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05-08-2009, 03:02 PM | #1 |
Drives: 2007 Yaris Hatchback Join Date: Jul 2007
Location: Beaufort, South Carolina
Posts: 388
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Weight Reductions
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/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. ----- 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. Last edited by scape; 11-12-2010 at 10:02 PM. Reason: Adding relatable threads |
05-08-2009, 03:42 PM | #2 |
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! |
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05-08-2009, 04:00 PM | #3 |
Drives: 2007 Yaris Hatchback Join Date: Jul 2007
Location: Beaufort, South Carolina
Posts: 388
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Good point, I thought about going further and listing the types of weight reductions; perhaps I'll add this in.
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05-09-2009, 03:51 PM | #4 |
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 $265 for pulleys? Also, the underdrive pulley doesn't just lighten the weight, it reduces the spin (drag) of the other components. So in the end, which is better? We will have to find someone who has bought and installed that part and ask. I think Garm might have, but I am not 100% sure. Seems like something he might have done.
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05-09-2009, 04:03 PM | #5 |
Drives: Flint Mica Sedan Join Date: Oct 2008
Location: Pittsburgh
Posts: 475
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Thinkin about takin out the spare and a few others you listed.
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05-09-2009, 04:10 PM | #6 |
I ditched my spare tire, my tools in the back, my jack and tow hook, and anything else that I would need in an emergency. I have AAA though, so if I do need something, I can call them. Also, lowering your ride height helps with the general stance and the center of gravity. Also, you should look into offsets for your ride, as the further you go out with your rims, the better and more stable your ride will be. Now, don't get too carried away, as the size and width of tires still matter a lot, but a good balance will deffinately make a difference.
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05-09-2009, 04:34 PM | #7 | |
Drives: 2007 Yaris Hatchback Join Date: Jul 2007
Location: Beaufort, South Carolina
Posts: 388
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Quote:
the stock flywheel, my guess, is about 15-17 lbs. I found a few aluminum flywheels around 8lbs for 400$, but I am unsure of the quality. ex1: http://www.dragtimes.com/Toyota-Yari...lip-16856.html ^^ this guy is using something called a JUN flywheel ~9lbs. ex2: http://www.body-kits.biz/Toyota-Yari...l-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... |
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05-09-2009, 04:41 PM | #8 |
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.
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05-10-2009, 12:33 AM | #9 |
Your mom goes to college
Drives: 08 Vitz Join Date: Oct 2008
Location: Just chillin' out brah !
Posts: 1,434
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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 . |
05-10-2009, 01:56 AM | #10 |
Learn to Relax
Drives: 2007, Meteorite, LB Join Date: Dec 2008
Location: Anaheim, CA
Posts: 2,070
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Drive naked 3 to 6 lbs.
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05-10-2009, 06:02 AM | #11 |
DWEED
Drives: 3DR 2008 Metorite Metalic Join Date: Oct 2008
Location: Arizona
Posts: 1,161
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Diet. I could easily be 20 pounds lighter.
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05-10-2009, 06:28 AM | #12 |
Where is Oahu?
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The rims do make a slight difference, my rim is about 12 pounds
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05-10-2009, 09:30 AM | #13 |
~ ambient one ~
Drives: 2009 Bayou Yaris Liftback Join Date: Jan 2007
Location: Long Island, NY
Posts: 1,046
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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.
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05-11-2009, 08:42 AM | #14 | |
Drives: 2007 Yaris Hatchback Join Date: Jul 2007
Location: Beaufort, South Carolina
Posts: 388
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Quote:
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05-11-2009, 08:44 AM | #15 | |
Drives: 2007 Yaris Hatchback Join Date: Jul 2007
Location: Beaufort, South Carolina
Posts: 388
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Quote:
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05-15-2009, 10:56 AM | #16 |
Drives: 2007 Yaris Hatchback Join Date: Jul 2007
Location: Beaufort, South Carolina
Posts: 388
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check this out:
http://www.the-welters.com/racing/rotational.html I edited the OP to reflect what I found |
05-28-2009, 11:08 AM | #17 | |
Start another Oil Thread!
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Quote:
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05-28-2009, 11:09 AM | #18 |
Carless in Chicago
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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?
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fuel efficiency, performance, reduce, weight |
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