Weight Reductions

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I did not know where to put this, or if it already exists on here (I coudn't readily find anything), and technically is could fall in a few topic categories (Performance, Fuel Economy, etc.) but...

I think a compiled listing of all of the weight reduction methods would be helpful.

If you're interested or if my numbers are way off, please chime in!


Rotating Mass Reductions:
Wheels covers: ~3.5lbs
Lighter wheels: 1-10lbs, each wheel (Volk 14", ~10lbs lighter)

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Lighter Tires/Smaller Total Diameter Tires
This seems to be a larger determining factor than wheel weight...
Because the weight is at the farthest reach of the rotation, it has a huge impact, even 1-2 lbs has a massive effect.
On here: http://www.the-welters.com/racing/rotational.html
is a spreadsheet to dial in some numbers and get a guestimate of dead weight equivalence through physics.

I inputed this:
Car and Wheel Dimensions: wheel 1 wheel 2
Wheel size (inches) 15 15
Tire width (mm) 185 195
aspect ratio 60 55

wheel weight (lbs) 17 13
tire weight (lbs) 19 21
Total wheel weight 36 34

Car weight (with wheel style 1) 2350
Engine Torque 103
Engine HP 106

Car 0-60mph time 10.8

The result is that tire+wheel #2 is 2lbs dead-weight heavier. If the tire weight of wheel 2 combo is changed from 21 to 18 (there are a few that exist that light) the effect is massive, equating to a ~70lbs drop in dead weight.

Download the spreadsheet and play around with it, you'll see what I mean.

Tirerack has a tire weight listing for each brand, as well here is a small compilation I found.
tire weight listing: http://www.team-integra.net/forum/di...PagePosition=1

So what does this all mean to me? If you keep stock steel wheels and simply buy tires that are lighter and slightly lower profile, the dead weight savings is equivalent to almost 30lbs drop in dead-weight, or 1.5hp, just by selecting tires. (195/55/15 @ 18lbs == 32lbs, 195/50/15 @ 18lbs == 49 lbs)

The extreme of this could be: Volk 14" (te37, 14x6, ~8lbs) with a 195/45/14 tire (toyo tr1, ~15lbs) would be a weight savings of 235lbs chassis weight.
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Alloy pulleys: ~5lbs front reduction

Flywheel: ~10 lbs front reduction



Dead Weight Reductions:

Carbon fiber hood, hatch, paneling: 5-15lbs front and back reduction

Smaller battery: 5-20lbs front reduction (smallest Braille, ~20lbs lighter)

Bucket Seats: x lbs, mid-front reduction

Back Seat Removal(Standard not Split): ~55 lbs mid-rear reduction

Muffler (Alloy/Carbon): ~5 lbs/8 lbs rear reduction

Lexan rear-window: ~30-50lbs rear reduction (Not sure how legal this is)

Remove spare tire+jack: ~25lbs rear reduction

Owners manual: ~2.0lbs front reduction

Flip up deck ~2 lbs rear reduction
Deck carpet ~2 lbs rear reduction
Tool trays with tools ~7 lbs rear reduction

Steering wheel replacement (from stock+airbag): ~2-5lbs? driver-side front reduction

note: I do not know the weights of all items, and thus put an 'x' and is not calculated in total

dead weight total: ~70-180 (-100lbs dropped == +4.5 hp)


more to come...


edit: found these thread about someone who has reduced their car's weight
http://www.yarisworld.com/forums/showthread.php?t=3176
http://yarisworld.com/forums/showthread.php?t=31397

Just to put things in to perspective: the power to weight ratio of the yaris hatch is about 1:22.8, so for every ~23lbs dead weight we drop, in a way that is the equivalent of +1 hp; consequently, at 100lbs dropped, it will be closer to 1:20 ratio, so less weight is needed for each additional hp after that.