2000 Focus ZX3 - The SLOcus

[redorchestra]

Originally Posted by LocoJason

"Adding a shallow, 2°
diffuser under the
rear bumper
reduced CD by a
further 6%"

No picture of this diffuser though? For a whopping 6% change, I would think it would be shown.

and that was a FURTHER 6%, so a total of 8.4% for box cavity and diffuser.
I think it is worth a try for a 2000km trip. I just hope it will stay on with suction cups and magnets.

[euromodder]

Originally Posted by LocoJason

the car would actually pay for itself in 3 years vs my previous commuter vehicle. Win-Win.

That's the way to do it.

For many years I had been into performance cars

You're not the only one around here - far from it

I thought "slower is better, right"?

Not necessarily, as you've found out.
Depending on engine management and gearing, there's a speed where the engine won't pull off the good MPGs anymore, or will only do so under very favorable conditions.

If I drop down below 1750 (max torque on the turbo diesel) in steady driving, mileage drops down with it - unless the road is dead flat and I'm coming down from a higher speed.
But a very minor incline will make the fuel consumption jump though.

At highway / high-drag speeds, 1750 rpm in 5th is around 85 kph / 53mph.
Dropping below that, the mileage drops off significantly - like 10-15% less around 80 kph .

The downside of fast rising torque curves, is that you also fall off like a brick when going the other way

I have not tested slower and I still wonder at what speed the aerodynamic drag has reduced enough to offset the lower efficiency of the engine and actually deliver an increase in economy?

For me, at idle in 3rd or 4th !

Drag is so low, the engine can pull it off with record mileage - but the slightest increase in loading will result in bad mileage, even climbing a speedbump can kill the fun.

So that leaves me with aero mods and rolling resistance to focus on...

There's a lot to be gained from modding your driving style as well.

Basically, using only the power you need to get you to the next corner / light / stop sign at appropriate speeds - and not much more.

Are you already using coasting in neutral (or even with the engine off ) ?

[LocoJason]

One thing I forgot to mention earlier is that for the first-gen focus (US 2000-2004) the sedan and wagon both have lower coefficient of drag than the 3/5door. The information I found may be wrong, as I see differing numbers all over the internet for some reason:
Sedan:
cD: 0.31
Frontal Area(est): 21.97 sq.ft.

ZX3
cD: 0.36
Frontal Area(est): 21.97 sq.ft

Wagon:
cD: 0.30
Frontal Area(est): 22.24 sq.ft.

Considering they all have the same front end and doors/mirrors, the only difference is the rear. I fail to understand why the wagon is that much better when the roof taper in the rear is minimal. I'm sure I'll spot one in a parking lot some day, make sure nobody is looking and then pull out the tape measure and my camera...

Originally Posted by UltArc

Very cool. What are your other vehicles? I am interested in seeing your under panels, I am very interested in beginning that project after the winter.

Besides the Slocus, I have the following:
1998 Pontiac Grand Prix GTP - dyno 305whp - wife's car.
1984 Nissan 300ZX Turbo - dyno 453rwhp - track/fun car.
1988 Toyota Celica Turbo Alltrac (GTFour) - est. 200awhp - winter beater/rallyX car.

The underpanels I made are just covering the front of the nose, in front of the engine. Some sheets of black coroplast cut to fit. Many cars have factory-installed panels in that location... I still wonder why mine didn't.

[LocoJason]

Originally Posted by euromodder

...

There's a lot to be gained from modding your driving style as well.

Basically, using only the power you need to get you to the next corner / light / stop sign at appropriate speeds - and not much more.

Are you already using coasting in neutral (or even with the engine off ) ?

I already drive conservatively enough that I piss people off. I coast _A LOT_ when I drive in town. I don't accelerate up to red lights, and that alone seems to be enough to get some people's panties in a bunch. Why everyone is in such a big hurry when they drive in town is beyond me; the lights will determine how fast you're going to get there. If people are in such a big hurry, why don't we see people running through the grocery store all the time?

Your comments about load sound like the exact same thing I've observed. With the lower engine speed at a lower vehicle speed, the engine is actually less efficient at making the required power to maintain speed. Even though that power requirement may be slightly lower, the loss in efficiency trumps the reduction in aerodynamic drag.

[LocoJason]

Not sure where else ot post this but one more question:

Is the Focus not a very popular Ecomodder car?

I don't see a lot of people, or posts on here when I search. Yet I see TONS of them on the road.

[redorchestra]

I think the focus is more popular with the ricer/racer type crowd. They are quick little things and have a ton of aftermarket add-ons

[UltArc]

Originally Posted by redorchestra

I think the focus is more popular with the ricer/racer type crowd. They are quick little things and have a ton of aftermarket add-ons

In my neck of the woods, they are more economy car/race ricer wanna bes. Usually it's girls 17-22, or they are boys 17-28 with all the junk on them. I wonder how many pounds of boost that flame on the side adds. They are pretty cheap, and easy to work on, and get parts. It seems like an above avergae eco car, not quite a Metro, but if you want something newer and moreoptions. I mean dropping my cd from .38 to >.34 had made a huge difference.

But then again, you might worry like me that your chin splitter might be shoveling for you come winter time.

EDIT: I guess I thought this and didn't write it, but with all the parts and junk, surely you can find a decent body kit to lower your cd, ground clearance, side height, so on. I know most of them are ugly and gaudy, but they do make more modest ones, and without the bumble bee fart can, I couldn't see much judgement as a ra/icer.

[Allch Chcar]

Originally Posted by LocoJason

One thing I forgot to mention earlier is that for the first-gen focus (US 2000-2004) the sedan and wagon both have lower coefficient of drag than the 3/5door. The information I found may be wrong, as I see differing numbers all over the internet for some reason:
Sedan:
cD: 0.31
Frontal Area(est): 21.97 sq.ft.

ZX3
cD: 0.36
Frontal Area(est): 21.97 sq.ft

Wagon:
cD: 0.30
Frontal Area(est): 22.24 sq.ft.

Considering they all have the same front end and doors/mirrors, the only difference is the rear. I fail to understand why the wagon is that much better when the roof taper in the rear is minimal. I'm sure I'll spot one in a parking lot some day, make sure nobody is looking and then pull out the tape measure and my camera...

I'm curious where you got those numbers? The numbers I remember for the ZX3 are .36 and .32 for the ZX4. But I never found the official numbers.

The back is the only difference as far as the aerodynamics. I had a discussion on Focaljet about this exact same thing.

The engine in the ZX3 and the ZTS for the First gen is the DOHC Zetec. It's the higher output engine so not only is the torque peak higher RPM the gearing is shorter. It doesn't drop valves like the SOHC split port, but the MPG is worse.

BTW, that's a nice selection of cars. Grand prix, heh.

[buzz_42]

Originally Posted by LocoJason

I've thought about some of the things that could be done to further improve fuel economy. Engine mods like a custom intake cam, adjustable cam gears, etc. were all major turn-offs to me. Why? This car can hardly get out of its own way as it is, I doubt I could tolerate driving a vehicle much slower.

So that leaves me with aero mods and rolling resistance to focus on...

Hey Jason,

Not sure if you've discovered this yet, but SCT makes a programmer for the focus. I am researching it for mine. My focus has a magnaflow exhaust and an AEM CAI.... I haven't tested it with my PLX (similar to scangauge), but I will let you know.

In the meantime, check out the link to the SCT stuffsorry about the spaces)

www . sctflash . com / products.php?PID=2&VID=391#2

[LocoJason]

I knew about the programmers, and I saw someone put up a fuel economy tune on focaljet. Looks like it was a couple years ago. The problem is the large price tag involved for a small gain. If you keep the cat (which I will) you can't run very lean at all. I can't justify spending that much money to improve maybe 6-8% or ~2-3MPG tops, because even at 20,000 miles per year it would take many years to get a return on that investment.