I have been autocrossing for many years, most recently with an 03 Corvette Z06.

For the last event, I took the GXP out just for fun and ran it on the RSA street tires. It performed very well, was easy to control and responded nicely to inputs. Although, the tire traction was rather poor, as expected.

My question to others who have autocrossed their G8 or GXP: Does the Electronic Stability Control remain active when the switch is turned off and the display says "ESC OFF"? I ask this because when driving the course with the switch off, I am certain I could feel the ESC engaging on the more agressive turns, when the car was just starting to get loose.

I did not try a run with the ESC on to compare, but it seems that the system remains active, only at more extreme conditions.

Anyone else with similar experience?

Just for fun, I had a passenger video with a hand held camera on one of my runs. If I can get it on You Tube, I will post a link.

Hi,
I've been autocrossing off and on for more than 5 years in a camaro and a few other cars. I ran a couple autocrosses in my gxp recently just to get a feel for the car, and have been wondering the same thing.
I have the potenzas from the factory (summer tires), and they are suprisingly sticky for narrow oem street tires, although they will of course get greasy after a few hard runs.

The gxp really surprised me! It can be easily balanced with the throttle, puts down the power nicely and rotates well for such a big car. However, I have yet to get the car way "out of shape" despite some aggressive runs and even some overdriving, so you got me thinking...

Here is what I do know: I've tried both ESP on and off. with the ESP on and smooth driving, it is surprisingly forgiving in slaloms/sweepers, and will actually let you slide the car a bit with only a little intervention. Where it will KILL you is on corner exits, as it aggressively pulls timing for several seconds if you try to unwind the wheel and quickly feed in throttle. This isn't scientific as I'm still learning the car, but with the ESP off after a decent run with it on, I was several seconds quicker. You will know when it is on, like when I forget to turn it off :slap:

I can't say for certain whether it was "helping" me when esp was off as I didn't feel any strange corrections, honestly, but I probably could push the car harder as I am not competing with it and am not running r-comps on it.

One idea is check the brakes right after your run, particularly the rear brakes as they shouldn't do too much work during a run. If either of them or any particular brake corner is scorching hot, then I'd say esp kicked in. If I take the gxp to an autox again I'll check this myself.

One other idea: if you are very consistent and have a datalogger that records lateral Gs, you might be able to see where it tries to correct your line.

What else I can say for certain is that in a straight line (not at an autocross), if you shift very VERY aggressively with the esp OFF, it will turn esp back ON, presumably to protect the driveline. But...you will see that the ESP is back on in the center display (it no longer says it is off).
I have never seen this happen at an autocross, even with aggressive launches on concrete (factory tires).

Hope that helps.

V

Although I really don't have an answer to this question, I thought I would post this bulletin regarding the ABS system. I do not believe you can turn off anything other than T/C.

2009 Pontiac G8 | G8 Service Manual | Document ID: 2043131
ABS Description and Operation

This vehicle is equipped with a Bosch ABS/EBD/TCS/VSES brake system. The electronic brake control module (EBCM) and the brake pressure modulator valve (BPMV) is serviced separately. The BPMV uses a 4 circuit configuration to control hydraulic pressure to each wheel independently.

The following vehicle performance enhancement systems are provided.
• Antilock Brake System (ABS)
• Electronic Brake Distribution (EBD)
• Traction Control System (TCS)
• Vehicle Stability Enhancement System (VSES)

The following components are involved in the operation of the above systems.
• ABS pump motor--The ABS pump motor is part of the brake pressure modulator valve. The ABS pump motor is active during ABS, VSES and base brake power assist functions.
- System relays--There are two system relays internal to the EBCM. The solenoid relay is energized when the ignition is ON. The ABS pump motor relay supplies a ground path to the ABS pump motor when the EBCM commands the ABS pump motor on. The system relays are non serviceable.
- Solenoids--The solenoids are commanded ON and OFF by the EBCM to operate the appropriate valves in the brake pressure modulator valve (BPMV).
• Brake booster vacuum sensor--The Brake Booster Vacuum Sensor is a input to ECM.
• The BPMV contains the ABS pump motor and pump.
• Lateral accelerometer--The EBCM uses the lateral accelerometer to determine the sideways acceleration of the vehicle. The lateral accelerometer is packaged with the yaw rate sensor as a single component.
• Master cylinder pressure sensor--The master cylinder pressure sensor is located within the BPMV. The master cylinder pressure sensor uses a 5-volt reference and generates an output signal proportionate to the hydraulic fluid pressure which is present in the front brake circuit at the master cylinder.
• Steering wheel position sensor--The steering wheel position sensor is an input to the EBCM.
• Traction control switch--VSES and the engine torque reduction function of TCS are manually disabled or enabled by pressing the traction control switch.
• Wheel speed sensors (WSS)--EBCM sends a 12-volt reference voltage signal to each wheel speed sensor. As the wheel spins, the wheel speed sensor produces a square wave DC signal voltage. The wheel speed sensor increases the signal frequency as the wheel speed increases, but does not increase the signal amplitude.
• Yaw rate sensor--The EBCM uses the yaw rate sensor to determine the rate of rotation along the vehicle's vertical axis. The yaw rate sensor is packaged with the lateral accelerometer as a single component.
Antilock Brake System (ABS)

When wheel slip is detected during a brake application, an ABS event occurs. During antilock braking, hydraulic pressure in the individual wheel circuits is controlled to prevent any wheel from slipping. A separate hydraulic line and specific solenoid valves are provided for each wheel. The ABS can decrease, hold, or increase hydraulic pressure to each wheel. The ABS does not, however, increase hydraulic pressure above the amount which is transmitted by the master cylinder during braking.

During antilock braking, a series of rapid pulsations is felt in the brake pedal. These pulsations are caused by the rapid changes in position of the individual solenoid valves as the electronic brake control module (EBCM) responds to wheel speed sensor inputs and attempts to prevent wheel slip. These pedal pulsations are present only during antilock braking and stop when normal braking is resumed or when the vehicle comes to a stop. A ticking or popping noise may also be heard as the solenoid valves cycle rapidly. During antilock braking on dry pavement, intermittent chirping noises may be heard as the tires approach slipping. These noises and pedal pulsations are considered normal during antilock operation.

Vehicles equipped with ABS may be stopped by applying normal force to the brake pedal. Brake pedal operation during normal braking is no different than that of previous non-ABS systems. Maintaining a constant force on the brake pedal provides the shortest stopping distance while maintaining vehicle stability. The typical ABS activation sequence is as follows.
Pressure Hold

The EBCM closes the isolation valve and keeps the dump valve closed in order to isolate the slipping wheel when wheel slip occurs. This holds the pressure steady on the brake so that the hydraulic pressure does not increase or decrease.
Pressure Decrease

If a pressure hold does not correct the wheel slip condition, a pressure decrease occurs. The EBCM decreases the pressure to individual wheels during deceleration when wheel slip occurs. The isolation valve is closed and the dump valve is opened. The excess fluid is stored in the accumulator until the pump can return the fluid to the master cylinder or fluid reservoir.
Pressure Increase

After the wheel slip is corrected, a pressure increase occurs. The EBCM increases the pressure to individual wheels during deceleration in order to reduce the speed of the wheel. The isolation valve is opened and the dump valve is closed. The increased pressure is delivered from the master cylinder.
Electronic Brake Distribution (EBD)

The electronic brake distribution (EBD) is a control system that enhances the hydraulic proportioning function of the mechanical proportioning valve in the base brake system. The EBD control system is part of the operation software in the electronic brake control module (EBCM). The EBD uses active control with existing ABS in order to regulate the vehicle's rear brake pressure.
Brake Pressure Application

The EBCM uses brake pressure application to control traction by transferring torque through the driveline to wheels which are not slipping. The ABS pump motor, and appropriate valve solenoids are commanded ON and OFF to apply brake pressure to the slipping wheels. Brake pressure application is used in an attempt to maintain equal wheel speed sensor (WSS) signals at the driven wheels.

The EBCM does not allow excessive brake pressure application due to the fact that the solenoid coils or the brakes may become overheated, damaging the EBCM or reducing the drivers ability to stop the vehicle. Estimated coil and brake temperatures are determined by a calculation in the EBCM software. Overheated solenoid coils cause all brake pressure application to become disabled and the stability system disabled message to be displayed. Overheated brakes cause brake pressure application during TCS events to disable, yet the VSES remains functional and as long as the engine torque reduction is enabled, there is no indication to the driver when this occurs and no DTC sets.

Vehicle Stability Enhancement System (VSES)

Vehicle stability enhancement system (VSES) provides added stability during aggressive maneuvers. Yaw rate is the rate of rotation about the vehicle's vertical axis. The VSES is activated when the electronic brake control module (EBCM) determines that the desired yaw rate does not match the actual yaw rate as measured by the yaw rate sensor.

The desired yaw rate is calculated by the EBCM using, primarily, the following inputs.
• The position of the steering wheel
• The speed of the vehicle
• The lateral, or sideways acceleration of the vehicle

The difference between the desired yaw rate and the actual yaw rate is the yaw rate error, which is a measurement of oversteer or understeer. When a yaw rate error is detected, the EBCM attempts to correct the vehicle's yaw motion by applying brake pressure to one or more of the wheels. The amount of brake pressure which is applied varies, depending on the correction required. The engine torque may be reduced also, if it is necessary to slow the vehicle while maintaining stability.

VSES activations generally occur in turns during aggressive driving. When braking during VSES activation, the pedal may pulsate. The brake pedal pulsates at a higher frequency during VSES activation than during ABS activation.

Power-Up Self-Test

The electronic brake control module (EBCM) is able to detect many malfunctions whenever the ignition is ON. However, certain failures cannot be detected unless active diagnostic tests are performed on the components. Shorted solenoid coil or motor windings, for example, cannot be detected until the components are commanded ON by the EBCM. Therefore, a power-up self-test is required at the beginning of each ignition cycle to verify correct operation of components before the various control systems can be enabled. The EBCM performs the first phase of the power-up self-test when the ignition is first turned ON. The system relay, solenoids and the ABS pump motor are commanded ON and OFF to verify proper operation and the EBCM verifies the ability to return the system to base braking in the event of a failure. The master cylinder pressure sensor performs a self-test by sending a series of specific voltage signals to the EBCM, each for a predetermined amount of time. This phase of the power-up self-test may be heard by the driver, depending on how soon the engine is cranked and started after turning ON the ignition. The second phase of the power-up self-test begins when the vehicle is driven at a speed greater than 12 km/h (7.5 mph) and the EBCM has not detected any traction control module (TCS)/vehicle stability enhancement system (VSES) related malfunctions thus far. When the brake switch indicates that the brake is not applied and the master cylinder pressure is detected as being low, the EBCM proceeds with the test. The EBCM isolates all of the wheels by closing the 4 isolation valves. Due to the fact that all of the wheels are isolated during the second phase of the test, the test must be aborted if the brake is applied while the test is being performed. Occasionally, the driver may detect this by experiencing a momentary hard pedal.

VSES Sensors Initialization

The vehicle stability enhancement system (VSES) sensors values may vary slightly due to differences in temperature, sensor mounting, connector resistances, manufacturing, etc. Since VSES is a very sensitive and precise control system, it is imperative that the electronic brake control module (EBCM) be able to accurately equate a given sensor voltage with an actual unit of measurement. For example, the yaw rate signal of one vehicle may be 2.64 volts at +18.0 deg/sec yaw rate while the yaw rate signal of another vehicle may be 2.64 volts at +17.5 deg/sec yaw rate. Therefore, at the beginning of each ignition cycle, the EBCM must perform an initialization procedure to observe how the VSES sensors are correlated with each other and also to determine what each sensor value is when the applicable unit of measurement equals 0. This voltage is referred to as the sensor bias voltage. Although some activation of the VSES system may occur if required to prior to full initialization, the system does not give optimum performance until the sensors are fully initialized.

The following VSES sensors require initialization:
• The yaw rate sensor
• The lateral accelerometer
• The master cylinder pressure sensor
• The steering wheel position sensor

When the vehicle speed is greater than 25 km/h (15 mph), full sensor initialization must occur during 3 km (1.8 mi) of driving or 1 km (0.6 mi) of straight and stable driving, whichever occurs first. Although an attempt at initialization may fail due to driving conditions, such as driving on a very winding road, failed initialization is usually caused by a sensor bias voltage which is not within an acceptable range. Often, a DTC sets soon after a failed initialization attempt. The message center displays the stability system disabled message when sensor initialization fails.

The steering angle sensor calibration. The Steering Angle Sensor is calibrated at the assembly plant. If the sensor is replaced, follow the calibration procedure.
ECE 13 Response

The electronic brake control module (EBCM) illuminates the ABS indicator when a malfunction which disables ABS is detected. Usually, the ABS indicator is turned OFF during the following ignition cycle unless the fault is detected during that ignition cycle. However, the setting of a wheel speed sensor related DTC causes the ABS indicator to remain illuminated during the following ignition cycle until the vehicle is operated at a speed greater than 13 km/h (8 mph). This allows the EBCM to verify that no malfunction exists, before turning OFF the ABS indicator. This reaction occurs even if the ABS indicator turns OFF when the scan tool is used to clear the DTCs. When repairing these vehicles, it is important to ensure that the ECE 13 response has occurred and that the ABS indicator does not illuminate after returning the vehicle to the customer. It is also important to verify that ECE 13 is not the cause of an ABS indicator which is illuminated when no DTCs are set, before attempting to diagnose other possible causes.
Driver Information Indicators and Messages

The following indicators are used to inform the driver of several different factors.
Brake Warning Indicator

The instrument panel cluster (IPC) illuminates the brake warning indicator when the following occurs.
• The body control module (BCM) detects that the park brake is engaged. The IPC receives a serial data message from the BCM requesting illumination. The brake warning indicator flashes at a rate of approximately twice per second when the park brake is engaged.
• The instrument panel cluster (IPC) detects a low brake fluid condition or a base brake pressure differential.
• The IPC performs the bulb check.
• The EBCM detects an ABS-disabling malfunction which also disables electronic brake distribution (EBD) and sends a serial data message to the IPC requesting illumination.
ABS Indicator

The IPC illuminates the ABS indicator when the following occurs.
• The EBCM detects an ABS-disabling malfunction and sends a serial data message to the IPC requesting illumination.
• The IPC performs the bulb check.
• The IPC detects a loss of serial data communication with the EBCM.
• A DTC is set during the previous ignition cycle which requires an ECE 13 response at the beginning of the current ignition cycle. The EBCM sends a serial data message to the IPC requesting illumination.
Traction Control Off Indicator

The IPC illuminates the traction off indicator when the following occurs.
• The EBCM disables engine torque reduction due to a malfunction and sends a serial data message to the IPC requesting illumination.
• The driver manually disables VSES and engine torque reduction by pressing the traction control switch. The BCM sends a serial data message to the IPC requesting illumination.
Stabilitrak Off Message

The message center displays the stabilitrak off message when one or more of the following conditions exists.
• The estimated temperature of any solenoid coil exceeds an acceptable limit. The BCM sends a serial data message to the IPC requesting this display.
• The BCM detects a failed brake switch. The BCM sends a serial data message to the IPC requesting this display. A DTC sets when this condition exists.
• VSES sensor initialization time is excessive. The EBCM sends a serial data message to the IPC requesting this display.
• Serial data communication between the EBCM and any of several other control modules is interrupted. The EBCM sends a serial data message to the IPC requesting this display or the IPC displays the message when communication with the EBCM is interrupted.
• The PCM is not able to perform engine torque reduction. The EBCM sends a serial data message to the IPC requesting this display. DTCs set when this condition exists.
• The EBCM detects an excessively low or excessively high ignition voltage. The EBCM sends a serial data message to the IPC requesting this display.
Service Stabilitrak Message

The message center displays the service stability system message when any one of many VSES-disabling DTCs is set. The EBCM sends a serial data message to the IPC requesting this display.
Service Traction Control Message

The message center displays the service traction control system message when any one of many traction control - disabling DTCs is set. The EBCM sends a serial data message to the IPC requesting this display.
© 2009 General Motors Corporation. All rights reserved.

Most likely Torque Management which you cannot turn off without a tune.

Vz28:
I did not notice if the ESC turned itself back on. Never thought to look. That is a possibility, I will be sure to check next time. Checking for hot rear brakes after a run is a good idea, I will try that also.

Wicked Mom:
Thanks for posting the Service Manual info. It doesn't directly say that stability control is still active when the traction button is pushed, but it doesn't say it isn't. I suspect it is active, although maybe at a lower level of control.

GAG8:
Thanks for the suggestion, but was definitely not torque management. I could feel the inside rear brakes applying when the car was getting loose.

Thanks for all the replies. Looking forward to the next autocross.

I've autocrossed with and without ESC, and although I'm not sure if any of the nanny controls are still there when the the ESC is off, it certainly frees up the car a lot, to put the control more in the driver's hands and make the car much faster.

On GXP with M6 the ESC didn't seem to get in the way even when it was left enabled. I think it actually helped me reduce the wheelspin in the turns, since the throttle pedal is very touchy. I've done just a couple of runs, first one with ESC on, the second one with ESC off.

My guess would be that off means off.

I try to run with it off when autocrossing. If the number of times I spun on my all season tires is any indication I would definitely say the computer is hands off when you turn it off. The way the all seasons chirp when they are laying on the sidewalls sure sound like something mechanical though.

I definitely notice a difference in the speed of my runs when I forget to turn it off. It almost feels like it is trying to slow me down to prevent wheel spin and loss of control.

I have not been out as much as I would like, and I have not found a place to practice yet, but I am learning that it is possible to "steer with the throttle" to some extent. It seems like this wouldn't be possible if the computer was trying to be motherly.

I've been helping with organizing an autocross yesterday, and I took a few runs with G8.. Pretty consistently I've been getting 0.2s better time with ESP on than off.It's hard to catch the moment when the rear starts sliding when powering out of the turn. Not that I was doing particularly well, looking at the data record, I've been screwing up different parts of the course. Then a friend of mine took a run with ESP off and did 0.7s faster than my best time :-)

The handling is pretty good. And the car seems to be surprisingly quick too, for such a big car.

On one of the runs without ESP I almost spun the car, so I'm pretty sure that when it's off, it's really off.

After some searching, I found out the following items of interest:

-Top Gear tested a Vauxhall VXR8 (which is similar to our GXPs, I would think), and did mention that when you select ESP OFF it is not completely off, but they hinted that there are ways around it...for some reason I can't find a direct link to the article, but it is out there

-I found another article reviewing a holden commodore (same car as g8) which mentioned that when ESP intervenes, the brake lights are on. So have someone watch the car while you are running with esp off. I do recall someone pointing out to me at the last autox that my brake lights were on while coming out of a turn, and I was NOT left-foot braking, so this could prove that esp still intervened.

V

I have been running my G8-GT in SCCA Auto Cross all year (2009). I turn the Stability Control off, but the antilock brakes are still active. The car will still step out when coming out of a corner and on the gas hard. If pushed too hard it will spin, but you really have to get on it hard to get that far out of shape. The GT needs suspension work to be competitive in F-stock. Over the winter I am going to replace the front sway bar with a larger one, go to ajustable Koni shocks, and buy a set of lighter wheels with Hoosiers. Right now the Mustangs are kicking my butt, but they have already made those improvements. Others at the track have told me to learn to run with the Stability Control OFF for better times. That's my two cents worth. lol

Mobeck

Some tidbits:

During that day I told about above, the same nationally competitive driver (no, not the one with best time) had an about 1s (out of ~40s) better run in my GXP than in a C5 Corvette. The Corvette was also on street tires, some Goodyear Eagle F1. Maybe those aren't that good.

Taking the best time of a nationally competitive BSP Miata, and PAXing it to FS, the best run in my car was ~2.5s off. That's on street tires. And the course was pretty tight, which should favor Miata. I'd be very interested to see, how it goes on the race tires. It just might be decently competitive.

On the data log I've seen transitional lateral Gs up to 1.0g and pretty typical 0.95g in the longer turns.

The problems for auticrossing the G8 are two-fold: the suspension is very soft, and the car is both long and wide and heavy. It's some 2" wider than a BMW 5-series, and it basically means that in a slalom it's like the cones are offset inwards by 2" for you. I think Mustang is even narrower. I don't think either of these problems can be solved within the stock class.

The bigger front sway bar will make the car understeer. I've tried that on Camaro, hated it, returned the stock sway bar back (only with the poly bushings). The single-adjustable Koni shocks are no panacea either. They're adjustable only in rebound, and you've got to run it pretty soft to get the decent handling and not wear out the front tires too bad. Took me some 4 years to figure that out. In the end the car balances nicely and I get close temperatures between fronts and rear tires but the suspension is still soft. Overall I'd say it was a waste of money and of a lot of time to learn how to set them up. I wonder if the double-adjustables would help, by stiffening the compression rate.

A couple of weeks ago a guy with a '07 Mustang and I have swapped the cars for one run. I was 0.7s quicker in his car than in my Camaro. Maybe it's just that my tires are shot by now. But also the Mustang leans a lot less, and maybe it's a little narrower.

I changed tires yesterday. The new ones are Bridgestone Pontenza RE-11s. I will run those next weekend and let you know if they made a difference.

Won't you get bumped outta F-stock once you start changing suspension components?

Scott,
F-Stock cars are allowed to change certain items. Among them are the front sway bar, shocks, tires, and wheels. Any aftermarket front sway bar is allowed, but you cannot touch the rear one. Any shock is allowed on all four corners, but it cannot have more than two adjustments available. If it has more than two you have to disable the rest of them by some means that is permament. Like if it has notches you would have to file off all but two of them so that they can't be used, you choose which two settings to keep. Wheels must be of the original size, width and diameter, with no more than 1/4" offset. R-compound tires of any width are allowed. You can't touch the motor at all, so no rechipping or flashing the box or anything like that. The air intake has to be stock too. I am not sure about the brakes. I want a set of Brimbos, but have to check the rules on that one. Hope that answers you question, or maybe brings up more of them. LOL
Dave Mobeck

Sab123- Thanks for the "tidbits". I went to "autocross school" earlier in the spring. My instructor hit on some of the items in your post. The Mustangs only weigh 200 pounds less than the G8. I know 200 is 200, but we have a horsepower advantage over the Mustang GT. The Shelby is another matter. hehe Another advantage for the G8 is the independent rear end and the near 50-50 weight distribution front/rear. I think the stiffer front suspension will work on the G8. The Camero is going to tend to push anyway due to the front/rear difference, maybe that's why it didn't work for you. Just a thought.

Could what he is feeling possibly be the rear diff doing its thing?

Scott,
F-Stock cars are allowed to change certain items. Among them are the front sway bar, shocks, tires, and wheels. Any aftermarket front sway bar is allowed, but you cannot touch the rear one. Any shock is allowed on all four corners, but it cannot have more than two adjustments available. If it has more than two you have to disable the rest of them by some means that is permament. Like if it has notches you would have to file off all but two of them so that they can't be used, you choose which two settings to keep. Wheels must be of the original size, width and diameter, with no more than 1/4" offset. R-compound tires of any width are allowed. You can't touch the motor at all, so no rechipping or flashing the box or anything like that. The air intake has to be stock too. I am not sure about the brakes. I want a set of Brimbos, but have to check the rules on that one. Hope that answers you question, or maybe brings up more of them. LOL
Dave Mobeck

Ah, that explains it. I ran my 93 RX7 a couple of times in SS. I remember after I removed the stock airbox for a CAI, they told me it wasn't legal for the class. Seems funny to me that a CAI will knock you out, but different shocks and swaybar won't.

Sab123- Thanks for the "tidbits". I went to "autocross school" earlier in the spring. My instructor hit on some of the items in your post. The Mustangs only weigh 200 pounds less than the G8. I know 200 is 200, but we have a horsepower advantage over the Mustang GT. The Shelby is another matter. hehe Another advantage for the G8 is the independent rear end and the near 50-50 weight distribution front/rear. I think the stiffer front suspension will work on the G8. The Camero is going to tend to push anyway due to the front/rear difference, maybe that's why it didn't work for you. Just a thought.

Actually, 4th gen Camaro Z28 has something like 54/46 weight distribution. And the handling can be balanced with the suspension stiffness. I once had an FWD Mazda-323 that I've set up for mild oversteer by taking off the front sway bar (and it had some strange springs from the previous owner). It was a lot quicker after that.

A bigger front sway bar without matching rear one is a compromise: it reduces the roll, so the short turns are easier, but it adds understeer in the long turns. The understeer in an RWD car has a good side too: it helps you put down more power exiting the turn. The driving style needs to match: you give up on the turn entry and through the turn to get a better acceleration out of it, and you use a late-apex line.

Is the current Mustang really so heavy? 4th gen Camaro without driver weighs about 3450 lbs, G8 4050 lbs., with full tank of gas. '88 Mustang weighs about 3000 lbs (mine is minus interior plus roll cage).

I do recall someone pointing out to me at the last autox that my brake lights were on while coming out of a turn, and I was NOT left-foot braking, so this could prove that esp still intervened.

That could just be you needing the brake switch recall performed.

I've been autoxing twice in the last several weeks. ESP OFF provides a much better time than ON, as well as leaving you open to spin because of driver error.

That could just be you needing the brake switch recall performed.

I've been autoxing twice in the last several weeks. ESP OFF provides a much better time than ON, as well as leaving you open to spin because of driver error.

Sorry, I should have been more clear...my brake lights were observed TURNING on after being off while exiting a corner under aggressive throttle application, which could be determined by the aggressive exhaust note when i got on it - maybe I can get some video next time. Does the brake switch recall apply in this case? I don't think I have it as an outstanding recall on my gxp.

After my last autox runs, I was over 4 seconds faster with esp off on a ~55 second course, so I agree leaving it off can be much faster. The reason I believe it is still intervening is that even while purposely overdriving such that I should have been in a very extreme oversteer case, I was unable to get the car to spin or approach a spin (but it did oversteer slightly and in a sort of slow motion). I think a sudden very high yaw rate (even for a split second, which sometimes can help with rotation/corner exit) causes it to kick in even if it is in "esp off" mode.

In addition to the Top Gear Vauxhall vxr8 online review where they mention the esp not really being off, there is an article by Autospeed where they test an adjustable stability control plug-in module (search for Autospeed adjustable stability control - very cool idea!). They mention that on the holden ve (g8) the brake lights are on whenever the esp is intervening.

I'd like to just ask the right Pontiac/Holden rep. and get to the bottom of this :)

V

Maybe you are right. I don't know. I do know I can do deliberately wild maneuvers in snow and rain with the ESP off, but those are at relatively low speeds and g-loads compared to autocrossing. Maybe it's picky about forcing itself? But I can't say I felt like something was kicking in to keep me straight when I autox'd. Another 09.5 update, perhaps?

Who has had a track biased alignment done? What do you think before and after on autox or track. I havent been on the track yet but will soon with a pedders track II setup. Any advise on camber settings?

I went to an autocross in the rain. This time the car was much easier to drive with ESP off. Weird, considering how I liked it better in the dry with ESP on. Either I'm getting used to the car, or the car is getting used to me, or the ESP is overly active on the more slippery pavement, or the suspension works better with lower G loads.

I can vouch that even if the ESP OFF is lit, it's not completely off. I witnessed this on a drag strip, but same difference. I let my dad make a pass in the car, and videotaped it. He didn't do enough of a burnout, so he spun a good bit in first. Plus, he got out of the groove, and the car got squirelly on the 1-2, and 2-3 shifts. I distinctly saw the brake lights some on in a fluttering fashion during each of these "traction issues." I thought he got scared and touched the brakes, but he assured me he didn't. Plus they fluttered on and off faster than a human foot could do. This convinces me that unless you tune this out somehow, off really isn't off.