It really is tough to add lightness. I know this from first hand experience.
The Smart Car is mostly underpowered. It is fine for what it is designed for, putt putting around the suburbs, but that is not what I was looking for… I wanted a car that could be driven at 8/10s at legal speeds.
I had two options. More power from the motor, or help the motor work less.
Most people go the first route and add a turbo to the motor. The motor is very strong, it can take the extra boost from the turbo, but drivability then becomes an issue.
The Smart car motor is 3 cylinder, 0.9 liter. It is the heart of a humming bird. In other words, it revs like crazy and loves doing that. Adding a turbo that only kicks in a higher revs is like feeding Red Bull to a humming bird. It works, but at the end of the day, it makes no difference. The thing is still spinning like nuts. Getting it spinning is still takes the exact same amount of time and power.
The other problem with adding a turbo is that doing that makes zero difference to helping the car go around corners.
It also makes zero difference to stopping the car…..
Both those factors, corners and stopping can be helped hugely by adding lightness.
So that’s what we did.
We have removed the roof, the doors and changed the stock bucket seats for lightweight moulded seats.
Sounds like a lot right?
No.
Sadly, it is only around 160 pounds or 72 kg’s lighter than where I started.
I know because I have weighed the car on the local feed store grain scales.
(BTW, FWIW, the total weight is now 1780 pounds or 897 kg’s).
There is very little left to remove. We joked about pulling the carpet.
The windshield is an obvious one, but doing that in California means I have to change its registration to a motorbike and wear a full face helmet every time I drive it.
When I have to do the clutch, we have to remove the motor, at that time, we will remove the air conditioner compressor, evap radiator and hoses…. After that, I just don’t see anything left to remove….
But, even so, the good news is that even after just dropping those ‘few’ pounds it has made a MASSIVE difference to the all round performance of the car.
It accelerates much stronger, it can turn on a dime (I might even know that it can turn 180 degrees while staying inside a small country lane…. or I might not – Sush Matt W) and it stops beautifully (most of the time – sush Terry).
So, all of that was a very long lead in to this article.
http://www.cnet.com/roadshow/news/making-a-car-lighter-more-difficult-than-you-might-think/
One might operate under the belief that making a vehicle lighter is easy — just take some stuff out, or use a new metal engineered for lightness. But there are a whole host of factors standing in the way.
While the base body weight of a vehicle has dropped markedly over decades, desire for creature comforts and additional safety equipment has resulted in an increase in curb weight over the last 30 years, even though we’re using fewer heavy materials (like iron) than ever before.
This isn’t even an easy topic to crack, as there are no convenient averages across the entire industry. With every car radically different than the next, despite sharing some or many similar parts, the study concludes “there is no single cost estimate (cost per pound) for lightweighting.” Thus, every company attempting to do so is taking a risk that it can’t necessarily grasp fully.
So, it’s not as easy as Colin Chapman’s “simplify, then add lightness” quote would have us believe. In fact, adding lightness is anything but simple.
That last sentence is the prod for this blog…. As I found out, it was a LOT of work to lighten the Smart Car. It is anything but easy to simply add lightness.