Quote:
Originally Posted by CanAutM3
There are two types of oversteer condition that require different types throttle input for recovery.
The first comes from forward weight transfer as a result of too much deceleration. When there is less weight on the rear wheels, they will grip less and cause the car to oversteer. This usually happens on corner entry (usually when coming in too hot). The proper recovery is indeed to add slightly more throttle to transfer weight to the rear and counter steer. "Not touching the padals" and counter steering also works in this context and is easier and safer for the layman to execute, but it results in a less elegant recovery with much wasted lap time.
The second comes from power ovesteer as a result of too much acceleration. By applying more throttle, a greater proportion of the tire's grip in needed for forward thrust leaving less available for lateral grip yielding the rear to step out. This usually occurs at corner exit. The proper recovery for this type of oversteer is to slightly ease off the throttle and counter steer. Abruptly and completely lifting off the throttle here can send the car in a spin.
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Thanks! That's a great explanation and a perfect summation of what I've been taught.
Quote:
Originally Posted by ScottSinger
When cornering you at least maintain throttle - if you have four good contact patches while cornering and let off the gas or ease off the throttle or brake (assuming speeds and grip are great enough) then you can lose the rear end.
Once you lose rear grip at speed in a turn, what's the instinctive thing to do? let off the gas, also for some to brake, of course you don't brake because that will accentuate weight shift forward and you'll lose even more grip. But if you come off the pedals while over-steering, when you've already lost grip, you'll slow and bring back the rear grip.
That's the nice thing about front-engine rear drive. Mid-engine and rear-wheel drive are crazy, usually because when they lose grip they snap so fast.
Four wheel drive ? rules can be different.
Just to verify the technique for oversteer, research Vic Elford (Porsche Driving Handbook) his oversteer technique is called CPR, Countersteer, Pause, Recover.
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Four wheel drive is easy - if you're understeering you throttle off or brake to transfer weight to the front, if you're oversteering you plant the right foot, point the steering wheel where you want to go and keep your eyes on the horizon in the middle of the opening. Most (okay, Subaru) 4WD's have a tenancy for understeer, so if you've got oversteer, rejoice - you've got your trail-breaking right. I've got years of experience with these things and love them - but you can't buy a WRX as a convertible. (So, I'm relearning with RWD)
So, I think @CanAutM3 sums it up - most of the time that you're in an oversteer situation with a rwd, it's because you've done too much breaking into the apex (or onto the apex) or too much power out - so ease off. Thus it's very rare that you're correct response would be to add throttle. But the correct response is to transfer weight backwards.
So I guess the _only_ time you would want to add throttle is if you're coasting around a corner and the car oversteers - which might not be as rare a situation for Rear-engine RWD as it is for ... well, basically any front-engine car not specifically balanced to dial-out all it's understeer.
Please state any disagreement
Okay, so now I have a quite Off-topic question - why are so many expensive & coveted race & high-performance street cars mid or rear engined? Sure, they're fast, and probably better balanced - ie. faster around corners - but so much less forgiving when you find the limit. Isn't it like the difference between having one set of tyres that will let you pull 1G around a corner but gradually let go and give you a chance to recover vs. a set of tyres that will pull 1.2G around a corner, but when they let go they're gone - you're on the forums with a 'write-off part-out for sale' thread. ... I'd be choosing the former. The old adage - "To finish first, first you've got to finish".
So why the enthusiasm for rear engine?