Hi everyone. I have had a few busy years what with a baby, work and everything else. Sorry for not hanging out here. I should probably fill in everyone with how things have been since the mods. It has been nearly two years now!
I removed the rubber from the front skirts and just left the aluminium front part of the skirts, much like the compromise that the original Honda Insight did with their front wheels. Seems not to have made much difference.
In a mix of about 60-70% highway driving, I averaged about 3.7l/100km with pulse and glide. In the summer I got up to 3.3l/100km with one tank and maybe 5 3.5l/100km, in the winter several at 3.9l/100km.
Recently the clutch has started to go (from all the P&G). This has meant an end to P&G, and careful gear changes - e.g. from start to first, attempt to change in first while minimizing rpm, then accelerating, or matching rpm to gear while changing. It's winter and I get about 4.1l/100km, so it's probably around .2l/100km difference to not engine-off P&G.
My driving changed somewhat. I didn't limit myself to 80km/h after a while, as long as I had a large vehicle to follow. No real difference in fuel economy.
Although I have done some maintenance to it (regular oil and filter changes, repaired a leaking valve cover gasket), the number of km and the resale value of the car versus expense of required tyre, clutch changes, registration now about to run out, heater fan not working any more would be such that I am going to retire it.
There is also the convenience factor - basically I don't feel comfortable having the car anywhere but at work or at home off the street, because I'd fear it getting vandalized. I guess in hindsight this is a bonus as I'm now using my bike to get anywhere within an hour's biking distance. But that was also as a result of reading this forum. *
As basjoos would know, the rubbernecking gets old real fast. That means I try to leave work early on Friday so that I miss the peak hours of 18-25 year old male demographic driving around looking to impress their mates. I also try and avoid peak hours in general.
To avoid all this would be worth an extra 0.5-1.5l/100km, probably.
Now, I am the first to admit that while my modifications were functional, they did not look professional in the slightest. To make them look professional would have required more expense than I would have recouped. I maybe saved $500-750 in 2 years with the modifications. In the absence of fuel prices where they were in 2008 (or higher), I am skeptical whether a good business could have been made out of producing aerodynamic modifications for the used car market.
And if prices did get about 2008 levels for an extended period of time, car makers will start to produce properly streamlined 1-2 seat tandem automobiles like the VW 1 litre car. Either that or a business could be built to manufacture them.
So what now? Unfortunately, I will continue to need an enclosed vehicle for work purposes (I would prefer to ditch licensing costs entirely and go with a bicycle full time). I also refuse to compromise frugality for environmentalism (in practice there will not be very much compromise). I will do my best to achieve lowest yearly costs for any enclosed vehicle.
In practice this means waiting until 2nd Gen Prius comes down in price enough to be attractive to me, or there are VW 1 litre type cars at an appropriate price, or work circumstances allow eliminating the ICE from my life forever, or I build my own no-compromise VW 1 litre type car. For now, what I have calculated as being a combination of lowest cost per year and lowest cost (because I would prefer to have my money to invest), would be a 1995-97 Nissan Micra. Cheap, reputation for reliability, a supposed 4.4l/100km which I might be able to improve on. Also common enough to have a Haynes manual and a proper enthusiast community.
However, I would still attempt some subtle aerodynamic & other modifications because I know I wouldn't be able to stand the money floating away. Grille blocking, undertray, maybe mirror delete. The standard wheel covers are nearly flat anyway, so no need to modify them.
* Biking is cool. I follow the Japanese concept that a bike should be like an AK47 - cheap enough to be almost throwaway, and rugged. If you go European with expensive, nicer and built to last longer, it has to be either kept inside or it will probably be stolen. I'd rather not have to worry about that - with a cheap bike it can get stolen and is still probably cheaper than a couple year's worth of depreciation. Plus no one wants to steal an obviously cheap bike!
I have what would be known by cyclists as a "Bike Shaped Object" - a mass produced mountain bike that basically does the job. It doubles as an exercise bike because it is less efficient in getting me from A to B, so it keeps me fitter.
I probably cycle a minimum of 50km/week.
Accident avoidance is a high priority. I always wear bright (preferably reflective clothing), lights at night, and a helmet mounted mirror so that I can see what's behind me without having to turn and perhaps run into something through either not looking or changing direction unintentionally.