Understeer, oversteer, drifting curves, achiving best handling, 6AT, lowering

[Kushina]

335i 6AT w/ LSD, w/ alpina B3 transmission flash which allows it to redline. But it's turbo'd so do I really need to redline an AT?

Can someone thoroughly and simply explain over/understeer, what I should aim for when tuning the car. I like drifting curves but at the same time I don't want to sacrifice handling, I want the drift to be something I intentionally have to induce not something that happens on its own. Do I want to remove understeer? Why so ? How much? How?

How does lowering a car help handling ? Also on my car the previous owner lowered the front more than the rear, what effect does this have?

Staggered setups, what are they for ? I want to increase the width of the front tires to improve grip in turns/feel more planted. What am I gaining/losing with the bigger tires.

 

[Yuriman]

I'm not well versed in performance tuning, but I can probably help a little.

Understeer is when you turn your steering wheel, and the car keeps going in a straight line. Oversteer is when you turn your steering wheel and it turns too far, with the back of the car sliding out from under you around the turn. With understeer, in a worst case scenario you're going to end up off the road on the outside, while with oversteer you'll either spin, or end up going off the road on the inside of the turn.

Lowering often improves grip by lowering the center of gravity, but simply chopping springs will generally make handling worse. Get it done right.

Wider tires will have improved dry weather grip but will be more prone to hydroplaning and lose some gas mileage, which probably isn't much of a concern for a track car.

 

[jlee]

In brief- understeer is the front of your car hitting the wall. Oversteer is the back of your car hitting the wall. Lowering isn't as important as a properly set up suspension. Redline..look at a dyno plot for your car and see where you make power. With my MR2 and stock-ish cams I am better off shifting at 7k, instead of running up to 7800 (I start rapidly losing power after ~6800rpm).

 

[Kushina]

Mine starts dropping at ~6300RPM.

 

[thomsbrain]

This is a great bible for vehicle dynamics and tuning. Heed his advice, especially regarding springs and shocks.

http://farnorthracing.com/autocross_secrets3_5.html

Another flashier and less technical guide (start with the bottom article):

http://www.motoiq.com/Tech/TheUltimateGuidetoSuspensionHandling.aspx

 

[JulesMaximus]

JulesMaximus... QUIT IT... GOT IT...?

AT Moderator
Bartman39

 

[GoodRevrnd]

Widening the front tires to a square setup generally provides better turn in and may reduce understeer. Staggered gives you better cruising stability and less tramlining.

 

[thomsbrain]

Serious response: Please, for the love of GOD! Don't try to drift corners on public roads.

It's ok, he has a transmission flash and is turbo'd. He will be totally safe to do tight driftz all over residential zones and there is no chance of this ending badly.

 

[Kushina]

It's ok, he has a transmission flash and is turbo'd. He will be totally safe to do tight driftz all over residential zones and there is no chance of this ending badly.

Can't wait!! School bus hits the block at 2:55

 

[MiataNC]

Find a race track close to you and sign up for a performance driving class/clinic. You will learn more in a weekend with experienced instructors than you will ever learn driving recklessly on public roads.

 

[Fenixgoon]

Find a race track close to you and sign up for a performance driving class/clinic. You will learn more in a weekend with experienced instructors than you will ever learn driving recklessly on public roads.

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