250mpg has all ready been achieved with CJ Urba Centurion #3. Like CJ I will keep the outside theme of the car intact with only minimal ecomodder mods. However I do have some ideas that should yield some fabulous fuel economy results.
Reduce installed power
#1. Reduce engine size. The original Centurion was equipped with the 750BB 3 cyl 17hp engine. My Centurion will have the Z482 2 cylinder which is the smallest of the Kubota Super Mini Series Engines at only 482cc. It generates 13hp @ 3600rpm. The engine weighs in at 117lbs vs the 750bb engine at 181lbs.
Weight savings with this modification is at 64lbs. My overall total weight savings goal for the car is 200lbs. So I am off to a good start with the engine selection.
#2. Reduce weight of the Engine further. Fabricate composite low profile oil pan with sump. 2-3lbs estimate saved here
#3. Fabricate Composite intake and piping. Estimated weight savings 10lbs total between intake and exhaust.
Reduce rotational mass
#3. Lighten the Flywheel. My thought is reduce it just slightly maybe 3-4lbs. That way it does not have negative effects on fuel economy yet will help the lower HP 2 cylinder engine with acceleration.
#4. Carbon fiber driveshaft. There is no good reason other than added cost not to get a carbon fiber driveshaft. They are much lighter than stock steel units. They have a smaller diameter and can with stand far greater stresses. They are also much safer than metal driveshafts. Should see a 10lb weight reduction here at minimum. Like a lighter flywheel this will enhance acceleration dramatically of the smaller Kubota 2 cylinder engine.
Even though the Z482 is only 13hp optimizing its rotational mass will allow it to perform as good if not better than the original Centurion. However the added advantage here is we have one less cylinder and 268cc less
Total weight savings with these mods should put me close to 100lbs which is half my target goal.
Once of course I get done fixing it up. I just couldn't see it sitting around collecting dust I had to buy it. For $450 minus the engine and another $1,000 roughly in shipping costs I figured it was a pretty good deal. Of course only an ecomodder would see it this way lol 
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