The AX Eco Project : 100 mpg target !

[Rubberduck]

Hehe Hypermiler Ax , we will see .
i ve seen today at Spritmonitor your 2,77 Liters
Very good but must drive relative Slowly .
yeah i have with my Shoebox(My AX ) my own 100mpg Project , there are Many Ideas , but need Time to realize it . I think , the Project is Possible with Only Diesel Use , for more we need some "Miracles"
but not unusual .
best regards Sascha

[HypermilerAX]

Yes, I always write my cruise speed in the notes (70/75 this time). My goal is to get under 3 l average, to reach it I have to drive at 2,8 l during 12.000 km. But after that, the aim of the mods is to drive faster and still be under 3 l.

[AndrzejM]

Originally Posted by HypermilerAX

Yes, I always write my cruise speed in the notes (70/75 this time). My goal is to get under 3 l average, to reach it I have to drive at 2,8 l during 12.000 km. But after that, the aim of the mods is to drive faster and still be under 3 l.

I like it The attitude I mean

My goal is to have an average under 4 liters/100km. For now I have 4.3l/100km lifetime average. So I would need to keep average 3.8 for over 21 thousands km to have lifetime average 4.0l/100km So in 1.5 year maybe I'll get there Or 3.7l/100km for 14tkm

[Rubberduck]

the last 2 days i have driven a Tour most Autobahn , 200 Kilo Load , tempo 110 . the Box sucked 3,8 liters . yesterday evening filled up the Tank , then 350 Kilometers Autobahn at Tempo 90 , but the Rain was Horrible . I must learn to get the Pedal softer i have programmed my Navi to warn me if i drive faster as 100 Km/h . i have al little trouble with the Gearbox , i think it´s breaking if i take off the gear for let the car roll . Tomorrow will begin the Modifications , then i make a own thread about it here .

[HypermilerAX]

8.000 km with the new gear and it works great so far. The results are good, I've never exceeding 3 l/100 km although driving sometimes a bit faster or with traffic jam. The gain is about 7,5% but I still have to calibrate accurately my flowmeter to measure it. The problem is that the calibration factors of the 2 flowmeters are not the same strangely. The flow was counting down with the same factors, I'll do the bucket test for the return line and then calibrate the supply line according to volume at gas station over several fillups. 7,5% is about 60% of the gearing change (12,7%) which is what I expected.

Performance in 5th gear is of course worse. I did a max speed test and recorded the data on a GPS (attached file). The graph shows speed, altitude (left scale) and grade (right scale). The red line is 0% grade. It's a good road to test max speed because it's reached quicker with a downhill before a flat part. The max speed is averaged between the 2 marks.
Average speed : 144,54 km/h
Average grade : -0,23%
Air density : 1,223
Wind : <5 km/h tailwind
Calculated max speed with 0% grade and 1,204 density is 143,5 km/h at 3420 rpm (32,6 hp).

Another thing is that the gearing is bigger than expected because of the tire circumference. I always took the theoretical figure which is smaller than measured.
1710 mm for a half-used 155/70 R13 (approx. 1740 for a new one) which puts my 5th gear exactly at 42 km/h per 1000 rpm.

I mounted the 145/80 R14 tires (with inner tubes because of poor sealing). They are 1870 mm big which makes an expected 7,4% increase. I tested them yesterday about 20 km and it's not that great:
-They are not well balanced, the car shakes pretty bad from 105 km/h on.
-Bad cornering stability maybe due to the high 80 ratio.
-Gearing might me too big. I have now nearly 46 km/h per 1000 rpm, even though I coundn't test the max speed due to the shaking, I had a hard time reaching 120 km/h.
I'll test them on my daily commute and the conditions to keep them is to be able to pass all "hills" (which are never steeper than 4%) in 5th gear and of course to have better FE.

[renault_megane_dci]

a taller wheel is often an heavier wheel and if your driving is mostly under 50mph, I wonder if it wouldn't have an adverse effect than what was looked for in the first place ...

[HypermilerAX]

Those were junk tires anyway, maybe the Ecopias would have done good but I'm going to stick with 13" for now. My rear tires don't have much left so I'll keep them for the inspection. I'll put the front tires on the rear and mount on the front the 155/80 R13 I just bought (what Piwoslaw recommended me in the first place ). They are Yokohama Bluearth, one of the best for 13" as regards efficiency.
My last tank is good : 2,78 l/100 km for 82-84 km/h cruise speed. No front wiper and more EOC than usual (for 500 m idling). I also began to bump start to save the starting motor and the battery. It's probably my best MPG/speed ratio tank. I was driving only 75 km/h when I lastly got 2,77 l/100 km.

[renault_megane_dci]

You are doing good buddy !

[HypermilerAX]

The new tires are good, they roll very well and are inflatable up to 51 psi. 5th gear is now 44,7 km/h at 1000 rpm, which is enough (future mods will reduce engine load anyway). Last tank 2,87 l/100 km while driving faster (20% 80k, 50% 90k and 30% 100k). I even put more diesel than usual (I stop at the first click) because I was surprised of the low consumption and thought I had to put more... but no, it clicked again and again. So I'm more around 2,80 l/100 km.
I'm currently working on some wheel covers made of aluminium sheet. I made them bigger than the rim for aero reasons (to reduce the effect of the high C-shaped sidewalls of the tire) as well as for aesthetics. But I'll have to pay attention that the (grinded to be less sharp) edge of the disc won't cut the sidewall of the tire during deformation. Maybe some tape to smoothen the edge will do it.
I'm also working on the wheel skirts. The pic is not definitive at all, I'm adjusting the shape.

[Jyden]

Looks good.