The AX Eco Project : 100 mpg target !

[Doni_99]

Originally Posted by HypermilerAX

...
I didn't imagine I gained that much with the mods since I did them one by one. When you change all at once, you see the difference.

Hi HypermilerAX,

I have been following up your FE figures on spritmonitor.de for a long time. Congratulation for your result.
Yes I read about the 1360ccm engine that is less reliable but the 1527ccm engine is much better.
My next car will be an AX, presently I drive a Volvo 244 with a diesel engine (2383ccm, more accurately after engine rebuilt: 2414ccm). I usualy measure 4,6L/100km on steady 80km/h. My car weight is 1360kg so I hope I will be able to reach the 2.7-2.6L with my future AX.

I estimated this figure on the base of a Hungarian used car test in which the old Citroen was compared with the new Mazda 2. The AX (1360ccm) won with 2,99L/100km. The test consisted of city, road and highway drive.

Keep us informed about your further results.
Doni_99

[HypermilerAX]

Thanks for the support. It's nice knowing so many people follow me (I also get a lot of mails).

4,6 l at 80 is pretty good for that type of car considering the size of the engine and bad Cd.
I currently drive a Peugeot 305 wagon 1.8 turbo diesel (maintenance on the AX) and I get around 4,5 l at 90.

I hope for you you can get such good figures, but you'll see it's not easy.

It's surprising a test returned only 3 l on the AX, usually car testers drive rather fast. Do you happen to have this test on a file ?

[Doni_99]

Originally Posted by HypermilerAX

It's surprising a test returned only 3 l on the AX, usually car testers drive rather fast. Do you happen to have this test on a file ?

Here is the link where you can find the test. With google translator you can easily read it in your language:

Totalcar - Tesztek - Kér itt valaki enni?

As I heard 1.4 engine consumes a bit less fuel (-0.2-3litre) than the 1.5 does.
As you will read the riporter was the driver (and not the owner) to avoid hypermiller tricks to get better fe. My 2.6L aim is for steady 80km/h.

Better and better FE!
Doni_99

[Piwoslaw]

Originally Posted by HypermilerAX

Good thing is that on these cars everything can be fixed for cheap when you do it yourself.

The good thing about these cars is that almost everything you can do yourself No specialized tools, no need to take apart half of the car to replace a lightbulb.

Originally Posted by HypermilerAX

Also, for the inspection I removed all the mods. And wow, I saw my consumption rise to 3,3 l (vs 2,8-3,0) although driving very cool like usual.
I didn't imagine I gained that much with the mods since I did them one by one. When you change all at once, you see the difference.

You know you're and ecomodder when...
... You take off all of your mods and still get great fuel consumption.

[Pandaf]

Originally Posted by Piwoslaw

You know you're and ecomodder when...
... You take off all of your mods and still get great fuel consumption.

You know you're an ecomodder when you are able to convince the technical inspectors they should try this on their cars too!!

Sorry...back on topic, like your AX project BTW. Owned an 89-er 1.1 long time ago myself, following with interest.

[HypermilerAX]

Regarding my future tires, I have made a graph showing FE as a function of different tire sizes. They range from 145 to 185 in width, 55 to 80 in height ratio and 13" to 14" in rim diameter. These are all the sizes I could mount (and that are at least as big as my current tires), not all the ones I consider to mount (I’ll try to avoid 175 and 185 for example).

y : FE in l/100 km
x : tire sizes arranged by diameter, the letter at the end in the rolling resistance class : A is best G is worst. My OEM tires are E, they are all at least as good except one (F). My current tires are on the far-right.

The FE shown is the theoretical FE at 56 mph with as only mod longer 5th gear (estimated gain of 10%). It takes into account the changes in rolling resistance, Cd (width dependent), frontal area (width and diameter dependent) and RPM.
For the Cd, I took the most optimistic figure I found in literature : +0,002 Cd for +10 mm tire width.
For RPM impact, I estimated a 7,5% FE gain for a 10% increase in diameter. While this is probably near to reality for tires that are 0-10% bigger, I imagine that for 20% bigger tires, the gain will be inferior to 15%. So FE for the biggest tires are to take with caution. I won’t be able to mount such tires anyway, I have yet to test with an old 165/70/14 tire what is the maximum I can mount. And then, I’ll make my choice considering the price too.
Also, this is only for changing the front tires. Since I have much more room for bigger tires on the front than on the rear, I’ll keep my original tires on the rear and put bigger tires on the front for lower RPM.
The graph shows that diameter seems to be the main factor in FE change. The ones that are out of the trend are tires that have either particularly bad RR or are very width.

[euromodder]

People have had very mixed results with increased tyre diameters: it doesn't always work out the way they had hoped ...

I'd take a recent, B rated tyre - the best available at the moment - no matter what size you finally chose.

[HypermilerAX]

Yes, I think that's what I'm going to do.

To keep you waiting for my future mods, I'll show you the dashboard I have mounted in my car. Originally, the car has a cheap dash with only speed, tank and an analog clock. I have mounted several more gauges taken from high-end Citroën models : revs counter, water temp, oil temp, oil level and oil pressure. The sizing and writing is the same but some adaptations had to be done to make it fit. The wiring has been completely redone. Revs counter is nice, water temp very important to monitor grill block effects, oil temp indicates when the engine is at operating temp. Oil level and pressure are not that crucial.

I forgot to take a pic of the old one but it looks like this :

And this is the new one :

[Arragonis]

Just a quick post to say very impressed and to get on the mailing list for updates. The AX is a superb eco motor.

Do you have more pics of the car itself ?

[HypermilerAX]

Originally Posted by Arragonis

Do you have more pics of the car itself ?

Right now, no. But for sure, I will post some soon.