mmarshall

What probably happened was that you got the brakes too hot. VSC systems, of course, usually work by applying the brakes on one or more wheels to keep the car in line while turning and prevent oversteer or understeer. Get the rotors and pads too hot and sensors will lock out the VSC for awhile (usually with a warning light) to help control brake temperature until things get back to normal. That is probably also why the car was limited to 25 MPH for awhile. It may have also affected the ABS as well.......depending on the system design.

Overheated brakes can be dangerous, not only because of fade, ineffectiveness, glaze on the pads, and rotor warp, but, if severe, can boil some of the brake fluid as well.

rominl

iTrader: (4)

there is a temperature sensor for brakes as part of the vsc?

mmarshall

There is with many VSC systems, though of course there are some variations. In general, it temporary locks out or restricts the VSC when continued use of the VSC or traction control would take brake temperature to unacceptable levels (some traction control systems also work by both braking action and cutting back on engine power).

Of course, the system has a warning light when this happens........which is a disclaimer, so that if the driver burns up the brakes or powerslides himself into a spinout or serious trouble it is on him, not the company......and, in some cases, a programmed limp-home speed limit so that he can't do that, period.

IS350jet

Mike, Great wright up on the ISF. We had a great time at the track. It was a pleasure meeting you along with Kofi, Lexizm, Mr. Johnson, Adrian, and Josh. I agree completely with your assessment of the ISF. It is truly an amazing car. In a way, I'm glad Lexus will be limiting its production numbers to keep exclusivity alive, unlike the up coming M3.
I felt the most amazing part of the car was the massive amounts of grip from the PS2's. Also, the transmission was nothing short of incredible. In auto mode you could hear the shifts but barely feel them. In sport mode you will not find a faster shifting transmission in a production car.
Power and torque were there but somehow the sound of the secondary intake plays games with your mind making you think that a huge power band just opened up but in reality it didn't (well maybe just a little but nothing like it sounds.) I got pretty lucky with the ISF because it was just me and the instructor, no other passengers.
I had the IS350 for the warm up car but I was the last one to drive it so I had to go pretty hard to keep up with the lead car. Again, by the time I got to drive the IS350 it was just me and one other person. The IS350, BTW, is an amazing car in its own right.
All in all, a great day at the track. Go Lexus!!

Mike.

newr

I don't think this assessment is correct. We have seen professional drivers tested the ISF in various publications. I am pretty sure they pushed the car much harder than these guys did and none had this problem of the brake getting too hot that VSC went in limp mode. This happened on the 2nd lap so I don't think the brakes were that hot. Other high performance sport cars also have their own VSC systems and I have never heard of a car goes in limp mode because the brake gets too hot at the track.

I think this problem was just a fluke on this particular ISF. However, if you are right about Lexus VSC system being designed like this, then it's a real let down for people who do take their cars to the track.