GX 460 4/19 VSC recall (Consumer Reports "don't buy" label lifted 5/7)
05-09-10, 08:26 AM
#256
Lexus Champion
I believe the original article from CR said the GX behavior was more severe than the other 95 SUV's in their ratings. That probably included Audi, BMW, Benz etc.
05-09-10, 10:13 AM
#257
Lexus Fanatic
He was going 80mph plus in free-flowing traffic, and he never hit another car. There was no traffic impeding his travel. This was not the stereotyped southern Cal commute traffic condition that he was driving in, which has nothing to do with this particular drive.
He hit the brakes over 200 times in an attempt to stop the Prius, right... And while he was doing all of this he was making calls on his cell phone to the CHP and who knows who else.
Last edited by IS-SV; 05-09-10 at 10:26 AM.
05-09-10, 10:23 AM
#258
Lexus Fanatic
Yes and the CR video was evidence of severe and unacceptable behavior that should be controlled by any modern stability control system, resulting in the software fix later.
05-09-10, 01:00 PM
#259
Lexus Fanatic
That's why his actions were controversial. You yourself pointed out that when the Feds and technicians looked at the car, they didn't find any noticeable problems. And, by now, with all of the publicity involved after previous accelerator problems, if the pedal DID stick, instead of hitting the brake pedal 200X, simply shifting into neutral ONCE would have done it (or should have done it).
05-09-10, 01:13 PM
#260
Lexus Fanatic
A similiar situation occured in 1969, when GM became the first manufacturer to include a steering-column ignition/lock. The Government lost little time making it mandatory on all 1970 new cars the very next year, and GM did not have any patent on it after that.
05-09-10, 04:15 PM
#261
Lexus Fanatic
That's why his actions were controversial. You yourself pointed out that when the Feds and technicians looked at the car, they didn't find any noticeable problems. And, by now, with all of the publicity involved after previous accelerator problems, if the pedal DID stick, instead of hitting the brake pedal 200X, simply shifting into neutral ONCE would have done it (or should have done it).
The evidence documented by the feds and Toyota of the driver hitting the brake 200x times was key part of his actions to fake the entire UI event. No serious attempt was being made to stop the car. And none of this had anything to do with rush hour traffic in southern Cal.
Last edited by IS-SV; 05-09-10 at 09:55 PM.
05-09-10, 04:17 PM
#262
Lexus Fanatic
Back to the GX, I think it would make sense, not opnly on the GX, but on all SUVs and relatively high-center-of-gravity vehicles, to not only have conventional VSC, but a Volvo/Ford-style Roll-Control Stability-system standard as well. Conventional VSC only acounts for yaw, steering input, and understeer/oversteer, where the roll-control accounts for body-lean angle as well. Of course, the question might remain if Volvo and Ford still have exclusive-right use of that technology. But, my understanding is that, if the Government mandates something on new vehicles, patent/exclusive-rights laws are waived.
A similiar situation occured in 1969, when GM became the first manufacturer to include a steering-column ignition/lock. The Government lost little time making it mandatory on all 1970 new cars the very next year, and GM did not have any patent on it after that.
A similiar situation occured in 1969, when GM became the first manufacturer to include a steering-column ignition/lock. The Government lost little time making it mandatory on all 1970 new cars the very next year, and GM did not have any patent on it after that.
05-09-10, 07:59 PM
#263
Lexus Fanatic
The government itself sometimes does speculation as well, when mandating safety items. A good example is the required first-generation airbags in U.S.-spec cars, which were set to fire so violently that they often caused serious injuries, especially to small children. That was addressed with multi-stage bags and seat sensors for weight and other factors.
which is what CR made the issue about.
05-09-10, 09:50 PM
#265
Lexus Fanatic
Fine, call it speculation, but I don't see how anything that controls body-lean in high-center of gravity (without undue stiffening of the suspension, which would make for a harsh ride) wouldn't potentially increase the safety margin. Volvo didn't spend the time and money developing that safety-related system (as they and Mercedes have on so many other systems as well) for nothing.
The government itself sometimes does speculation as well, when mandating safety items. A good example is the required first-generation airbags in U.S.-spec cars, which were set to fire so violently that they often caused serious injuries, especially to small children. That was addressed with multi-stage bags and seat sensors for weight and other factors.
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The government itself sometimes does speculation as well, when mandating safety items. A good example is the required first-generation airbags in U.S.-spec cars, which were set to fire so violently that they often caused serious injuries, especially to small children. That was addressed with multi-stage bags and seat sensors for weight and other factors.
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Short explanation of RSC: VSC is the foundation for Roll Stability Control (RSC)that works in the vertical plane much like ESC works in the horizontal plane. When RSC detects impending rollover , RSC applies brakes, reduces throttle, induces understeer, and/or slows down the vehicle.
I agree the RSC can add a small degree of extra safety, but no where near the safety of a VSC SUV over a non-VSC-equipped SUV.
But as usual we are drifting off topic.
The GX VSC problem was discovered and documented by CR, Toyota/Lexus agreed that the problem existed and fixed it, so that story is winding down.
05-09-10, 10:08 PM
#266
Lexus Fanatic
The Volvo Roll-Stability-Control system was first introduced in 2003 on the XC90. It was also used by Ford, who had the rights to the system, on some of their SUVs as well. It has one major difference from conventional VSC systems in that conventional VSC systems, by sensors, measure steering input against what is known as understeer or oversteer, which, by definition, is how sharply the nose of the vehicle reacts in a turn relative to steering input. This left/right movement of the car's nose is known as Yaw, and, in simple terms, is similar to the left/right movement of an airplane's nose when the rudder pedals are pressed. Understeer, which you typically find in FWD, softly-sprung, and nose-heavy vehicles, occurs when the steering response of the vehicle (and the yaw/turn rate) is less than you would want (or expect it) to be....the front wheels, in other words, want to plow straight ahead instead of gripping the road in the turn. Oversteer, on the other hand, which is usually found on rear-engined, tail-heavy, more stiffly-sprung, and sometimes mid-engined cars, occurs when the steering response and yaw/turn rate exceeds the expected amount relative to steering input....in other words, the rear end of the vehicle, not the front, wants to run wide. Under severe conditions, if not corrected, this can lead to a spin-out (rear-engined Porsches used to be notorious for this).
Other factors, of course, such as tire profile height, tread compound, suspension design, power-steering/rack ratio, and many other things can affect understeer or oversteer, and I can't get into all the details here.
VSC detects and corrects for this with sensors that, according to a pre-programmed threshold (some systems are driver-adjustable, and not all have the same pre-programmed sensitivity), measure steering input against yaw rate/steering response and apply the brakes to one or more individual wheels (and/or cut engine power) to return the vehicle to a neutral cornering condition, or one where the steering input and turn rate are even. Naturally, when this happens, some speed in the turn is lost, and powersliding/drifting is impared or prevented, so auto-enthusiasts generally don't like VSC for aggressive cornering.
The Volvo (and Ford) Roll-Control systems not only perform in this manner, but add sensors that measure not only steering input against yaw/turn rate, but also that of body roll, which is similiar to the bank-angle of the wings of an airplane when the ailerons are used. Body roll angle in high-center-of-gravity vehicles like SUVs and pickup trucks, from simple physics, is much more critical in determining the risk/threshold of a roll-over than in a low-slung sports-car like, say, a Corvette or Mazda Miata. The Roll-Control sensor system, like conventional VSC, when the vehicle reaches a pre-programmed threshold of body lean, brakes one or more individual wheels and/or cuts engine power to bring the vehicle back to the intended (and safe) lean angle in the turn. So, in a nutshell, you get two layers of cornering protection instead of just one.
The GX's original problem (and CR's complaint) was that CR felt that too much slack was allowed into the VSC's reaction time, letting the rear end drift around too much (oversteer) in the turn, especially with the effective-weight-transfer that happens when the throttle is lifted. The Lexus update essentially reprograms the VSC to respond quicker to oversteer conditions.....which are considered trickier for most drivers to handle then understeer. That, of course, addresses the oversteer problem, but not necessarily body roll.....that's why, in earlier posts, I stated that I favor the use of the Roll-Control system as much as possible in high-center-of-gravity trucks/SUVs/
Last edited by mmarshall; 05-09-10 at 10:25 PM.
05-10-10, 05:35 AM
#267
Lexus Champion
Speculation is okay here. The government took documented evidence and data to prove the value of VSC, they did not rely on marketing hype and speculation on this topic. Btw, Toyota/Lexus made VSC standard on all it SUVs before the government mandate, they were also sure of its effectiveness in reducing rollovers.
Short explanation of RSC: VSC is the foundation for Roll Stability Control (RSC)that works in the vertical plane much like ESC works in the horizontal plane. When RSC detects impending rollover , RSC applies brakes, reduces throttle, induces understeer, and/or slows down the vehicle.
I agree the RSC can add a small degree of extra safety, but no where near the safety of a VSC SUV over a non-VSC-equipped SUV.
But as usual we are drifting off topic.
The GX VSC problem was discovered and documented by CR, Toyota/Lexus agreed that the problem existed and fixed it, so that story is winding down.
Short explanation of RSC: VSC is the foundation for Roll Stability Control (RSC)that works in the vertical plane much like ESC works in the horizontal plane. When RSC detects impending rollover , RSC applies brakes, reduces throttle, induces understeer, and/or slows down the vehicle.
I agree the RSC can add a small degree of extra safety, but no where near the safety of a VSC SUV over a non-VSC-equipped SUV.
But as usual we are drifting off topic.
The GX VSC problem was discovered and documented by CR, Toyota/Lexus agreed that the problem existed and fixed it, so that story is winding down.
05-10-10, 08:34 AM
#270
Lexus Fanatic