-   Introductions (
-   -   My New 4cyl Compact Doesn't Get Good Mileage (

Stone Axe 08-09-2008 12:02 AM

My New 4cyl Compact Doesn't Get Good Mileage
This is my introductory post.

I just bought a 2006 Suzuki Forenza Wagon with a 2.0l 4 cyl engine. It's only been a couple of days but I can tell that I'm looking at 20-22 mpg in mild city driving! My initial estimates may be colored by the fact that I've idled it a bunch, always ran the AC and only have 60 miles on it.

My previous car was a 1995 Subaru AWD Legacy 5sp with no options. It could get 20 mpg without trying. It had a monster AC that it seemed to know how to switch without significantly impacting power or mileage. It also had a surprising amount of power and torque. I assume that this power helped it overcome the AC and accelerate up to the taller gears to get this mileage.

That era Subaru AWD also had a different transaxle setup than new ones. It had a mechanical 60/40 gearing difference from rear to front and a one-way bearing on the front drive. So the front wheels spun free unless the rear wheels slipped. The new ones are like the Audi's et al and drive both ends and use electronics to split the power via 4 power-robbing torque converters - 1 for the engine (auto trans), 1 for the AWD and 1 each for the differentials. The brain box varies how much each torque converter drags hydraulicaly to distribute power.

I was stunned when I test drove a 2008 Subaru Outback (Legacy Wagon) and found that it actually got worse mileage than my 1995 version - even comparing my 13 yr old one to a 2008 one.

I have had in the past 2 really stunning fuel mileage cars and didn't know what I had when I had them.

The first was a 1979 Mercedes 300SD. It was huge, heavy, overbuilt - the engine block was enormous for a 3.0l and didn't have any material scavenging in the block mold, it looked like it was cut from an iron billet - and had a 3sp auto. The gears were widely spaced but the rear end was geared low to convert it for the American market. In Germany they don't have large city roads and our highway system in the cities - mainly ancient roads built for horses and the rare Autobahn connector. So it was designed to limp through daily city use yet be able to cruise at 100+ mph on the Autobahn. Simply changing the final drive ratio was sufficient to give heartier acceleration and allow for 55-65 mph highway cruise. It got mid 20s in the city and low 30s on the highway!

It was the first car that taught me "eco driving". It was so big and comfortable that it finally dawned on me that there was no point in racing from light to light. It could only do about 100 mph - even though it was a high-end Mercedes when new - due to its gearing, so doing 80+ mph on the highway did not suit it. I described it as my personal city bus, you get in it, take it easy, point it in the direction you wanted to go and let it gently take you there in a civilized manner. Plus it had a ginormous steering wheel that resembled a city bus. What was even more amazing was that it had 250,000 miles on it when I bought it and it maintained this mileage without any abnormal maintenance until I turned 300,000 miles on it and gave it to my nephew who took it to 350,000 miles and drove it to the junkyard!

The next car was a complete surprise. It was a 1985 Nissan Sentra 2dr with literally no options other than AC. It had power nothing, it didn't even have a radio! I was broke and unemployed when I totalled my beloved 1985 BMW 535is 5sp with leather, sunroof and power everything. It got as little as 12mpg and was lucky to break 20mpg on the highway and it needed 91 octane minimum - the owner's manual called for 93 octane! I had just been hired for a high-paying job 60 miles away and probably couldn't even qualify for a "buy here-pay here" car. I walked to an estate sale in my neighborhood and saw this pristine yet homely 1985 Nissan Sentra. I asked how much it cost, it cost $700. I expressed skepticism that any 1985 Nissan was worth more than its scrap weight - $250. The lady told me that it had one owner (her dead dad), full maintenance documentation and only 30,000 miles on it!

I swallowed my pride and went from the "ultimate driving machine" to this 2,000lb "baser than thou" sub-compact with comically tiny and narrow tires. Lo and behold this Sentra was fairly fun to drive and had mind-blowing mileage. I got 46mpg when I was doing 120 mile highway commutes. I still got 36mpg when I switched jobs and had a 20 mile city commute.

This Sentra got me thinking. How and why did it get such great mileage? It tripled the BMW's mileage and doubled the aforementioned Subaru's mileage and had spritely performance. The first thing that came to mind was that it was still a Datsun. It still had Datsun nomenclature everywhere but the trunk lid. Datsun came of age in the 70's gas crisis and this car was the final evolution of that design ethic. Apparently Nissan kept developing fuel mileage technology for several years after it was fashionable. Nissan went on to deny its Datsun heritage to the point that a 2009 Sentra only gets 25/33 mpg and weighs ~3,000 lbs.

Where did they, and everyone else go wrong? Why did my 1985 Sentra get the same kind of mileage as a Prius? Why is the Prius heralded as a technological breakthrough when Nissan could pull similar mileage numbers in 1985 without an ECM, much less a hybrid regenerative drive system? Are we all over thinking this?

Bicycle Bob 08-09-2008 12:25 AM

Weight is a big factor.

jesse.rizzo 08-09-2008 12:48 AM

Welcome to ecomodder. In answer to the last question of your post, newer cars have safety requirements that add weight, and emissions requirements that also lower efficiency. In addition, people seem to every year demand a bigger car with a bigger engine, and auto makers give them what they want, until very recently that is.

As for your current car, have you read the 100+ hypermiling tips. The easiest biggest change you can make to your car is how you drive it.

RH77 08-09-2008 01:51 PM

Welcome to EM...

The Suzuki likely has an cast-iron block, which can add to the weight of the wagon (which the Sube probably didn't have). It's a cost-saving technique. I rented a Forezna Sedan one humid summer months in Florida. It had a tough time keeping things cool and really robbed power -- that may be another factor in reducing FE.

What kind of driving do you do? Average top speeds on highways, terrain, etc?

Plus, the gearing is probably setup for additional performance per "U.S. Standards".

The wagon will likely be very rewarding for its utility. Check out the advice on the 104+ tips page and given them a try.

Best FE to ya :thumbup:


akcapeco 08-10-2008 05:10 PM

The Forenza and Reno are GM Daewoo (aka GMDAT) products and like so many Korean vehicles, are often derided for being at the bottom of their respective categories.

That said, note that there are several Aveo (also a GMDAT product) owners in the EM Garage who manage to get very, very respectable numbers from those cars.

You are the exact kind of driver who will benefit from the techniques covered on this site... I suspect you will do very well.

Start by keeping accurate records, and skip the seat of your pants forecasting -- you can't really tell anything after two days of owning the car.

RH77 08-11-2008 02:35 AM

I just drove a new Sentra and here's a few aspects in brief:

The CVT is great for City and Suburban driving. Highway speeds, headwinds, and A/C really work the 2.0L to the point of attaining just under 30 MPG. City is close to 33 or so.

Further, the suspension is terrible. It feels like a boat in the water: very tipsy feeling (each corner compresses in a marshmallow-type reaction). Oddly, ride quality is harsh. They really need to work on this. Turning the wheel back and forth in a parking lot, for example, reacts like a 1982 Oldsmobile -- abrupt wheel turn and rock-and-roll.

The squared-off edges can't help Cd either. The interior is good, with the driving position comfortable. The 2.0L seems to struggle with the CVT. Too bad a 1.8 isn't available in manual-only as a base model.


three6t 01-23-2013 10:48 AM

Forenza (Optra) is Horrible as far as Eco is concerned, else it is a fun to drive vehicle, I get 23mpg in city and about 32mpg on highway, though it is far less, i wonder if i could improve it upto 20-25% by learning hypermiling it is then a car to keep, or else i would like to dump it

brucepick 01-24-2013 08:35 PM

Haven't seen the OP in this thread since last August but anyway...

I just looked up the '06 Forenza on the EPA's fuel economy site. Stone Axe reported getting 20-22 mpg in city driving.

EPA estimates are 19 City, 22 combined, and 27 Highway mpg. So even with A/C and frequent idling, he was doing better than EPA back in August. Of course that doesn't increase his actual mpg. He was hoping for better.

Wagons will nearly always have a reduced mpg vs sedans/coupes due to the poorer aerodynamics of the boxy wagon shape. The '06 sedan version was rated 28 mpg highway with the other ratings being the same.

niky 01-24-2013 09:18 PM

The smaller engine-transmission combos in the Forenzas were garbage when they were released here (as the Chevrolet Optra). There were a number of reflashes applied to the vehicle, and even the odd ECU failure, but most people couldn't get much economy out of them.

27 mpg EPA out of a four banger on the highway is absolutely wretched.

RH77 02-07-2013 02:40 AM

2013 Mazda2 Touring 4AT Quick Review
Another update to a newer vehicle rented...

Compared to vehicles availabe 7-8 years ago when we were asking for this type of vehicle, we can register a huge improvement. Aero, FE, comfort, and some vehicles in the class with near-luxury level appointments, appeal to a broader range of buyers where "small doesn't sacrifice content". But, as we'll see, some vehicles here may be better suited for city / ex-burban operation.

2013 Mazda Mazda2 5-Door
Touring Trim Level (upgrade from Sport)
1.5L DOHC I-4 with VVT (intake)
100hp@6000 RPM
98lb-ft tq@4000 RPM
4-Speed Automatic
EPA FE: 28/34

New @ 184 miles at journey start
70 mph speed to beat oncoming Winter Storm on Day-1, 75 mph Day-2 to Airport
Strong headwinds: Day 1 (night) 15-20 mph; Day 2 (late morning) 20-30mph (MesoWest Station Data: Reference ~11:00-Noon)
Cold temps: Range= 24F dropping to 12F
Payload: Me, Computer Bag, and Suitcase (and I've lost 35lbs compared to previous tests).

Day 1: Kansas City Intl Airport to Sioux City, IA
Day 2: Sioux City, IA to Sioux Falls Regional Airport, SD
Miles: ~340
Tank 2 most accurate due to own fillup at Omaha, NE (yet similar to Tank-1)
FE = 23.4 (double checked) -- noted consumption was heavy through dash readings of FE-Avg, FE-Instant, and the dropping fuel gauge.

I was really shocked at the FE result, even with my non-Ecomodder-like driving. The engine and transmission seemed ill-suited for this cold and windy highway task. Granted it had not been "broken-in" yet, but still 10 mpg off of the mark is significant. The cruise control was used extensively, which was noted to deviate +/- 5mph on hills.

The wall of air and rolling terrain proved confusing for the transmission ECU. At one point, it was stuck in 3rd gear for several minutes, buzzing at 5000 RPM after a hill-climb levelled. With the radio's USB/i-Device connection, noises were easily drowned out. It took a glance at the tach to realize that it was time to trick it to shift.

The driving position is very comfortable and roomy. A very simple, yet feature-laden dash has some small buttons and confusing menus, but does the job. The sporty nature of the suspension and refined electric power steering offered stability in the wind, and a fun-to-drive appeal in turns. As with most 5-doors of this size, you have to take your pick between cargo or rear seat passengers.

Was this a fair test? Maybe not, but it gave some insight into Ford's "B3" platform. A month or so ago, I rented the Mazda's counterpart, a 1.6L Ford Fiesta SES 5-door Auto (pleasantly loaded with lots of extras) and achieved 34 mpg at simiar speeds. The Mazda is less expensive, not as complex (5-door is only offered), and looks more subtle with smooth lines. Fiesta is also available in sedan form, with it's lineup more aggressively styled with many more options in which to choose. The SYNC system offers a voice-operated (and steering-wheel control) link to your USB connected device for stored music, app execution, and navigation.

The FE formula to the Fiesta is slightly more power from a dual VVT DOHC plant, and a dual, dry-clutch 6-speed automatic dubbed "Powershift" -- since there is no torque converter, efficiency is increased, provides a direct connection of torque from engine-to-wheels, and places the driveline in neutral when stopped. It isn't really a smooth operator and has had some quirks/issues in the Focus, but it's new technology and intriguing to find in a sub-compact.

So, in the Mazda2 deserves a second chance -- but in the meantime, I'll take the Fiesta 5-door in the sub-compact arena.

Happy EcoDriving,


mechman600 02-07-2013 09:52 AM

All good advice. But your Sentra got the same mileage as a new Prius? I really really don't think so:

Bear32LB 02-07-2013 12:15 PM


Originally Posted by jesse.rizzo (Post 52215)
Welcome to ecomodder. In answer to the last question of your post, newer cars have safety requirements that add weight, and emissions requirements that also lower efficiency. In addition, people seem to every year demand a bigger car with a bigger engine, and auto makers give them what they want, until very recently that is.

As for your current car, have you read the 100+ hypermiling tips. The easiest biggest change you can make to your car is how you drive it.

I haven't seen the numbers so forgive me if I am completely wrong, but does it make sense to reduce mileage to cut emissions? If cutting emissions results in more fuel usage, isn't that counter productive?

Now the increase in weight might claim the lion's share of the reduction in fuel mileage and the emission controls effect on fuel mileage is much smaller than the benefit. I don't know.

It would be interesting to see how much emission controls hurt, if any, fuel mileage.

niky 02-08-2013 05:15 AM


Originally Posted by RH77 (Post 355289)
So, in the Mazda2 deserves a second chance -- but in the meantime, I'll take the Fiesta 5-door in the sub-compact arena.

Happy EcoDriving,


The Mazda2 really isn't built for high speed cruising. At 70 mph, the engine is literally screaming.

Love that little car. I've always managed to have an interesting mountain road trip on schedule whenever I've had one. Not on purpose, but by happy coincidence. In traffic, the economy is actually pretty good.

But the Fiesta is smashing on the highway. At least within the limitations of the six speed auto. I wish 6th gear were just a tiny bit longer, and the lack of a manual option is pretty sad.

rmay635703 02-08-2013 12:06 PM

Nothing like resurrecting the dead to beat a dead horse

All times are GMT -4. The time now is 01:37 PM.

Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright