Let's talk lift induced oversteer for a moment

[sailor]

Okay, let's get back to "Lift Induced Oversteer" for a sec. here.

This is relatively minimized on a STOCK Focus because the emissions tuning does NOT allow for immediate engine braking when lifting (CAN be "tuned" to engine brake immediately, stock has a delay built in) There is still SOME of this effect just from the fronts NOT being "driven" anymore when you lift.

On a FWD car, when you "lift" it's like putting the front brakes on - nose dives, tail gets light, and it'll "step out" easier. If you are turning already, this will make the tail tend to drift more. (extreme case, if the tail is sliding already in the snow - it'll "snap oversteer" and you'll be tail first even if you steer into the slide. Been there, done that, when old RWD habits made me back off in a skid in my first FWD car)

Using this on purpose would involve steering into a turn, lifting a sec. to let the rear "rotate" a bit, then balancing the effect with throttle to continue the turn with the rear 'drifting" more than it otherwise would. This CAN result is a more "balanced" turn than FWD would otherwise allow.

The more extreme version (NOT "lift induced") is to "left foot brake" - keeping the throttle applied continuously while using the left foot to apply the brake. Engine power keeps the fronts "pulling" while the additional load on the rears from braking makes that end drift out more. It's kinda like a handbrake turn, but quite a bit more controlled.

Hope that helps keep the definitions straight, so we're talking about the same thing here.

Cheers!

[felixthecat]

Very good exspanation Sailor.

[bones33]

Mr. Fordahl knows what he is doing. Smart guy, he is. I agree with getting some track time to get used to it at the limit in a safe environment.

Stock, cars are designed to understeer even while braking, you already know this. Sounds like your car is now nearly balanced and it just requires a different driving technique.

The turn described sounds like the one from the UW to 520 eastbound. A wet. tight, dropping, blind, decreasing radius right, often with stopped traffic somewhere not visible at the entrance. Yeah, that could be interesting entering hot and not knowing where (if) there is stopped traffic.

Please take care of yourself and others and attend an autocross school and get some track time. I didn't and destroyed 2 perfectly good vehicles, luckily nobody was hurt.

[mikebontoft]

Ill have to come back and actually read but for the time being go watch season one or two of Initial D. someone explains all about fwd handling there XD

[Svizzara]

This is quoted from my showroom thread. I thought it was fairly helpful:

Originally Posted by Malibooya

Glad you want to learn! Here's why your friend crashed, aside from poor reflexes:

The Focus, unlike other economy cars of its day, has independent rear suspension. Most compacts (and even many mid-sizes) of the time used what's called a torsion beam design, which is pretty much what it sounds like. Basically a piece of steel connecting the two back wheels, so whatever one rear wheel does the other does.

Long story short, it usually means crap handling, and a lot of plowing even when lifting off (understeer). The Focus's rear suspension design allows it to give you what's known as "lift-off oversteer," which is another term that means exactly what it sounds like it does. Combine that with the Focus's short wheelbase, and you've got a lively little car even at base model trims (like your SPI).

So what probably happened: your friend was descending the hill, came in hot and lifted off while cornering and felt the rear go light. She panicked and slammed on the brakes, which caused the rear to come around even more. And BAM. There's your crash.

And this is what it led to, in my case. Stay safe out there

[jinstall]

Originally Posted by sailor

Okay, let's get back to "Lift Induced Oversteer" for a sec. here.

This is relatively minimized on a STOCK Focus because the emissions tuning does NOT allow for immediate engine braking when lifting (CAN be "tuned" to engine brake immediately, stock has a delay built in) There is still SOME of this effect just from the fronts NOT being "driven" anymore when you lift.

On a FWD car, when you "lift" it's like putting the front brakes on - nose dives, tail gets light, and it'll "step out" easier. If you are turning already, this will make the tail tend to drift more. (extreme case, if the tail is sliding already in the snow - it'll "snap oversteer" and you'll be tail first even if you steer into the slide. Been there, done that, when old RWD habits made me back off in a skid in my first FWD car)

Using this on purpose would involve steering into a turn, lifting a sec. to let the rear "rotate" a bit, then balancing the effect with throttle to continue the turn with the rear 'drifting" more than it otherwise would. This CAN result is a more "balanced" turn than FWD would otherwise allow.

The more extreme version (NOT "lift induced") is to "left foot brake" - keeping the throttle applied continuously while using the left foot to apply the brake. Engine power keeps the fronts "pulling" while the additional load on the rears from braking makes that end drift out more. It's kinda like a handbrake turn, but quite a bit more controlled.

Hope that helps keep the definitions straight, so we're talking about the same thing here.

Cheers!

Although this can be done at speed, it is not something you should try in the begining. You need to start out slow and then work your way up to higher speeds. Every driving school teaches this way.

[TommyTooHi]

Originally Posted by bones33

Mr. Fordahl knows what he is doing. Smart guy, he is. I agree with getting some track time to get used to it at the limit in a safe environment.

Stock, cars are designed to understeer even while braking, you already know this. Sounds like your car is now nearly balanced and it just requires a different driving technique.

The turn described sounds like the one from the UW to 520 eastbound. A wet. tight, dropping, blind, decreasing radius right, often with stopped traffic somewhere not visible at the entrance. Yeah, that could be interesting entering hot and not knowing where (if) there is stopped traffic.

Please take care of yourself and others and attend an autocross school and get some track time. I didn't and destroyed 2 perfectly good vehicles, luckily nobody was hurt.

good words all, thanks.
It's actually the uphill decreasing radius on ramp from 108th (Kirkland/Bellevue) onto 405 North.

speaking of understeer, my old 1985 Subaru RX, the one-of-1500 grand dad of the WRX et al, on-demand dual-range '4WD' drove me NUTS in the slippy stuff. Plow..........

-T_T