Weight Reductions

[scape]

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)

----
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/display_topic_threads.asp?ForumID=17&TopicID=116506&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.
-----

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.

[eric81]

Although they pulleys are 5 lbs lighter, and the wheels are 10 lbs lighter, they both fall under a different type of weight class. You have dead weight (battery, seats, hoods, windows, etc...) and then you have rotating mass (pulleys, cams, pistons, tranny, flywheel, wheels, axels, ... anything that rotates with the engine to cause you to move foreward.) Now, the car originally weighs 2,300 lbs. If you remove 5 lbs of dead weight, you probably won't even notice it. However, if you remove 5 lbs rotating mass (i.e. pulleys) you WILL notice a difference. That's simple science and the less drag on the engine, the more HP you will have and faster you can get your engine up to it's peak power points. Dead weight matters too, just not on such a great scale.

Pour more money into the engine and tranny area, and you'll notice a larger difference. There is a flywheel that is supposed to be over 50% lighter than stock for around $600 or so. Might be a good point to do some real research. Before and after times or dyno's would be AWESOME!

[scape]

Good point, I thought about going further and listing the types of weight reductions; perhaps I'll add this in.

[eric81]

Dead weight is good to be rid of for turning and stuff, so don't get me all wrong on just focusing on rotating weight. Just wanted to point out the different types of weight. I was looking into the flywheel vs pulleys for weight difference vs price (weight per lb) but no one can tell me how much the stock flywheel weighs, and the aftermarket one says it weighs 18 lbs, but is that worth the $600 for that vs the $265 for pulleys? Also, the underdrive pulley doesn't just lighten the weight, it reduces the spin (drag) of the other components. So in the end, which is better? We will have to find someone who has bought and installed that part and ask. I think Garm might have, but I am not 100% sure. Seems like something he might have done.

[Pitt Yaris]

Thinkin about takin out the spare and a few others you listed.

[eric81]

I ditched my spare tire, my tools in the back, my jack and tow hook, and anything else that I would need in an emergency. I have AAA though, so if I do need something, I can call them. Also, lowering your ride height helps with the general stance and the center of gravity. Also, you should look into offsets for your ride, as the further you go out with your rims, the better and more stable your ride will be. Now, don't get too carried away, as the size and width of tires still matter a lot, but a good balance will deffinately make a difference.

[scape]

I ditched my spare tire, my tools in the back, my jack and tow hook, and anything else that I would need in an emergency. I have AAA though, so if I do need something, I can call them. Also, lowering your ride height helps with the general stance and the center of gravity. Also, you should look into offsets for your ride, as the further you go out with your rims, the better and more stable your ride will be. Now, don't get too carried away, as the size and width of tires still matter a lot, but a good balance will deffinately make a difference.

new tires is my next purchase, since I won't be going larger than 15" in size for the rim, I can re-use the tires when I have money for the rims :rolleyes:

the stock flywheel, my guess, is about 15-17 lbs. I found a few aluminum flywheels around 8lbs for 400$, but I am unsure of the quality.

ex1: http://www.dragtimes.com/Toyota-Yaris-Timeslip-16856.html
^^ this guy is using something called a JUN flywheel ~9lbs.
ex2: http://www.body-kits.biz/Toyota-Yaris-NCP91-Engine-Drivetrain-C-One-Lightweight-Flywheel-p-73159.html
I also found a SPEC flywheel as well.

as for the underdrive pulley, I'm not sure how much that helps. I am interested in using aluminum pulleys and ditching the stock.

I think it's interesting that losing weight is easiest in the rear, it seems. which is a shame because a lighter front would be great for turning. has anyone moved the battery to the back? that'd be cheaper than buying a smaller battery, and improve handing by a few more lbs. in the front...

[eric81]

Only problem with that is there is more electrical loss going from the alt. to the battery and back to the engine. If that is done, I would recommend getting a spark enhancer (like the kind used for Turbo's and Super's, or making the gap a tad smaller, just to make sure you don't miss-fire). Also, instead of paying so much for replacement pulleys, you could always try and just drill holes in the stock ones to lighten them. Not saying it's smart or safe, just money saving. I think I will try it and post results from one drag to the next. There s a track right down the road from me, so I hope to go there one of these days soon.

[blacksandiegovitz]

So far i've done:
Cf hood and hatch+ removed rear wiper motor/arm
took out the back seats/seatbelts/spare tire / tire cover /hatch cover
switched my front seats with recaro fixed bucket seats
switched the steering wheel(airbag) with nardi/works bell quick release hub
removed jack

Plan on switching out to the 11lbs braille battery next
lightweight flywheel
and some lightweight 15" rims to get the rotating mass down .

[yaris-me]

Drive naked 3 to 6 lbs.:thumbup:

[nemelek]

Diet. I could easily be 20 pounds lighter.

[808_Yaris]

The rims do make a slight difference, my rim is about 12 pounds

[Treyz]

Hmm .. pretty interesting read that someone actually listed it out lol.

YOu should have seen my last car .. the 240SX. Gutted the hell out of it and when it came to race day at the track, the passanger seat came out as well.

[scape]

Only problem with that is there is more electrical loss going from the alt. to the battery and back to the engine. If that is done, I would recommend getting a spark enhancer (like the kind used for Turbo's and Super's, or making the gap a tad smaller, just to make sure you don't miss-fire). Also, instead of paying so much for replacement pulleys, you could always try and just drill holes in the stock ones to lighten them. Not saying it's smart or safe, just money saving. I think I will try it and post results from one drag to the next. There s a track right down the road from me, so I hope to go there one of these days soon.

I shared a volvo s80 for a while, and it was an inline 6 with the battery in the back-- though there were terminals in the front as well. they may have rerouted some of the power directly to the electrical components as well as to the battery (which sounds right to me b/c it should only be necessary for starting and running regular electronics with the engine off).

[scape]

So far i've done:
Cf hood and hatch+ removed rear wiper motor/arm
took out the back seats/seatbelts/spare tire / tire cover /hatch cover
switched my front seats with recaro fixed bucket seats
switched the steering wheel(airbag) with nardi/works bell quick release hub
removed jack

Plan on switching out to the 11lbs braille battery next
lightweight flywheel
and some lightweight 15" rims to get the rotating mass down .

any idea how much you saved in lbs with the new seats?

[scape]

check this out:
http://www.the-welters.com/racing/rotational.html

I edited the OP to reflect what I found

[Tamago]

http://i40.photobucket.com/albums/e239/fatherdutami/Project%20Angry%20Panda/P1000900.jpg

http://i40.photobucket.com/albums/e239/fatherdutami/Project%20Angry%20Panda/P1000904.jpg

http://i40.photobucket.com/albums/e239/fatherdutami/Project%20Angry%20Panda/P1000901.jpg

[m911gt]

Wow, that's quite a difference Tomago, nice post.

I know it's nothing major, but anybody know how much the three rear seatbelts and their assemblies weigh?

[Tamago]

belts with tensioners tend to weight 2lbs each.

http://i40.photobucket.com/albums/e239/fatherdutami/Project%20Angry%20Panda/belt.jpg

[Tamago]

Wow, that's quite a difference Tomago, nice post.

I know it's nothing major, but anybody know how much the three rear seatbelts and their assemblies weigh?

on the subject of clutches, my Spec Stage 3 weighed about 3 lbs more than stock clutch/pressureplate.. so if you stick to stock clutch you're gonna save 3 more pounds.

i'm now on a 4 puck unsprung disk, half the weight of the 6 puck sprung pictured.

[m911gt]

Great, thanks Tomago...I removed the three of mine a couple weeks ago and they felt like a few pounds each.

[m911gt]

on the subject of clutches, my Spec Stage 3 weighed about 3 lbs more than stock clutch/pressureplate.. so if you stick to stock clutch you're gonna save 3 more pounds.

i'm now on a 4 puck unsprung disk, half the weight of the 6 puck sprung pictured.

I see, so you have had 2 aftermarket clutches then? What are your impressions?

[Tamago]

I see, so you have had 2 aftermarket clutches then? What are your impressions?

http://www.yarisworld.com/forums/showthread.php?t=14837&highlight=spec+stage

[m911gt]

http://www.yarisworld.com/forums/showthread.php?t=14837&highlight=spec+stage

:eek: That answers my questions, ouch.

[Tamago]

:eek: That answers my questions, ouch.

the pressure plate is awesome

disk not so much

i LOVE my 4 puck unsprung disk + spec pressure plate :)

[SilverGlow]

Becareful with weight saving replacement parts...the savings in gas could take years or 100,000+ miles to recoup your costs...I would suggest one do the math before laying out $$ on improvements for saving gas....not saying it's a bad idea, just saying it offend is not cost effective.

[m911gt]

Becareful with weight saving replacement parts...the savings in gas could take years or 100,000+ miles to recoup your costs...I would suggest one do the math before laying out $$ on improvements for saving gas....not saying it's a bad idea, just saying it offend is not cost effective.

I think many of us reduce weight not to save gas necessarily, but to improve acceleration.

[Tamago]

i get 18mpg and i love it lmfao

[m911gt]

i get 18mpg and i love it lmfao
hahaha

[scape]

Becareful with weight saving replacement parts...the savings in gas could take years or 100,000+ miles to recoup your costs...I would suggest one do the math before laying out $$ on improvements for saving gas....not saying it's a bad idea, just saying it offend is not cost effective.

true, but if tires came in lighter weights, that'd be a no-brainer I think. I'm not sure why more work isn't being done on making tires better, or at the least no longer vulcanized rubber

[Tamago]

true, but if tires came in lighter weights, that'd be a no-brainer I think. I'm not sure why more work isn't being done on making tires better, or at the least no longer vulcanized rubber

light tires suck though..

i'd sacrifice 1lb of tire weight for the rigidity it offers :)

[Yaris Hilton]

Tires are a very mature technology. They aren't perfect, but they really do a pretty good job.

[scape]

perhaps, I just think for something as huge as tires there should be a bit more done to them

[eTiMaGo]

perhaps, I just think for something as huge as tires there should be a bit more done to them

http://en.wikipedia.org/wiki/Tweel

the future of wheels? :iono:

[scape]

haha