A lot of people always talk about making you car lighter and how it effects you hp. What about the handling?

When you reduct weight how does it effect the way the car handles?

Lets say that a car is perfectly balanced between the front and rear with suspension mods, meaning no oversteer and no understeer during “normal” or aggressive street driving.

Then you take weight off the front of the car buy adding or removing one of the following: lighter battery, lighter rims and tires, lighter struts/coilovers, (obviously you would replace all four in most cases, but for the sake of discussion I’m just talking about the front right now.), light weight bumper beam, lighter tubular swaybar.

Does taking weight off the front of the car increase oversteer or understeer?

Now I’m not asking what happens if you change all of these things at once. They are just examples of what you could change to reduce weight up front. I Just basically want to know what happens to your car when you reduce weight up front.

Lowball

 

In my head, it seems like reducing weight up front would increase understeer, and reducing weight in the back would increase oversteer. My theory is that less weight=less grip for those tires. Not tested, just what seems right in my head.

 

I actually must disagree, although I'm not positive. Cars with heavy backs, porsche 911, corvair, etc. naturally oversteer way more. This is caused by the back being heavy and wanting to go out more (cyntrifical (sp) force) or something. Now I'm not sure it would make much difference but I'm almost positive that taking weight off the fron would make it oversteer, weight off the back understeer.

 

Good point. I didn't even think about centrifical force. I think we need someone who has tested this to let us know...

 

Yeah this is my whole reason for posting. Just wondering if anyone has a good answer. I was thinking along the lines of less weight up front = understeer as well. But maybe not!

The reason I'm asking is a couple. One I installed a FMIC. So I removed the TMIC, factory air box, and factory bumper beam (which weighed a ton more than the FMIC that I added). Also, I'm thinking about getting the cobb tubular sway bars which are also light. Oh and I added a light weight battery.

I just want to know what to expect from my car the 1st time I drive it and don't make any suspension changes.

I remember when I added the Perrin rear sway bar and end links the over steer was dramatic and almost scared the crap out of me! But I kept it under control

LB

 

With those changes, I'd be surprised if you noticed a difference in the handling without further suspension revisions.

 

in general, the biggest advantage to reducing weight is reducing the amount of inertia that has to be overcome when attempting to change the direction of the car's travel. After that, playing with the weight balance will definately affect the handling, as was noted earlier, by affecting the amount of weight on each set of tires. If you have more weight in the front (like most street cars), there is a larger amount of weight on the front of the car, and also a larger amount of inertia to be overcom by the front of the car, therefore this tends to induce understeer, since the front of the car wants to continue on in the same trajectory. Balancing out the weight distribution will help (along with suspension adjustments) to make for a more neutral handling car.

 

platypus - so basically it will not have any real effect on handling is what you are saying. But more back on the whole less weight = a few seconds faster car because it take less to get the car rollin' deal.

Cool

Thanks for every ones replys. Just thought it may be some what of an issue. But if it is I can do some adustments to the suspension.

LB

 

its probably a moot point now, but I thought of some more specific, and different examples all of which support my earlier statement! If u look at weight distribution of almost any new car, most will be slightly biased forward, like the wrx, and all of these seem to have understeer whereas more sporty cars, for example a porsche 911, have slighly more in back than in front, or some are just equal. the optimum for a performance car would be split perfectly 50/50.

Another example, although this is kind of old, is my dad's 1960 corvair which was is rear engine car. when it came out, some people complained about the handling cuz of the oversteer, and it beeing an economy, not sport car (yenko stinger pwned stingrays by the way, and gm had to detune them) anyway, some people who swapped in different engines did this to the front and it caused severe understeer.

And finally the old porsches again. With the rear engine, some people were freaked by them and to make them more equal actually added sand bags to the trunk (in the front) to equilize weight and reduce oversteer.

Hope this helped!

 

Im pretty sure decreasing the weight in front will reduce understeer. Think about it, the cars in the WRC all work to make the car 50/50 front and rear and I dont think they are working to increase understeer since they kick the rear out so much. That being said, do you think in a F1 car you would add more front downforce to help with understeer?

 

For the F1 cars: More downforce means more tire traction (reduce understeer) without added weight (increase understeer). Makes sense that more front downforce would cause less understeer.

Lowball, the Perrin's are adjustable right? Which setting did you have it on when you noticed the oversteer. I'd like them too but am a bit afraid of having to deal with the oversteer you described.

 

I had the Perrin rear bar which is adjustable. I had it on the least progressive setting with the Perrin endlinks and it seemed to create oversteer on my wagon. I took off the Perrin endlinks and put the stocks back on and it calmed down a bit to where I liked it very much.

I ended up selling the whole Perrin setup because I added the STi endlinks, trailing arms, and lateral link set up. The Perrin bar wouldn't work with the set up otherwise I would have kept the bar. The HD mounts that it comes with is a very nice set up.

LB

Now I have the Sedan rear sway bar.

 

Mo Rex don't confuse weight with down force. One carries momentum the other does not. For example downforce builds up with speed where as weight is pretty much constant and does not change with speed. Downforce is ideal because it increases pressure between the tires and the ground, thus increasing grip, which inturn helps us corner better. Weight also increases grip but carries inertia. Sorry my physics classes are kicking in .... Later