FSportIS

iTrader: (13)

What is the difference between:
1. ISx50 traction control on
2. ISF in PWR mode
3. ISx50 traction control off

andper10

I agree, there were too many times where I could have been rear ended because of the stock traction control, which is why I did the ISF steering ECU swap. Haven't had anything like that happen since. Just be careful with how much throttle you use with traction control off in certain situations, especially while turning and/or in the rain.

redspencer

iTrader: (1)

1. ISx50 drives at 6/10th-7/10th at the limits before VDIM interferes (very intrusive)
2. ISx50 drives at 8/10th-9/10th at the limits before VDIM interferes. Steering feel and feedback is also significantly improved.
3. ISx50 drives at 10/10th without any assists (except for ABS).

andper10

Going from memory based on past research & experience with my 07 IS350 before and after the 11+ ISF steering ECU swap:

1. If you are accelerating and one or both wheels spin (even just for a moment), it drops the RPMs significantly (to about 1k) for about 3 seconds even if your foot is planted to the floor. This can be caused by something boring like a slight bump in the road or a small puddle. It also creates a terrible situation when you are pulling out into traffic and accelerate a bit too much before you finish the turn...a rear and collision waiting to happen. This is for 06-07. Slight incremental improvements were reported for 08-09 and again for 10-12.

2. If you are accelerating and 1 rear wheel spins, it brakes that wheel only and doesn't reduce RPMs. If both rear wheels spin, it reduces RPMs to the 2k range momentarily (probably less than a second). It probably brakes and/or reduces RPMs if you understeer badly but I don't find that happening outside of panic swerving/braking so it is hard to tell for sure. This is for 11+ ISF. Previous ISF years were still better than any year of ISx50 but more intrusive than 11+ ISF. 14+ ISF is a different part number but there are limited ISx50 swap reports for it and it doesn't appear to feel much different than 11-13 ISF.

3. Allows one or both rear wheels to spin with no throttle adjustment or braking. If you don't slow down enough before a turn or give it too much gas during a turn, you need to be able to recognize it quickly and lift and/or brake quickly enough to keep the car from sliding out of your lane (or off the road completely), or spinning out. If there is someone else turning next to you when this happens, there is a good chance you could hit them. If you drive through a puddle, some gravel, some dirt, over a bump, etc. with 1 or both wheels while accelerating (even in a straight line), the back end may slide out in the direction of the spinning tire and you will want to quickly lift, counter steer, and/or brake depending on the situation. Accelerating in the rain can also produce unpredictable results that you may need to lift for, even at moderate amounts of throttle.

FSportIS

iTrader: (13)

I really like your quantitative way of defining it. Technically wise, what is going on in 2.? How does the system determine when to kick in? Could you provide further more technical answer? How does it help the steering, throttle respond etc?

I am contemplating on getting that ECU

redspencer

iTrader: (1)

Andper10 did a fantastic job providing a more detailed answer between the three modes.

To add to his comments, here's a great video from Lexus demonstrating the technical breakdown of VDIM Normal mode and VDIM Sports mode:

EDIT: Seems like you have to go on the actual YouTube website to watch the video demonstration. Simply click on the title on top of the video to do so.

FSportIS

iTrader: (13)

Wow, thank you andper10 and redspencer so much for such great information! You guys rock. I think this information is very helpful to the community. The mods should index this somehow.

andper10

Glad I could give back some! These forms have been very helpful for me.
UPDATE: Tried activating this inspection mode setting on my car and unfortunately it is not permanent. Looks like the best way to disable it is to hold down the TRAC button for 5 seconds while stopped (or do the "pedal dance" while in park on the 06 models). Both methods are reset every time the car is turned off unfortunately. I think I remember reading about someone who wired a switch or relay to disable/enable TRAC/VSC on demand while in motion, but there weren't many details in the post.

Jeff Lange

iTrader: (1)

I believe, but am not sure, that a product exists out there, that after the car is started, will simulate pressing the button for you, which would effectively disable the TRAC/VSC every time, that said, you'd still need to wait the 3 seconds for it to happen.

Jeff

andper10

Interesting...I wonder if the button could be replaced with a rocker switch that could be left in the on position. I can't think of a reason that holding the button down indefinitely would cause any problems, and a quick off/on/off cycle would allow TRC/VSC to be reenabled while driving if desired.

Jeff Lange

iTrader: (1)

The issue is that it would need to be in the off position before starting the car. Having it in the on position when you start the car would not disable TRAC/VSC.

Jeff

FSportIS

iTrader: (13)

Man, what is so hard holding the button for 5 seconds lol. Don't be too lazy guys

And then you gonna say the car need to be in 0 MPH before you can turn it off, the reality is that you gonna stop in the red light or in traffic at least once getting to your destination anyways so just press the damn button for 5 seconds and call it a day

andper10

I just think it is an interesting challenge. Now if I could trick the computer into thinking the car was not moving and have the ability to turn it on/off while in motion I think that would actually be useful.

Bummer, didn't realize this. I tried it out and you are right (of course haha).

I pulled the panel and looked at the wires going to the traction control button out of curiosity. There are 4 wires: white with black stripe, green, red, and white. I am guessing the white pair is for the backlight and the red/green pair is for the actual switch (or maybe vice-versa). I might try to make a "simulator" using a timer if I get some free time. If I could find somewhere to buy just the male and female connectors I could even make it plug and play and sell it to CL members in the Classifieds.