Traction control issues at the track?
12-02-13, 06:24 AM
#1
Traction control issues at the track?
On saturday I did a charity drive event at MSR Houston. I have an 06 so its the pedal dance model but I did not do the dance. I did 2 sessions in the morning with no issues and there was a few hour gap for the afternoon session. In the afternoon session, I lost the ability to steer like my steering input was being cancelled and the car just kept going straight. I got black flagged for going off the track and I didnt feel comfortable going back on the track. Checked my tire pressures and they were fine, couldnt find anything wrong mechanically. Is this the traction control doing this? I felt like I had a huge reduction in grip. We did some pace warm up laps in the morning, but in the afternoon we just went at it with no warmup laps. Im guessing this was a large factor in losing grip as I was driving the same pace as the morning sessions but had no problem there. My instructor has an ISF and he said the same thing happened to him one time when he forgot to turn off the TC
12-02-13, 06:31 AM
#2
I have never heard of traction control turning steering off...typically it engages the brakes and kills power to the engine if left on and driving aggressively. You are saying that you were turning the steering wheel and the car just went straight? Like you had no steering at all, or it had massive understeer and the wheels were turned and the vehicle slid straight?
12-02-13, 07:38 AM
#6
If it was just understeer, then it could be that the weight was not transferred enough when braking to put pressure on the fronts or getting a little too happy with the gas early.
Did all the warning lights come on when this happened? Did you hear a beeping noise?
Did all the warning lights come on when this happened? Did you hear a beeping noise?
12-02-13, 07:41 AM
#7
yea I got a couple warning beeps during the morning sessions but didnt lose steering ability. My instructor was puzzled because I was driving it the same as the morning sessions. Only thing we could think of is the tires werent warmed up like they were on the morning session. I went off the track twice in the same turn, which is after a chicane.
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12-02-13, 10:41 AM
#9
Too many variables to really know what caused this, but if you didn't see warning lights or hear beeping when this happened, then it is pretty safe to say that this was not a result of traction control being on or engaging.
FYI...every time I have had my IS on a track, traction control is always turned off
FYI...every time I have had my IS on a track, traction control is always turned off
12-02-13, 10:44 AM
#10
yea next time I go out I will turn off the TC with a pedal dance. Yay for 06
I had crappier tires while on TWS back in 07 but it was hot. Im starting to lean into tire temperatures affecting my grip. I cant remember exactly if i heard the TC go off before going off track. I just know I remember hearing it several times that day.
I had crappier tires while on TWS back in 07 but it was hot. Im starting to lean into tire temperatures affecting my grip. I cant remember exactly if i heard the TC go off before going off track. I just know I remember hearing it several times that day.
12-02-13, 10:50 AM
#11
Well, I guess if you heard it beeping at you at least that means you were pushing the car 
Try it without traction control, it is so much better. You have total control, and there is less hesitation when you gas it at the apex...plus the car is slightly faster too
Nice to hear another IS taking it to the track...
Try it without traction control, it is so much better. You have total control, and there is less hesitation when you gas it at the apex...plus the car is slightly faster too
Nice to hear another IS taking it to the track...
12-02-13, 11:35 AM
#12
yea I was holding my own out there against all kinds of other cars. I wouldve done a lot better if i drove in manual and had TC off. I didnt know the track so decided to drive it in auto which was always a gear lower than what it shouldve been. I will get my revenge sometime on that track in the future.
12-02-13, 11:51 AM
#13
I'm fairly certain that it's the VDIM system (possibly the EPS-assist portion) that's fighting to keep your vehicle from "losing control" by resisting your steering input and minimizing any hard turn steering inputs. With VDIM fully activated, the car only allows a certain cornering threshold to be met before it begins to apply the brakes, cut fuel, and resist further steering input, all in an attempt to maintain its stability. This link provides a good visual of how VDIM attempts to keep the ball within the bowl and to not allow it to achieve its 10/10 limits: http://www.lexus.com.bh/technology_e....asp?model=All. With the IS-F, VDIM Sport mode allows the handling threshold to be reached at near 10/10 before kicking in.
During the initial reviews of the 2006 IS350, many journalists complained at how intrusive VDIM was and during one slalom test from Autowek, the IS350 w/ VDIM was producing slower speeds than what a minivan could produce.
From my own personal experience, I also have experienced the steering input being held back during a hard corner where my tires were not turning to the same degree with what the steering wheel was doing. I've done several tests back-to-back with VSC on and VSC off and noted that with VSC off, I have full freedom to maintain my intended driving line (provided my tires have enough grip). With VDIM on, there's definitely more understeer exhibited, regardless of what angle my steering wheel may be. A thread was made a while back that showed when you turned VSC off, it also disables the EPS-assist function: https://www.clublexus.com/forums/is-...t-exactly.html
During the initial reviews of the 2006 IS350, many journalists complained at how intrusive VDIM was and during one slalom test from Autowek, the IS350 w/ VDIM was producing slower speeds than what a minivan could produce.
From Autoweek:
"The IS 350 had hinted it might be a contender. It feels well-balanced and tossable, controllable at the limit and great fun... as long as you keep it under 30 mph. Now how the heck are you supposed to do that? We have never gone through the slalom at anywhere near 30 mph. Even in the most bloated minivan or the most flatulent SUV, we are well over that speed. A car like this should achieve at least 45 mph in our tight, 490-foot slalom.
You cannot do the slalom at 30 and call yourself an enthusiast driver, or even alive and aware of your surroundings. And VDIM is not just a suggestion. It shuts down the whole operation by braking various corner wheels and cutting power to the engine until you are crawling around through the cones like a flopping drunk on the sidewalk.
"The IS 350 had hinted it might be a contender. It feels well-balanced and tossable, controllable at the limit and great fun... as long as you keep it under 30 mph. Now how the heck are you supposed to do that? We have never gone through the slalom at anywhere near 30 mph. Even in the most bloated minivan or the most flatulent SUV, we are well over that speed. A car like this should achieve at least 45 mph in our tight, 490-foot slalom.
You cannot do the slalom at 30 and call yourself an enthusiast driver, or even alive and aware of your surroundings. And VDIM is not just a suggestion. It shuts down the whole operation by braking various corner wheels and cutting power to the engine until you are crawling around through the cones like a flopping drunk on the sidewalk.
Last edited by redspencer; 12-02-13 at 12:08 PM.
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