Lightened Yaris

[HTM Yaris]

True CG is right about seat level on the transverse plane ( up , down ), but on the coronal plane ( front, back ) you have basically added 90lbs to the front . The effect of the weight reduction won't come into play until you get to a panic situation . If you ever have to make a quick lane change or a quick lane change with heavy braking you will encounter severe understeer . Also if you change gears on a turn you will encounter oversteer . I mean that the over/under steer will be more pronounced than usual .

Idahotom , check out this vid of me on track . In this vid I have done the exact same weight reduction you described . Pay special attention to 1:03 to 1:08 . That oversteer came from me just releasing the gas while turning . If I had been on stock tires the car would have probably oversteered past the point that I could recover .

http://www.youtube.com/watch?v=UCdCdT972Uk

Try a track day or autox to learn about your car's abilities . You will definately have fun while learning about your handling . Not to mention you will meet some pretty cool people .
Oh if you do decide to do Track/Autox ... your dog will need a helmet

[Idahotom]

I see what you mean, but as the coronal datum point is somewhat unknown (?) the net effect is probably less then 90 lbs., it all depends on the length of the lever arm of course. In other words, if the CDP is close to the rear seat, removing the seat would have less effect then if it (the CDP) was several feet further forward.

Having said that mouthfull, I agree that the loading is altered, and the handling. No tracks around here, but winter snow and twisty mountains roads substitute pretty well. At the outer limits of control, either track driving or a panic situation, it could well make a difference. So... did you put your seat and the other stuff back in due to your track driving insights, or is it just something to keep in mind when pushing it to the limit? I sure like the lightness as is.

The GREAT thing about hypermiling, drafting big rigs and blowing through stop signs aside, it is pretty safe, I NEVER speed anymore, I'm always in Grandma mode these days as it is all about keeping the ScanGauge happy, and I was quite amused when I saw all the aftermarket handling mods not to mention the supercharged/turboed Yaris's, who'd ever thought! All I know for sure is I got 61 MPG coming down the mountain into town, 51.8 back up, and never got over 50 mph. Good vid!

Originally Posted by HTM Yaris

True CG is right about seat level on the transverse plane ( up , down ), but on the coronal plane ( front, back ) you have basically added 90lbs to the front . The effect of the weight reduction won't come into play until you get to a panic situation . If you ever have to make a quick lane change or a quick lane change with heavy braking you will encounter severe understeer . Also if you change gears on a turn you will encounter oversteer . I mean that the over/under steer will be more pronounced than usual .

Idahotom , check out this vid of me on track . In this vid I have done the exact same weight reduction you described . Pay special attention to 1:03 to 1:08 . That oversteer came from me just releasing the gas while turning . If I had been on stock tires the car would have probably oversteered past the point that I could recover .

http://www.youtube.com/watch?v=UCdCdT972Uk

Try a track day or autox to learn about your car's abilities . You will definately have fun while learning about your handling . Not to mention you will meet some pretty cool people .
Oh if you do decide to do Track/Autox ... your dog will need a helmet