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Topic Review (Newest First)
12-05-2012 08:01 AM
TommyTooHi
Quote:
Originally Posted by bones33 View Post
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
12-05-2012 04:40 AM
jinstall
Quote:
Originally Posted by sailor View Post
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.
12-05-2012 01:06 AM
Svizzara This is quoted from my showroom thread. I thought it was fairly helpful:
Quote:
Originally Posted by Malibooya View Post
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

12-04-2012 08:50 AM
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
12-04-2012 08:34 AM
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.
12-01-2012 06:17 PM
felixthecat Very good exspanation Sailor.
12-01-2012 05:55 PM
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!
11-29-2012 11:14 PM
TommyTooHi
How do you get to Carnegie Hall?

Answer:
"Practice, practice, practice!"
haha

Cool idea - should be able to do this without new parts - it's just leaning where/when/how much\little, etc etc.

wOOt! Lots of empty lots in SoDo (when there's not a ball game!) And rain is not a problem - Seattle, ya know? No waiting.

Thanks!

-T_T

Quote:
Originally Posted by jinstall View Post
Buy a rear adjustable rear swaybar, find a very large open paved surface with no obsticals, wait fo rit to rain and start from there. Lock in the SB to it's firmest setting and use some cheap soccer cones from a local sports store. Make yourself a constant radius open 180deg turn in said area. With medium speed, 30-40mph enter the curve and as the weight shifts forward when you stab on the brakes to slow, turn the wheel to follow the curve. Whith luck the rear will step out. Once it steps out, you keep working from there as you become comfortable with the car and it's caracteristics. Most people are right handed and find it easier to do turning right. make sure you train to do it both ways. As you learn to get the car to do what you want it to do, and become good at it, change the rear swaybar to a softer setting. This will allow you to go to the next level of speed, say 50-60mph. Onece you get that down, you can move on to higher speeds and softer settings. One thing to help induce this is to raise the rear tire pressure to about 2 lbs BELOW the tire pressures rated MAX COLD PRESSURE, this will allow the tires to loose grip, not get heat and easier release of grip. Remeber alwasy to this with someone else around, in case of an accident and alwasy in an area you have LEGALLY aquired to do so at. You might want ot try a local SCCA event, after runs have been completed for the day.
11-29-2012 11:07 PM
TommyTooHi
Quote:
Originally Posted by felixthecat View Post
Quote:
Originally Posted by TommyTooHi View Post
It's known that Our Dear Focii do this, and I'd like to learn your driving habits/tips/tricks.
Stay in the throttle & use brakes to maintain momentum. The focus is a momentum car, like the mazda mx5. Have to learn to keep the speed up.
Try using your left foot on the brake= Just use a little pressure & feel weight transfer do its job. Different driving technique, takes getting use to.
Ah, beautiful response! Forgot all about that~~ I use it often, over the whoop-te-doops to keep the car planted, on the ground. Surprises those that follow... heh heh... I'll employ it from now on, thanks~~!~!~!

Quote:
Originally Posted by Neptune15 View Post
I'm curious about this too, for track purposes.

I'm a track newbie and I find even just a dab of throttle through corners keeps things stable.

Can this oversteer be used to be quicker around a track? Say, chuck the car into the corner without throttle and power out of it?
If you're into FWD drifting, maybe? See Felixthecat's response, that might be the ticket? I DO feel that as soon as the 'rotate' feeling comes, getting back on the throttle for a steady-state speed, it's gone. Same trick as on my aprilia hoon-cycle, steady state throttle is the stable/fast way around corners.

Quote:
Originally Posted by Geezer View Post
Are your toe numbers in inches or degrees? My experience is that a basically stock SVT is very neutral and not "prone" to oversteer, it has to be induced. Stiffer rear springs or larger rear sway will make the rear looser. Any car will have a tendancy to oversteer if you brake while cornering. That's why you do braking before entering a corner. Tires are also an important part of the equation. I'm assuming you do not have aftermarket camber adjustment devises on the rear end of your car. If you do, they should have been able to get the rear camber more even side to side.
I was afraid someone was going to ask that... I pretty sure he said degrees. Must be, right?

Stock (orig) rear springs, new struts/springs/end links up front (Tousley Ford Racing kit, ya?) and new rear bushings, as I mentioned. Not as noticeable as before, but: rolling through the middle of the sweeper, rolling off the throttle with no other change to inputs and it wants to rotate. Some. Not snap, just feel it... starting to rotate. Feels pretty interesting, actually.

I THINK I will learn to benefit from it, once I get comfortable and learn the dynamics. Looking forward to snow, too!!!

Quote:
Originally Posted by felixthecat View Post
Thats total toe= both sides. Seems good to me.
Thanks. one opinion I read here was rear .04 in of toe-IN.

But, I totally trust Greg Fordahl at this point. I'll give him a call and see if I can take some of his time about why OUT instead of IN - his shop is FULL of race cars in various states of reconstruction. Then there's his 914-6 track car, BITCHIN! It's about 2' wider than stock, friggin serious mods!!!

Quote:
Originally Posted by iminhell View Post
Look into the 'anti-dive' mods Gold Coast (I think it was) did to the front bushings.

The problem comes from loading the front and the back coming up. Reduce the amount the front dives and the geometry stays more predictable. Or that's the theory.

Another option may be to give the rear more braking power. An adjustable proportioning valve or using larger ID front brake lines (which would reduce braking pressure). But both these must be very well understood before attempting any modifications.
The negative results could be VERY dangerous.
Wow, but WAY too serious!!! It's my daily driver/joy toy, but good info if I decide being anal is a GOOD thing.

-T_T
11-29-2012 11:01 PM
jinstall Buy a rear adjustable rear swaybar, find a very large open paved surface with no obsticals, wait fo rit to rain and start from there. Lock in the SB to it's firmest setting and use some cheap soccer cones from a local sports store. Make yourself a constant radius open 180deg turn in said area. With medium speed, 30-40mph enter the curve and as the weight shifts forward when you stab on the brakes to slow, turn the wheel to follow the curve. Whith luck the rear will step out. Once it steps out, you keep working from there as you become comfortable with the car and it's caracteristics. Most people are right handed and find it easier to do turning right. make sure you train to do it both ways. As you learn to get the car to do what you want it to do, and become good at it, change the rear swaybar to a softer setting. This will allow you to go to the next level of speed, say 50-60mph. Onece you get that down, you can move on to higher speeds and softer settings. One thing to help induce this is to raise the rear tire pressure to about 2 lbs BELOW the tire pressures rated MAX COLD PRESSURE, this will allow the tires to loose grip, not get heat and easier release of grip. Remeber alwasy to this with someone else around, in case of an accident and alwasy in an area you have LEGALLY aquired to do so at. You might want ot try a local SCCA event, after runs have been completed for the day.
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