Real-world MPG difference between 2.0L and 2.3L Mazda3? (2004-2009)

[1337]

In the first generation (04-09) Mazda3, there were two I4 engines offered:

2.0L -- EPA MPG: 24/32 manual, 23/31 4-speed automatic
2.3L -- EPA MPG: 22/29 manual, 22/30 5-speed automatic, 21/26 4-speed automatic

I'm considering getting a used first-gen manual Mazda3, and I'd prefer to have the versatility of the hatchback. Unfortunately, the hatchback bodystyle is only available with the 2.3L, so I'm trying to weigh the tradeoffs.

Questions:

• Are the EPA figures realistic?
• In real-world driving, how much of a difference is there between the manual 2.0L and the manual 2.3L in terms of MPG?

I did a little bit of homework: I found two 2004-2009 Mazda3 entries in the Ecomodder garage that have more than a couple of fillups: a 2.0L manual getting 35.9 MPG and a 2.3L 5AT getting 29.2 MPG. I'm still interested in hearing everyone's two cents on this.

[RobertISaar]

if you want something badly enough, is the 10% difference in fuel economy(and therefore cost) really going to push you into something you don't want?

10% is a big jump in the realm of fuel economy, but not enough for me to drive something i don't want to drive compared to something i do want to drive.

[pete c]

I think if you use hypermiling techniques such as p&g, the difference is narrowed, because your pulses will be a bit shorter. Driven normally, the 2.3 will be less efficient.

In the end, I would go for the best vehicle/best deal regardless of the engine size. And if getting a hatchback is your preference, get it.

[mcrews]

Check the rear end gear ratio.
That may be the difference......And that's something you could swap uot.
Also, if you can upsize the tire, you could close that gap!

[1337]

Originally Posted by mcrews

Check the rear end gear ratio.
That may be the difference......And that's something you could swap uot.
Also, if you can upsize the tire, you could close that gap!

Good point. The 2.0L and 2.3L manuals have the same gear ratios. The final drive ratios vary slightly from year to year. In most years, the manual final drive ratio is shorter than the automatic. Only for 2004, the 2.0L has a shorter final drive ratio (3.683) than the 2.3L (4.416).

I wonder if the final drive ratio from the automatic can be swapped into the manual version.

I think the 2.3L manual's 4.105 final drive ratio could be replaced with the 2004 2.0L 3.683 final drive ratio.

Originally Posted by mcrews

Check the rear end gear ratio.

Ah, it would be awesome if the differential were at the rear end. I wish there were a reliable, fuel-efficient, underpowered, good-handling RWD wagon on the market. Sigh.

[mcrews]

SERIOUSLY, CHECK UPSIZING THE TIRES....I have done both my cars, the q45 and sportage. both gained over an inch in diameter.
you want to look at the lower base on the strut towers for clearance. i have pics in my thread on the 'ecomdding kia sportage'. you could pick up 5-7% on tires withuot a lot of work!
Then if you can play with the gears.......your miles ahead!