Weight reduction and F/R Balance

[eTiMaGo]

I took out my back seat, spare tire and subwoofer from the back yesterday, and it got me to thinking... In this car it's much easier to remove weight from the back of the car than the front, meaning the overall weight shifts to the front.

So, is there a point at which having too much weight on the front of the car become detrimental to handling (increased understeer)? Or should I just stiffen my rear shocks to try and balance it out?

[scape]

that's like removing a person's weight from the back!
i'm interested in someone's opinion on this too, I've been thinking of just moving the battery to the back and not removing weight from the back, trying to even out the distribution

[Lazerdot]

Wouldn't a lighter rear end "break free" earlier in a turn allowing less under steer even if the higher weight is in the front? This if the front is allowed to grip more with less overall stiffness compared to the rear.
I've always liked a lighter stiffer rear end.

[CDavis7M]

A friends ek civic is 14k front 18k rear to get the rear rotating. Battery and fuel cell in the trunk, a/c and p/s removed from the front. It will always be front heavy. But he handles well.

[Tamago]

dont' forget to mention the motion ratio on a civic suspension, 14K civic is like 10K yaris.. rough guess of course.

honestly my car rotates just fine with everything in the rear removed. getting weight out of the car at all does a lot to the handling, and remember that you're removing weight from the "rear-center" of the car anyway, it's not like the rear seats are BEHIND the rear axle.

with everything removed from my car the weight shift went from 60/40 to 61/39. not really that big of a deal, and it was over 250lbs of crap :)

[scape]

that's like removing two women! that's a terrible thought, haha
i'm just being silly...but your right, the back seats are before the axle, has anyone done much research on reducing the front's weight?

[eTiMaGo]

Originally Posted by scape

I've been thinking of just moving the battery to the back and not removing weight from the back, trying to even out the distribution

There's been a discussion about this, the weight of the heavy gauge cables you will need to use, will really negate or balance out the advantages. Might as well get a lightweight battery up front

Originally Posted by Lazerdot

Wouldn't a lighter rear end "break free" earlier in a turn allowing less under steer even if the higher weight is in the front? This if the front is allowed to grip more with less overall stiffness compared to the rear.
I've always liked a lighter stiffer rear end.

Good question. On the one hand less weight on the wheels means less grip, on the other hand less weight to "pull" to the outside by inertia.

Originally Posted by Tamago

honestly my car rotates just fine with everything in the rear removed. getting weight out of the car at all does a lot to the handling, and remember that you're removing weight from the "rear-center" of the car anyway, it's not like the rear seats are BEHIND the rear axle.

with everything removed from my car the weight shift went from 60/40 to 61/39. not really that big of a deal, and it was over 250lbs of crap :)

Very good points there, didn't think the weight would still be considered central, yes.

Originally Posted by scape

has anyone done much research on reducing the front's weight?

Apart from lightweight battery, CF hood, and pulleys, there's not a whole lot you could do up front? lightweight plexiglass windshield?

[scape]

if it's track only, I can see plexiglass, or lexan--which is a bit more reliable i think-- working, but that will negate any DOT safety for daily driving I'm sure. I've been thinking also about trying to get a lighter exhaust manifold, I don't know how much stock weighs, but my guess is atleast 30lbs.

[Tamago]

Originally Posted by scape

I don't know how much stock weighs, but my guess is atleast 30lbs.

stock exhaust manifold will weigh far less than any aftermarket replacement. it's tubular.

[RomGrr]

Removing rear weight usually results in a loss of stability but with the Yaris I wouldn't worry. Too much weight up front and the car will fishtail under hard braking (especially if you don't have ABS). The kind of weight you are suggesting, even if taken to the extremes, will not offset the balance of the Yaris enough to really matter. A lighter rear would most likely counteract the car's natural tendency to under steer.

If I remember correctly, the Gran Turismo video game series has a car upgrade that lets you shift the weight distribution of the car? I'd just get a FWD car with specs similar to the Yaris and play around in the game with it. I imagine the results would be the ass end of the car coming alive a little.

[Morgan]

The last event I went to I left stuff in the back and ran the RComps at 32psi front/30 psi rear and did pretty well. However on less sticky tires it was easier to just have the back rotate (32psi front/40ish psi rear).... I think it depends on what/how you want the car to handle, both of the setups above were useful and fun to drive but totally different.

As for weight reduction and moving more of the weight to the center, sadly I think you could do one but not both - pick your poison!

[cali yaris]

the exhaust mani weighs about 10 pounds, I think.. lil tiny tubes and a thin flange

[David C]

Here's a picture of my 2007 2dr HB with no cargo load, single driver, front/rear axle weight at the truck scale. Pretty much 60/40 weight distribution.





About that comment on moving the battery to the rear, in my case I do have a second battery installed right behind my driver seat, it's a group 27 deep cycle which weights about 50lbs, whereas the front one is an aftermarket group 26 plain that's weight even less than the stock group 35 battery and about half of my rear battery. Both batteries are wired together with a battery switch and ACR (automatic charging relay) and using 1AWG copper cable. I could remove the front battery and the car would do just fine and the battery does weight more than the wiring needed to run from the engine bay to the rear of the car btw.

The windshield washer fluid tank under the passenger side headlight also contains a full gallon of fluid, running it almost empty or plumbing it from a rear tank would save you some weight without much hassle.

[ern-diz]

Proper zombie thread.

[David C]

Yup, Yaris never dies.