn't make 200 HP though...