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Owner: suspectnumber961
Elroy: 2003 Ford Focus ZX3 w/Zetec DOHC engine
Displacement: 2 L
Fuel type: gasoline
Transmission: automatic
Curb weight: 2551 lbs
Coefficient of drag: 0.36
Frontal area: 26.3 sq.ft.
Instrumentation: ScanGauge
Description: Car had 104K on it when bought...still getting an mpg baseline. Looks like 27.5 mpg might be it.

My evolving "theory" on this car is that it is typical of car companies reacting to legislation/EPA in this time period....very clean exhaust...not so much attention paid to actually using the gas in the engine to power the car? So with this engine...upping the combustion efficiency....among other the way to go?

According to the sticker under the hood...this car is both a PZEV and a ULEV.
Build Thread:
Current Mods: Driving so engine does not rev much above 2100 rpms....doable in most situations.

*Have since modified driving to allow maintaining ~2300 to 2700 rpm up to 40-45 mph where the car shifts into OD...then feathering the throttle (17-18 TPS if possible)...IF I expect to drive at least 1 mile before the next stop or turn. This "should" be more efficient than accelerating at 2100 rpm considering the BSFC chart.

*BSFC chart...vertical line lower left is typical CRUISING speed RPM vs LOD/torque values....middle vertical line is RPM vs LOD/torque values when accelerating at ~ 2100 RPM...oval represents RPM vs LOD/torque values when accelerating at ~ 32 TPS. Shows that TPS at 32 to maybe 35-36 (up to 3000 RPM) is more efficient (most efficient = 245 center area).

Throttle resolution mod helps in maintaining 17-18 TPS at 25-35 mph when possible.

Also trying to get off the gas before stop signs so that I hit the brakes between 30 and 35 mph (now 25 mph if possible) from a 45-50 mph cruise. For curves trying to avoid brakes when possible. Willing to go as low as 5 mph at stoplights. ;-)

Car is capable of low 40s MPG on a straight level highway.


Working on alignment...changing out fluids..tune up...and so on.

Installed a Scangauge....using avg mpg...mpg...TPS...fWT. Extra info is useful. No codes showing.

Currently using Techron fuel system cleaner and seeing a 16% mpg gain with 5.3 oz / 10 G after last fill. 2 oz / 10 G works as well? Also new fuel filter...old one not clogged. Fuel magnets.

Running tires at 38 PSI Frt-34 PSI Rr (34 door sticker...44 Max PSI)...a compromise between mpg...handling...tire wear and ride.

New Autolite double plat plugs/Kiker wires. Likely saw a 13% gain with these if Techron use/new plugs are discounted. Have no AM radio interference and see no CELs. Might pay for themselves in 8-9 months with current gas prices.

4 wheel toe alignment set close to zero toe. Camber issues resolved with camber plates in rear and rubber donuts all around?

Flushed auto trans with synth ATF and added Motorsilk additive.

Warm air intake..~20-30F above ambient when warmed up...> removed resonator on airbox to allow freer air intake from engine compartment....temp gain is down to around 15F over ambient


Air dam...REMOVED

Front belly pan

Upper grill block

2 new LRR tires on front...Kumho Ecowing

Motorsilk additives...engine and fuel

Throttle resolution allow more control of throttle right off of idle

Radiator covered using cardboard in front of it...around 5/8s area covered..WINTER only

New t-belt/idler/tensioner...serp belt/idler/tensioner...waterpump

Added indicator LED to show when cooling fan is running.

cone filter added

Motorcraft copper core plugs installed

Planned Mods: Whatever I think might many little time...

* LRR tires...2 more

* heated fuel

* underdrive pulley

* rear fender skirt?

* smaller mirrors?

* will be looking for a big granny garage sale this summer...will get me a big granny dress and a gray I can blend in as I drive. This is so people won't drive up behind me and think...I'll bet he's drunk!...they'll just see me and think...boy that's one big granny...and with a beard!


More recently I have had less interest in MPG issues...though I still have most mods and still use the Scangauge. Upped my typical cruising speed from 40-45-50 to 45-55. Using AC more during this hot summer. Might be buying another car next year.
Official Fuel Economy Ratings
EPA city 22 mpg(US)
EPA highway 28 mpg(US)
EPA combined 24 mpg(US)

Actual Fuel Economy Performance
Lifetime 33.34 mpg(US)
Last 3 tanks 32.92 mpg(US)
90 days 32.89 mpg(US)
View Fuel Log
Last updated: Aug 10, 2016

(Created: 2011-02-25 12:23:19 / Modified: 2016-09-06 08:00:53)

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