I got a Mazda 3!

[oldschooleco]

Hello everyone!

After much debate I've decided to get a 2005 mazda 3 hatchback. It is a 2.3 5 speed,(the wagon doesnt come with a 2.0 unfortunately) I don't have any mpg numbers yet but i plan on starting a log soon.

My first mods i am thinking about are tire pressure at 40psi, and a scan gauge to start. Also possibly a rear diffuser/ belly pan and grille block(s)

Future plans include a roof extension/kammback, rear wheel covers, lower the car 1.5"

Id like to see 40mpg out of it, any Mazda owners out there with any advise?

Looking forward to the conversation:thumb:

[Vman455]

This is probably the only active car forum on the internet where users wish they could have gotten a smaller engine. Congrats on the new car!

[thepunisher]

How about a warm air intake? I plan on experimenting with this soon on my Starlet by routing a new intake pipe to take air from near the exhaust manifold. I allready have a "WAI" of sorts just by removing the "CAI" but I reckon it could be warmer!

[niky]

Low hanging fruit that are easy and have no/few negatives... the rear wheel skirts, the pan and tire pressures (try 45 or more if your tires are still in good nick).

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[Fat Charlie]

Start the log at your next fill up. Worry about bragging rights later, but measurement has to start as soon as possible.

[Daox]

Congrats on the new wheels. I agree with Fat Charlie, start logging asap. More info is always better and it'll help the sooner you have it available.

[dkunitz]

Welcome to the MZ3--I picked my 2006 version (fuel log) because I felt that it had such better build quality than the other used hatchbacks I looked at and because it only had 63K miles when I bought it in 2014 and I wanted to get back into a manual transmission.

I could get mid- to upper-30s MPG on the highway just by running sidewall max PSI and using DWL, targeting the PSL. DWL is easiest with instrumentation--I have a ScanGuage Velcroed to the top of the steering column so I can watch my realtime mpg to make slight throttle adjustments. I said could because I don't take road trips anymore since my in-laws moved nearby. So now it's all city.

Short trip city driving is a struggle: despite using sidewall max PSI, EOC, DFCO, never idling, DWL, DWB, timing approach to lights and traffic, short & skip shifting, route planning for lights/topography, removing all stuff from my car; I still can't reliably get over 27 MPG driving my 15 minute commute over a tank. The only idea I have is that the car isn't fully warming up.

So, to help my short trip MPGs, I think I'll need to fully block the upper grill, partially block the lower grill, add a WAI, and maybe use an engine blanket.


So, that's my current situation... Are you primarily driving city or highway miles?

[oldschooleco]

Thank you everyone for the replies, i just got a scan gauge 2 the other day.

I've driven about 60 miles averaging about 35.5 mpg with no mods. It was about 20% highway 80% around town. I know i can do better, i haven't even pumped up the tires yet. It was all throttle modulation and coasting to stops in neutral. I'm still trying to figure the best way to accelerate, but that will come in time.

Money got a little bit tighter so i can only do very cheap mods until I'm in a better spot. I plan on 45psi, partial grill block, and maybe a hot air intake.

I read somewhere that Mazdas have relatively "high" compression and that running 93 would have mpg benifits? any one have any backing to this?

[Vman455]

Originally Posted by oldschooleco

I read somewhere that Mazdas have relatively "high" compression and that running 93 would have mpg benifits? any one have any backing to this?

Not likely; higher octane would have been specified by Mazda if necessary to prevent pinging. You might see a benefit to economy if premium fuel at the particular station does not contain ethanol (and regular does), because there's actually higher energy content in a gallon of non-ethanol gasoline.

[MeteorGray]

I'm happy with my 2015 Mazda 3 with the 2.0L automatic. It has a compression ratio of 13:1 but uses regular E10.

I'm mostly on the highway with A/C running all the time. My 17,000-miles average is 42.5mpg, and I'm happy with that.

I never do any advanced ecomodder techniques such as coasting with engine off since I use the car for long highway trips and it would drive me nuts to think about driving that much, not to mention all the traffic around me. I do run with tire pressure at 40psi or above, and am a moderate driver who often runs several mph below the speed limit.

On a typical 400-mile-long trip on highways with speed limits from 55 to 75 mph, I often average about 58 mph at the end of the trip because I usually cruise a bit below the limit. Red lights and heavy traffic often cut my average speed too.

The Mazda 3 is a great little car; fun to drive, pleasing on the wallet. My lifetime cents-per-mile average fuel cost with the car is currently at 4.5 cpm. As noted, this is without trying too hard.