Specs vs Actual Fuel Economy for an 2002 Impreza 2.5TS

[Jimmy]

Hi All,

The specs on my 2002 Impreza 2.5 TS (manual transmission) state the
following:

11.1 liters / 100 km (City) - equivalent to 21 MPG
7.8 liters / 100 km (highway) - equivalent to 30 MPG

In theory, I should be able to do 540 KM ( 335 miles) in the city and 770 KM
(477 miles) on the highway with a 60 liter tank (15.85 US gallons).

I currently do about 480-500 KM (298 to 310 miles) with about 60% of my
driving being city driving. I can't even meet the minimum 335 miles of all
city driving.

Car has 38,000 KM so I assume it is broken in. It's my wife's car and she
shifts at about 2500 RPMs. She doesn't speed and generally cruises at 110
kph (65 mph). Does anyone have any idea as to why my actual mileage is so
different from the specs . Any clues as to what I can do to improve my
mileage (other than maintaining tire pressure at recommended levels)?

Thanks

Jim

 

[Hallan Blaggit]

If you want to match the rated fuel economy numbers, the best way to
do it is in a lab, on a test stand. you certainly can't do it in the
real world. The numbers are for comparison, from car to car, and are
generally unobtainable in the real world.

Incidentally, NRC in Ottawa had some Priuses (or would that be
Prii???)...their long term fuel economy numbers weren't a whole lot
better than an off-the-lot Echo....which raises the point of why
bother?

 

[Edward Hayes]

All my vehicles; Volvos, Saabs and now my 2000 Forester meets both the USA
EPA city/highway estimates easily. I don't know about other countries and
how they determine mileage. If nothing else it gives you a model to model
comparison. ed

 

[Jimmy]

I'm not trying to match the rated numbers. I would just like to know if
there is anything I can do to improve my car's fuel economy. Is that ok?

 

[Fuzzy Logic]

The specs on my 2002 Impreza 2.5 TS (manual transmission) state the
following:

11.1 liters / 100 km (City) - equivalent to 21 MPG
7.8 liters / 100 km (highway) - equivalent to 30 MPG

In theory, I should be able to do 540 KM ( 335 miles) in the city and
770 KM (477 miles) on the highway with a 60 liter tank (15.85 US
gallons).

I currently do about 480-500 KM (298 to 310 miles) with about 60% of my
driving being city driving. I can't even meet the minimum 335 miles of
all city driving.

Car has 38,000 KM so I assume it is broken in. It's my wife's car and
she shifts at about 2500 RPMs. She doesn't speed and generally cruises
at 110 kph (65 mph). Does anyone have any idea as to why my actual
mileage is so different from the specs . Any clues as to what I can do
to improve my mileage (other than maintaining tire pressure at
recommended levels)?

I have an '03 2.5 TS with manual transmission and regularily get over 400KM
on ~45 litres (a typical fill up for me). This is all city driving. I tend
to shift between 3000-4000RPM. I've only got 12,000KM on my vehicle. Do you
spend a lot of time just sitting in traffic? My commute to work is the
opposite of most so I rarely spend much time idling. If not maybe you've got
a bad oxygen sensor?

 

[powertrain]

Hi All,

The specs on my 2002 Impreza 2.5 TS (manual transmission) state the
following:

11.1 liters / 100 km (City) - equivalent to 21 MPG
7.8 liters / 100 km (highway) - equivalent to 30 MPG

In theory, I should be able to do 540 KM ( 335 miles) in the city and
770 KM (477 miles) on the highway with a 60 liter tank (15.85 US
gallons).

I currently do about 480-500 KM (298 to 310 miles) with about 60% of
my driving being city driving. I can't even meet the minimum 335
miles of all city driving.

Car has 38,000 KM so I assume it is broken in. It's my wife's car
and she shifts at about 2500 RPMs. She doesn't speed and generally
cruises at 110 kph (65 mph). Does anyone have any idea as to why my
actual mileage is so different from the specs . Any clues as to what
I can do to improve my mileage (other than maintaining tire pressure
at recommended levels)?

I switched to a higher octane gas. I found that I get much more out of a
tankful than with regular gas, and with much better performance. Of
course doing so you have to pay more at the pump so overall I'm probably
not saving much, if anything.

 

[Larry Van Wormer]

Hi All,

The specs on my 2002 Impreza 2.5 TS (manual transmission) state the
following:

11.1 liters / 100 km (City) - equivalent to 21 MPG
7.8 liters / 100 km (highway) - equivalent to 30 MPG

In theory, I should be able to do 540 KM ( 335 miles) in the city and 770 KM
(477 miles) on the highway with a 60 liter tank (15.85 US gallons).

I currently do about 480-500 KM (298 to 310 miles) with about 60% of my
driving being city driving. I can't even meet the minimum 335 miles of all
city driving.

Car has 38,000 KM so I assume it is broken in. It's my wife's car and she
shifts at about 2500 RPMs. She doesn't speed and generally cruises at 110
kph (65 mph). Does anyone have any idea as to why my actual mileage is so
different from the specs .

One reason is the higher cruise speed. I think the highway rating is for
80 kph. 110 will suck quite a bit more fuel.

Another is cold startup, the car uses quite a bit more fuel until it's
warmed up, and that can make quite a difference in city driving, which
is typically short hops.

I have an MY02 TS, and expect between 550 and 580 km per tank, normally
I fill it when I need about 50-52 litres litres

I have occasionally seen as high as 34 mpg (Imperial gallon that is...)
which is fairly close to the rating for highway. I believe I could see
38 mpg if I ever stayed at 80 kph... So, I don't think the ratings are
unachievable, just not likely with normal driving practices.

Larry Van Wormer

 

[hippo]

Agree with previous few posts. Short/cold trips will kill fuel economy.
Other than that: try running pressures around 35psi; keep services up to
schedule and filters changed regularly; Don't run a/c all the time. Apart
from that, it's usually down to how each individual drives - unless
there's a fault with the particular car somewhere. Cheers

 

[Jimmy]

My '98 Acura Integra also comes close (but not quite) to the rated mileage.
So this is why I am wondering why the 2.5TS is not as performant.

 

[Jimmy]

We've recently moved to the suburbs and I have noticed an small improvement. Can you give a little more detail on the oxygen sensor and its impact on mileage?

Jim

 

[Jimmy]

I guess the cold weather is the main issue. 35 psi for all four tires?

 

[Fuzzy Logic]

We've recently moved to the suburbs and I have noticed an small
improvement. Can you give a little more detail on the oxygen sensor and
its impact on mileage?

Here is a bit of info:

http://www.mr2.com/TEXT/O2_Sensor.html

 

[Business]

I have exceeded the rated milage on the road in real driving.
I set the snooze control at 80 k's in the country with little traffic.
It can be done
65 mph will not get you high milage 45 to 50 will
speed is your trade off to arriving a few minutes later

If you want to match the rated fuel economy numbers, the best way to
do it is in a lab, on a test stand. you certainly can't do it in the
real world. The numbers are for comparison, from car to car, and are
generally unobtainable in the real world.

Incidentally, NRC in Ottawa had some Priuses (or would that be
Prii???)...their long term fuel economy numbers weren't a whole lot
better than an off-the-lot Echo....which raises the point of why
bother?

H

 

[Chill]

Hi All,

The specs on my 2002 Impreza 2.5 TS (manual transmission) state the
following:

11.1 liters / 100 km (City) - equivalent to 21 MPG
7.8 liters / 100 km (highway) - equivalent to 30 MPG

In theory, I should be able to do 540 KM ( 335 miles) in the city and 770
KM
(477 miles) on the highway with a 60 liter tank (15.85 US gallons).

Jim, just a thought:- is your math based on the assumption that you're using
all 60L of gas? Obviously you won't run your tank dry, and it's possible
you're not taking into account the last 5 or so L left in the tank when you
fill up and take note of your mileage.
FWIW, I have a 2004 2.5 TS 5speed wagon and get about 520 or so km before I
feel the little orange light has been on long enough. I think it's designed
to come on with about 10L left
My driving is about a 50/50 mix of hwy/town, and I don't consciously try to
minimise consumption.
Just my 2c worth,
Chris

 

[hippo]

Best other way of getting accurate figures is fill up at the same
station/pump each time and check actual litres you put in against mileage
- assume that's how youre already doing it. My 99 Outback AT is doing
slightly better than that so I'd expect a lighter car to better it
everything else being equal. Cheers

 

[Jimmy]

You bring up a good point.

I'm usually left with 5L to 8L in the tank when I refuel. If I assume 50/50
(city/hwy) driving, then I should do 650km on a full 60L tank or 590km with
55L of fuel. Since I do about 500km, maybe playing around with the tire
pressure and cruising at 80kph might do the trick.

I'll keep better records for the next few weeks to see.

Thanks for the input.

 

[A Doc]

i got 38 mpg in my fairly modified 94 impreza 5 speed.
go figure

alex