Quote:
Originally Posted by Logic
Hmmm... that's debatable Ecky.
Shaving off excess bolt lengths and getting rid off excess metal (Drilling for lightness) in various brackets etc adds up and is easy to tackle in bite size chunks without the car being out of commission.
Shooting yourself in the foot with heavy and impractical boat tails and such just because 'that's easy to do low hanging fruit' is what I am ...er... weighing up. 
That's the reason for this post.
That makes it unpopular but facts are facts...
(Can't be less popular than the the Boric Acid thing!  )
Er...? I'm not understanding this bit?
800lbs of added weight specifically 'for aero' in a typical car?? |
How I meant it was, the typical new vehicle weighs near 2 tons. 20% from that is 800lbs, or ~400 kilos. That's a lot of weight to remove, and, having seen some cars go on extreme weight loss diets, I'm of the opinion it is wildly out of reach. A percent of weight loss may be more useful in most driving scenarios than a percent of aero, but a percent of aero is a lot easier to achieve.
As an example, one forum member here did an extreme weight loss diet in a 2004 Saturn Ion. It started at ~26xx and ended (if I recall correctly) at 23xx. To get there, he removed the interior, removed all seats but the driver seat, lightweight battery, cut the support webbing out of the hood and trunk, cut the crash beams out of the doors, and took a hole saw to and made swiss cheese of every bit of sheet metal that didn't face the outside. He cut the floorpan out of the car behind the rear seats and replaced it with coroplast. Door latches deleted. Window hardware deleted. Speakers and "unnecessary" lights deleted. Exhaust deleted. Power steering, engine balance shafts, A/C deleted. You name it, he cut it out. I believe he didn't quite reach 15% weight savings.
I'm not advocating everyone build boat tails, but MetroMPG found a boat tail (alone) on his Insight (an already very slippery car) to improve ABA fuel economy by 10% on the highway. That suggests a near 20% improvement in Cd from that piece alone. I guess you can get at least half that from a small rear kamm or well placed spoiler, front grille block, smooth underbody, smooth wheel covers and rear spats - most of which I could put together in an afternoon with $50 in materials, and which would not alter the function of the car in any way.
Simply put, weight savings are great (I do them too), but they're much harder and more expensive.