Vehicle Stability Control

[twostroke]

Last week I had tremendous fun with the BRZ driving across the Swiss Alps mainly using the VSC sport mode. The weather was nice and I had few good sideways and I always felt everything was under control, it was just natural like it has always been since the first day I drove the car.

On Friday night I was driving back home and it was raining, I turned left at around 40 km/h and suddenly the rear started to slide which considering the rain and perhaps some debris on the tarmac was - almost - normal. Now the problem is that the car was engaged with the standard VSC and the reaction has been awful. In fact I felt like the car was trying to cope with the loss of traction trying to compensante any input on the steering wheel, in other words it was like having the differential working like hell to maintain a straight line while turning. I was lucky because I was not driving fast, therefore I just stopped the car not far away from other cars parked on the street.

All in all electronic stability controls are good, but if you know your car and you are an experienced driver from time to time they create problems rather than helping the driver...

[atledreier]

Which is why you should ALWAYS try out your electronic "aids" when you get a new car. They all react differently, and knowing what to expect is invaluable.

Having said that, I feel mine is doing a good job, even if it is trying a bit too hard sometimes and correct very abruptly.

[Luis_GT]

That's why I disable TC all the time.

[acro]

Now funny thing you said this a friend of mine who races cars in our local series in my country said the car behaves "strangely/weird" with the VSC on sports. The last track day i turned of TC and i realised that the car responded a lot more predictably and smoothly with the TC off. Strange but true.

I think the VSC cuts in a bit abruptly

[daiheadjai]

Turning off TC is part of my routine whenever I drive now. Like OP said, the car behaves much more predictably. And IIRC you still have brake distribution and some intervention even with TC off

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[Ganthrithor]

Hmm. I haven't had this happen to me yet. I've gone from driving mine exclusively with TC off to using sport mode most of the time. I haven't had the traction control do anything strange (or really much of anything at all) lately. Once you know the car's TC-off limits, you can usually drive right up to those limits in sport mode without the car really doing much. Occasionally you get a tiny bit of rear-end squirm that you'd probably just allow to happen if you were driving unassisted that the computer will try to "correct," but all I usually feel then is a little half- or quarter-second ABS pulse at the outside front corner.

I hope this thing people talk about where the car sort of panics and goes a bit dead in the water never happens to me-- it sounds pretty unnerving.

[Ubersuber]

The stability control works by braking the rear wheel on the inside wheel of the drift, the Torsen then "tries" to send more torque to the outside wheel. When the car's orientation begins to straighten up the brake is released and the Torsen resumes sending torque across to the inside wheel. The general feel can get quite twitchy.

I don't think this VSC (or the main stability control) brakes the front wheels at all.

Basically, the stability control in fully on is designed to protect you from a big mistake. The VSC is designed to protect you from small mistake. With it off then you are on your own with the chassis which is quite good.

If you are familiar with controlling oversteer in the rain or on snow or ice you will be more comfortable with all stability controls fully off. The car will oversteer in the wet but it is very controllable.

[speargunsandracecars]

On my 1st autoX with the BRZ, I had it on VSC Sport for 1 run to get the tires warmed up. Obviously, I wasn't pushing it too hard, so it didn't intervene. In mountain roads, I generally just leave it on VSC Sport, as a safety measure. It allows a little bit more wheelspin, but the key is that it has to be a progressive wheelspin. Being smooth will allow slip angle whilst not intervening so violently, if it even intervenes at all. Haphazardly bringing the ass end out(intentional or not) will result in VSC, in normal or sport, violently intervening.

Then I tired VSC and TC off on my 2nd run in autoX. No VSC intervention. But it didn't feel right. In one of the corners, I overdrove it a little, and it plowed. I could feel the EBD kicking in to try to get me back in line. Needless to say, I wasn't a fan of it.

Then on the 3rd run, I did the 'Pedal Dance'. No nannies. Just old school sportscar driving. This is the most enjoyable way to drive the BRZ in a controlled environment. I learned how the car handles, its balance, and little nuances. It's extremely easy to drive in this mode as long as you can interpret what the car is doing. The BRZ itself is very neutral and can be coaxed to either understeer or oversteer, which is refreshing. In one of the faster left decreasing radius sweepers, the rear end stepped out in to a drift and I was able to control it very easily.

The Pedal Dance isn't something I would use on an every day basis, seeing as the car needs to be fully warmed up. And I do appreciate the VSC and TC in this platform, as it does allow you to play with it a little as long as you're smooth. My old NC MX5's VSC kicked in hard at any sign of wheelspin. What I'm loving even more is that you have the ability of to completely disable all electronic nannies. That's wonderful.

BRZ is stock.

[Alltezza]

So do you guys drive with the Sport mode on and the TC off ? I was always told that its better to be safe than to be sorry. But I've been curious to see how my car responds.

[speargunsandracecars]

Originally Posted by Alltezza

So do you guys drive with the Sport mode on and the TC off ? I was always told that its better to be safe than to be sorry. But I've been curious to see how my car responds.

I suggest running the vehicle with TC and VSC off or Pedal Danced in only controlled environments(autoX/track). Especially if you're unfamiliar with how this vehicle handles at the limit. Yes, it is easy to drive with the nannies off, but it can still bite you in the ass if you don't know what you're doing.

[Ganthrithor]

Originally Posted by Ubersuber

I don't think this VSC (or the main stability control) brakes the front wheels at all.

I could have sworn I've felt the car braking the front wheels on a skidpad before. v0v

[Ubersuber]

Originally Posted by Ganthrithor

I could have sworn I've felt the car braking the front wheels on a skidpad before. v0v

My mistake, that is correct.

However, since front braking only corrects power off oversteer you won't get this often if at all with such a low powered car.

The traction control actually controls most oversteer forces by cutting the throttle and/or braking the overpowered rear wheel.

So, you are correct that at the limit of oversteer forces the stability control will correct by braking the outside front wheel this will be very rare in our cars.

[Ganthrithor]

Originally Posted by Ubersuber

My mistake, that is correct.

However, since front braking only corrects power off oversteer you won't get this often if at all with such a low powered car.

The traction control actually controls most oversteer forces by cutting the throttle and/or braking the overpowered rear wheel.

So, you are correct that at the limit of oversteer forces the stability control will correct by braking the outside front wheel this will be very rare in our cars.

Yeah, you do have to really work at it to get sideways enough for it to brake that wheel hard. I guess it's totally possible that the ABS I get sometimes while trail-braking is the rear-- it usually blinks the light at me and you feel the slightest little nudge, but it doesn't brake anything hard or long enough to clearly feel where it's coming from.

I was really confused on the skidpad, because a couple of times I got braking of the outside front even when traction control was "disabled." Sometimes it would happen, sometimes not. It seemed like the system was keeping tabs on what you were doing and if it didn't sense that you were "keeping up" with a slide, it would apply ABS and really bog the car right down.

[kberkel]

Originally Posted by Alltezza

So do you guys drive with the Sport mode on and the TC off ? I was always told that its better to be safe than to be sorry. But I've been curious to see how my car responds.

I mostly drive with vsc on, but leave traction alone. Lets me wag the tail without the fear of spinning out since I'm still a novice to RWD.

I'll press the traction control button for fun u turns, since it turns off again at 35mph or whatever if you don't turn it off completely.

The other day in wet weather, I stupidly pushed the car on an on ramp with all the nannies on. Thank God I wasn't in VSC. It felt like the grip at the front was near the limit, and I wanted to see if it would understeer a little, so I gave it a little gas and the back end came out right as I merged. Scared the crap out of me at 60 mph. Stability control pulled me right back straight. Love this car