Lightened Yaris

[HTM Yaris]

Tom: for track and autox I take out the rear "junk" so that I can utilize oversteer . In the mountains I leave everything in so that I can utilize understeer . I don't want my tail to be in the opposing lane !

Jason: First of all , I really admire what you have done with the Yaris

But it is really unfair to compare your fully track prepped Yaris with a street driven Yaris . I mean your Yaris looks like it has the correct weight reduction measures ( in all 3 planes ) . I mean really , those Goodyear ( which have extra stiff sidewalls BTW )slicks are enough to keep any vehicle from tipping over Not to mention I feel you have a custom suspension among other things . Try this , put your stock Goodyears on and put your glass back in or up ( not sure if you removed/replaced your glass ) . I feel certain that the stock tires will roll onto the sidewall then the wheels will dig in to the tarmac , then loopedy loop , you will make some body shop happy

Light is might . That is correct to a point . To the point that safety is compromised .
The OP doesn't have a roll cage to stiffen the Yaris up after the reduction in weight . Nor does he have 10.5" slicks with a custom suspension . Nor does he have the driving experience(Yaris) in a panic/performance situation like Jason does .

In no way am I saying that weight reduction shouldn't be done . I'm just trying to point out the potential pitfalls . Another pitfall I forgot to mention is that the Yaris will be more likely to hydroplane with weight reduction . I can't speak for anybody else , but I would not want to be hydroplaning on the downside of a 12% grade Not saying that will happen , but the potential will be increased with weight reduction .

[Jason@SportsCar]

Originally Posted by HTM Yaris

But it is really unfair to compare your fully track prepped Yaris with a street driven Yaris . I mean your Yaris looks like it has the correct weight reduction measures ( in all 3 planes ) . I mean really , those Goodyear ( which have extra stiff sidewalls BTW )slicks are enough to keep any vehicle from tipping over Not to mention I feel you have a custom suspension among other things . Try this , put your stock Goodyears on and put your glass back in or up ( not sure if you removed/replaced your glass ) . I feel certain that the stock tires will roll onto the sidewall then the wheels will dig in to the tarmac , then loopedy loop , you will make some body shop happy

Light is might . That is correct to a point . To the point that safety is compromised .
The OP doesn't have a roll cage to stiffen the Yaris up after the reduction in weight . Nor does he have 10.5" slicks with a custom suspension . Nor does he have the driving experience(Yaris) in a panic/performance situation like Jason does .

In no way am I saying that weight reduction shouldn't be done . I'm just trying to point out the potential pitfalls . Another pitfall I forgot to mention is that the Yaris will be more likely to hydroplane with weight reduction . I can't speak for anybody else , but I would not want to be hydroplaning on the downside of a 12% grade Not saying that will happen , but the potential will be increased with weight reduction .

I would guess you have not drive on a slick... The tires are trying to pull the car over, not stick it to the ground. I have had it on two wheels at least once per race this season - more than once without clipping the curbs, just by grip alone. Street tires will not generate enough traction to pull the car over unless you hit something. As far as sidewall stiffness, that is largely offset by the fact we roll out with 19psi in the slicks, they roll on to the sidewall by design. A great way to pick up MPG is extra tire pressure, a few extra psi can help.

Less weight builds traction, as the tires are not have to work as hard to hold the weight up. More weight on a tire does not make it work more efficiently. At the initial moment of inertia the extra grip will help to prevent wheel spin, but once the car has moved even a fraction of an inch the weight is hurting efficiency.

Worrying about the effect of the trivial amount of weight you could remove and keep the car civilized for the street is a waste of energy.

If you want to use a hydroplaning example keep in mind that the inertia of the heavier car will carry it longer than the lighter car, and it will take longer to recover. You want to prevent hydroplaning, use a better tire.

Manufacturers are going to alternative lightweight materials for a many reasons... It helps fuel economy for one. Another is safety. Look at the numbers, a full size van does not fair better than a lightweight compact when it comes to occupant safety.

No one should be suggesting removal of any safety equipment, or any devices that compromise the structure of the car, but there are things that can be removed without a dangerous downside.

[why?]

Originally Posted by Idahotom

"LIGHT IS MIGHT", I like it!
My own take on adding lightness (?), at least on my Yaris, is also not to spend any money, as much as I'd like to carbon fiber everything, lighter wheels etc. Along with that, I'd rather not do anything that'd effect the resale value. While I admire the people who have the deep pockets to REALLY lighten things up, my focus is on not spending any money and making it lighter.

I've noticed just pushing it around in my shop is SO easy, and I've gotten in the habit of, after raising my shop door (converted hangar door and no remote) I just push it outside, then go back in the shop and close the door, then get in and finally start it, thus saving a minute or so of idling. Nothing like a ScanGauge to show you how idling really cuts into your mileage!

After looking at the aftermarket sway bars, I decided not to get one, too heavy! It is zippy enough on the corners as is, I'll just live with it stock. It's still pretty fun to drive! It might be too much fun with front and rear sway bars........

the front sway bar isn't really worth it, imo. the stock one is only 1 mm smaller i believe. Everyone says the rear is amazing, but I am still with you, too heavy for my tastes.

It would be different if i wanted to add power, but i really just want to add lightness.

Originally Posted by HTM Yaris

Tom: for track and autox I take out the rear "junk" so that I can utilize oversteer . In the mountains I leave everything in so that I can utilize understeer . I don't want my tail to be in the opposing lane !

Jason: First of all , I really admire what you have done with the Yaris

But it is really unfair to compare your fully track prepped Yaris with a street driven Yaris . I mean your Yaris looks like it has the correct weight reduction measures ( in all 3 planes ) . I mean really , those Goodyear ( which have extra stiff sidewalls BTW )slicks are enough to keep any vehicle from tipping over Not to mention I feel you have a custom suspension among other things . Try this , put your stock Goodyears on and put your glass back in or up ( not sure if you removed/replaced your glass ) . I feel certain that the stock tires will roll onto the sidewall then the wheels will dig in to the tarmac , then loopedy loop , you will make some body shop happy

Light is might . That is correct to a point . To the point that safety is compromised .
The OP doesn't have a roll cage to stiffen the Yaris up after the reduction in weight . Nor does he have 10.5" slicks with a custom suspension . Nor does he have the driving experience(Yaris) in a panic/performance situation like Jason does .

In no way am I saying that weight reduction shouldn't be done . I'm just trying to point out the potential pitfalls . Another pitfall I forgot to mention is that the Yaris will be more likely to hydroplane with weight reduction . I can't speak for anybody else , but I would not want to be hydroplaning on the downside of a 12% grade Not saying that will happen , but the potential will be increased with weight reduction .

what Jason said. You have it exactly opposite. stock and street tires make it harder for the car to tip over. a street tire would rather slide, not grip, and getting a street tire on the sidewalls in almost impossible.

You should note that the one known Yaris that tipped at an autocross had a stock suspension and some of the stickiest tires you can buy for the street.

And then re-read what Jason wrote.

[ctrj]

What are getting for fuel mileage with all of the weight reduction? Pencil and paper calcuations only, Scan Gauge numbers do not count!

[why?]

Originally Posted by ctrj

What are getting for fuel mileage with all of the weight reduction? Pencil and paper calcuations only, Scan Gauge numbers do not count!

so accuracy doesn't matter? lol.

[scape]

I think as tempting as it is to lighten the rear, I personally would prefer to do this only if I planned to tweak the suspension a bit. having an even heavier front end seems silly without tuning the car further.
I do think lightening the front needs less tuning overall, and has an even more drastic impact.
anyways, you can always add your notes to this thread: http://yarisworld.com/forums/showthread.php?t=17526

I was hoping we could get more of these calculations on the forums :)

[Idahotom]

Originally Posted by ctrj

What are getting for fuel mileage with all of the weight reduction? Pencil and paper calcuations only, Scan Gauge numbers do not count!

Keeping in mind I have only had my Yaris home for 3 weeks, but had a Scan Gauge on an earlier car ('98 Honda Civic, 38 mpg) so am somewhat experienced at the milder forms of hypermiling, I am getting 42 t0 43 mpg. Checked at the pump (the same pump everytime), the station I use is still 100% good old gasoline, no ethanol. Other then the weight reduction, all I have done is run the still stock tires at 44 PSI. I also use my cruise control almost all the time, even in town on long stretches (mile or so) of 35 to 45 mph streets, pretty flat though. I also use it on the interstate, even when hilly, I just like the convinence.

Having to pull a 1,000' grade every day to get home, for me anyway it makes sense and just feels right to not haul any dead weight up with me. I also like not having it with me when going down, it is a win/win. If all I did was level driving I wouldn't be quite so anal about it. I even made a point of getting a small dog, 20 lbs, and keep him on a strict diet. Sure, people tell me all the time "that dog looks like he's starving", but every little bit helps. Making him run uphill helps keep the weight down also.

[scape]

Originally Posted by Idahotom

I even made a point of getting a small dog, 20 lbs, and keep him on a strict diet. Sure, people tell me all the time "that dog looks like he's starving", but every little bit helps. Making him run uphill helps keep the weight down also.

hahaha ;)

[KrazyDawg]

Originally Posted by Idahotom

I even made a point of getting a small dog, 20 lbs, and keep him on a strict diet. Sure, people tell me all the time "that dog looks like he's starving", but every little bit helps. Making him run uphill helps keep the weight down also.

Don't forget about your own diet. ;) It's not fair to the dog. :(

[AGlobalThreat]

Originally Posted by HTM Yaris

2. Remove windshield fluid reservoir

Will there be any error codes or lights from doing this? Any negative side effects?

[mazilla]

don't forget to remove the headliner, and depending on your local codes you might only need one side mirror...I'm just sayin. ;)

[AGlobalThreat]

Haha thats my other car no joke. :)